1. NO IMPELLER, NO RAW WATER PUMP - MARINE GENERATOR

[@diegokleiman1592]

Wow, TYSM for this video. You always seem to come to the rescue when I'm trying to figure out boat issues. Right now it was THIS one so once again, TY for all the information you shared here.

[@Every_Day_Adventure]

don't worry, your artistic skills are well suited for your technical episodes, be happy. I enjoy ALL of your video's and happy to have you back.

[@CatamaranImpi]

lol - thank you very much! I know how to 'Be Happy' - I feel we are very fortunate to feel happy most of the time :)

[@rogerbarker165]

Good one Brent. From a fellow farmer and yachty it was good to watch someone else messing around with pumps for a change. They are a never-ending source of 'amusement'.......!!! Great instructional vid' mate, it should help a lot of people. Well done. Rog

[@CatamaranImpi]

Nice comment Roger - just had to replace the borehole pump back in SA on the farm - fun and games. At least my brother is handling these things nowadays :D We hope a lot of people get some value from the sharing ... that's what it's all about. I think the manufacturers should be refining their builds to make life less of a hassle on the oceans Cheers my friend Brent

[@gavingrantham136]

This has been some of the most useful info that I have come across from any of the Youtubing channels that I have been watching - much-appreciated Thanks and happy sailing & fare winds - Baie Dankie.

[@CatamaranImpi]

Aye Gavin - so pleased we could share that with you then !!! Fair winds maat!

[@niccat7051]

Excellent tech video!! Well drawn and filmed!! And a very good permanent fix to a problem that is the pain of all boat engines and generators! Thanks for sharing!

[@CatamaranImpi]

Cheers NICCAT - the drawing does not come naturally to me so I'm pleased it came out ok. The fix has been great - we did the mod somewhere around 4 1/2 years ago and not had an issue with he pump once ... touch wood :)

[@7kmkeane]

Nice job Brent! very well done and explained. I can tell you are proud of the work you did, and justifiably so! It was the perfect balance of starting with the basic principles and then getting down to brass tacks. Keep up the good work, us new boat owners really appreciate it!

[@CatamaranImpi]

Thank you very much for the comment. I know some of the technical folks want a more 'to the point vid', however I really want to aim these vids to the 'new to sailing folks' so they get a better understanding of everything around the specific modification. This way they may be better equipped to help themselves out at sea with a trader knowledge of the basics. So - very much appreciate your comment ... Cheers for now Brent

[@pnwesty7174]

Wonderful. I understand the basics, but a pleasure to watch anyway. All the bleeder valves are super smart. Thanks, guys!

[@CatamaranImpi]

Hey Shawn - thanks my bro ! Trying to share more for the 'newbies' to owning boats and also get the mod across to the more tech folks too. I think the more technical guys will just fast forward sections. The bleeder valves have made our lives a lot easier for sure :) Cheers my friend - always nice hearing from you

[@peterlibretto4517]

wow, such a fantastic idea, I have a 6.5kVA Onan generator and have just bought 2 x impellors ready for when mine fails, although it seems a bit of work, it is definately a way of eliminating this weak part, thanks very much for explaining this in such detail

[@CatamaranImpi]

Any time Peter - we’ve had ours working this way for years now and full time sailors. We’ve never lost an impeller again! Just a heads up to make sure of the AC Amps needed for your boat as the pump will draw AC Amps to operate. Happy sailing Brent

[@peterlibretto4517]

@@CatamaranImpi Thanks Brent, just one question, I have checked out the March pumps data sheet and it says it must be located below the water line and have a flooded suction, I guess this is why you have the bleed valves at the pump and air bleed? I also guess that you only need to bleed this through once and not every time you run the generator as it has a non return valve at hull? thanks again Brent much appreciate all the time and effort you put into sharing this.

[@CatamaranImpi]

@@peterlibretto4517 The bleed valves at the pump are for the very rare occasions the pump gets air locked. Sometimes when cleaning out the screen filters air gets into the system and to get the pump running again with ease we bleed it this way ... just makes life easy for one as some folks loosen off clamps etc. etc. - much easier just to toggle a bleed valve. Yes, if your system is nicely clamped and tightened you will not have to repeat bleeding - it takes care of itself. Always a pleasure to share and hope it makes cruising life a bit easier for you. Cheers for now ... Brent

[@RobertForrester_FPV]

Great video. I am always excited to see how everything works and better ways to make it happen. Keep up the great work.

[@CatamaranImpi]

Thanks Robert - amazing how much there is to a boat and the systems onboard. Many sailors who start cruising tell us they had no idea such a small piece of fibreglass in the ocean can be so complex :D

[@CaptainBobSVChimera]

Excellent video. I hope I can remember all of that for five years!! Our new Lagoon 450F is going into charter for it's first five years. This will be one of my first upgrades!!

[@CatamaranImpi]

Well done Bob - you must be very excited :) I think the later Lagoons have installed some 'boost feed pumps' to keep pressure at the impeller, but this change will still be way better in that you never need to replace an impeller again. Look forward to seeing you sail off on that 450 ... cheers for now ... Brent

[@laurentfroggy6631]

Excellent video Brent but I will have to watch it again and again. 🙈 thanks for your reply and yes it would had been nice to meet up. C'est la vie. Best from HKG 🇭🇰

[@CatamaranImpi]

Cheers Laurent - maybe in HKG :)

[@laurentfroggy6631]

Let's hope so :)

[@orangewhip6261]

Hey Brent, I like the new intro walk through of Impi, she really is a pretty boat. That is a very clever way to cool the gen set and get rid of the mechanical impeller, and very tidy bleeding system. You also have a nice emergency bilge pump for that hull, if you need it. Great video as usual. Scott

[@CatamaranImpi]

Hey OW - Scott :) Nice to hear from you again. Yes, we really enjoy our little ship - she is a 'lot of boat' for the size, and at 45 ft this is a great size for a couple cruising the world. Actually, on the bleed system I added more of those fancy taps to the end of the tubes you saw - I figured it would be good to have taps on the end so when the tubes are rolled away no salt water can drip into the cabinet. And yes - very good point you have around emergency pumps - we have many in the boat including the eckwash pump, shower pump, toilet pump and more :) Cheers for now Brent

[@lightning9279]

Brent thanks for going through the effort of making a great education vid. Job well done.

[@CatamaranImpi]

Cheers Light Ning - always a pleasure and thanks for commenting :)

[@bobfox321]

Incredible amounts of problems and negative cash flows are caused by the rubber impeller. This important video MUST be seen by all sailors and Captains that have suffered failures on the open seas. The only people who will NOT like your ingenious redesign will be the those that have made millions of dollars from all the services provided as a result from FAILED IMPELLERS. Thank you Brent. A true service to all mariners! God Bless.

[@CatamaranImpi]

Hey Bob - you are an awesome guy man :) Yes, I must admit that I was wondering if the suppliers were loving the gloomy faces as we sailors haul out the extra bucks for rubber impellers and specialised hoses :) Actually, Lagoon, in this instance, should have asked Onan to switch the gear to the closer panel. This would have illuminated the need for that awkward pipe which is a very expensive item to replace. Cheers my friend - all the best Brent

[@SailingSisu]

Awesome, will for sure do it, what do you think, should we do it from the start? Before it breaks?

[@pearadisevlogs7467]

Good job prof! Your instructional vids have been really helpful, informative and absolutely entertaining! Smart mods too, I particularly liked the bleeder valves. So smart! Intelligent design, or in this case, redesign is a beautiful thing. Thanks again for taking the time to share. Huge kudos to you! :)

[@CatamaranImpi]

LOL - Prof !!! All good and always nice to share stuff we learn along the way. Yes, we feel this works well for us - I can see some suppliers not quite liking the idea though ;) Anyway - works a treat on Impi and has made life MUCH easier - I really did not like changing that poorly designed rubber impeller - let alone the work load - overtime it meant trying to keep salt water out of the cocoon. Cheers my friend ... Brent

[@tomasmontero7219]

the real way to do it. in this video you makes disapeared the nightmares of generator impeller. superb and thks

[@CatamaranImpi]

So happy we could share this with you Thierry. We have been on this system for years now and never had another issue with the raw water system ... and we sail full time on the boat :)

[@stevel7465]

Hi Brent. Another great video. Your tech videos are really well done and give a good mix for all. I'm really happy to see you posting again. Did you announce what you decided to do about a new boat? Let me know what you are going to do about your 440. I've been leaning towards a 450 but it's obvious how much care you take on Impi. Cheers from Canada Steve

[@CatamaranImpi]

Hi Steve - thanks for the awesome comment. It's lovely to be able to share on the things we learn. We decided to hang onto Impi for now - the 50 is beautiful but for the amount of upgrades we have done to Impi and the amount of upgrades the 50 needs to be anywhere close to where Impi is at for extended world cruising, we feel we would be loosing on the sale (people would not realise the advantages / build ins with Impi) and spending too much on the 'buy' (money and time) to be in a similar position with a later model boat. We are still watching 'this space' and are waiting for the Leopard 50 to be released so we have some comparisons. What is evident to us, is that the manufacturers have not yet come up with a dedicated 'living at sea' range of catamarans' for extended sailing. Even Outremer for example, have come a long way in this regard, but the boat is not designed to carry the weight for sailors who want to equip their boats with all the home comforts. Yes, taking care of Impi has come at a cost but certainly, the boat feels fresh and new and we have her at a stage where we spend little to no time on repairs ... Only maintenance ... and that is really nice when sailing :) Many of your fellow Cnadians here in NC at the moment - have had a few visiting the boat ...awesome folks Cheers for now Brent

[@abdullaalsulaiti1450]

Very good video easy explanation for difficult things

[@CatamaranImpi]

Pleased you could follow my explanations - always a worry when sharing technical stuff :) Thanks for commenting Cheers for now Brent

[@sickjohnson]

Very well done Bent! Now I have to look up that pump with no shaft and a magnetic impeller.

[@CatamaranImpi]

Thanks again - March Pumps :) Kent at Just Catamarans could match it for you if you purchased a pump through them I am sure. I do actually show in the vid, the pump we installed for our model Onan

[@sickjohnson]

Just wanted to see how the magnets work to move the impeller is all Brent, never seen one of these pumps before is all. Very cool, thanks! ;)

[@graeme-sailingskeptic]

Nice job mate - great video and some excellent solutions!

[@CatamaranImpi]

Thanks Graeme - always a pleasure for us :)

[@hezi973]

I was going through your videos hoping to see how you rigged your sails so you can reef at at other point of sail except head to wind. This is an interesting topic for an aspiring sailors :) If you have a video I missed, I would love to get link. If there isn't, I hope to see one in the future. Thank you for the free advices and safe sailing!

[@CatamaranImpi]

Hi 👋 there Yeah sorry I haven’t put up a video with us doing that - there may be some footage where we are doing it without really explaining it but basically we do it with a square top main sail and previously with a regular main sail prior to purchasing the square top. It’s easier with a regular sail but very doable with the square top too. The trick is to ease off the halyard foot by foot whilst cranking in on the reef lines but making sure to use the motion of the waves rocking the boat to square up the luff and leach tension of the sail as you proceeded . It takes a bit of practice but once you’ve developed a technique that works on your rigging you’ll get it . So: main halyard eased off little at a time and bringing up the tension through the reef lines because you don’t want to drag the sail down the shrouds or bend the battens backwards although slightly so is ok 👌 I’ll see if we can do a video on this when I get back into the water (hauled at the moment doing rigging ) - a lot of folks do query it so it would be worth doing. I think way back I put up something on Facebook about it with some footage but in light winds - I need to do it with some power in the wind Cheers 🍻

[@mikeferguson2828]

Nice video. Don’t you just love working on your boat hey. Music to my ears so nice to accomplish something. I feel in touch with mine working on her. 😉

[@CatamaranImpi]

Absolutely Captain Mike - I love to plan for a task like this - prefer preventative maintenance over emergency repair stuff :) I did not like changing out those rubber impellers - on my boat I was down to like 70 hrs for a change Cheers for now Brent

[@mikeferguson2828]

Catamaran Impi sounds like my fan belts on my yanmar alternators 😊. I need to change to serpentine belts and pulleys or at least double pulleys.

[@CatamaranImpi]

Serpentine is great but fairly expensive. Actually, on the Yanmar engines I have heavy alternators - they pull 175A Prestolite alternators as well as the original 80A Hitachi. I installed a double pulley to the front pulley, so 3 grooves - run the big alternators on double pulley and it really works a charm. One can always use a little belt dressing to help it along until the mod :)

[@toru7a]

Nice job there Brent (interesting). Can never have too many taps...within reason lol. You should see our house system, a combination of gravity and pressure systems with taps for various configurations.

[@CatamaranImpi]

Hey thanks Don - it sounds to me you have an interesting set up in your home :D Ana smiles at me with these taps. I keep buying the damn things and always looking for a spot to fit them :D

[@rdprdputube]

Do you need to bleed the pump everytime you want to run the generator? I guessing you would, since you have the anti-syphon installed. You mentioned you want water to drain away when the generator is not in use.

[@CatamaranImpi]

freshroasted coffee - hi and no! One only bleeds the system when water drains back to the ocean after cleaning the filter screens or if your non return foot valve at the ocean pickup gets stuck etc. in these scenarios having the ability to bleed it quickly and keep salt water out of the generator compartment makes the set up a huge benefit for one. As for draining away water - when storing the boat for a long period of time it’s beneficial to get fresh water through the system. I hope this helps

[@markharrison674]

Thanks for that question now it all makes sense

[@rdprdputube]

@@CatamaranImpi seems like the anti-syphon loop is not needed. Also makes me ask, how would you get water on the pistons, unless you have a cracked head or broken head gasket?

[@tomasmontero7219]

I have already commented how great is your video confirming all the nightmares i had with impeler on generators on my previous boats i owned. As generator are not at sea level the failure of impeller is automatic and invetiable with all the troubles to look after teeth etc.. But i have a question.. i have an new boat in production and the shipyard confirms there will be no issue because on this particular boat the generator is at sea level.All their boat have no issue with impeller on generator So Should i trust them or go your way with a feeding pump and no impeller??? cheers and thks

[@CatamaranImpi]

Hi Thierry - thanks for the comment :). I am getting ready for bed so will quickly answer here. Yes, the generator being at sea level will mean the impeller primes easier and as a result it will last longer. I would say that with the generator being at sea level the impellers will give you good service much like the impellers on the raw water side of the main engine. The shipyard will also install a siphon break system to make sure sea water does not keep flowing after the generator has shut down. I would probably go with the raw water pump as set up by the factory if my generator was at water level, and I would also service it regularly enough to make sure the impeller fins do not break and go into the cooler. Cheers my friend and look forward to seeing your boat on the water :) My best Brent

[@tomasmontero7219]

Thank you so much

[@Swizzenator]

Brilliant video Brent. Can you explain where you connected the March pump to? On the genny itself or somewhere in the electrical panel? Thank you for this. Would love to see you do a video and recap on your first years of cruising and the pros and cons. And also your plans for the next xx years of cruising and possible track. Also how many hours on the genny and have you done a rebuild if you have used her a ton of hours. I've got 500 hours on my new to me Lagoon 450 and hope to have many happy hours of use with proper maintenance. Cheers to you both.

[@CatamaranImpi]

Hi Mike, The March Pump is connected to the output of the AC side on the generator. I.E. some generators have a an external AC plug you can plug something into. It delivers AC current only when the generator turns. You can simply wire put a plug on the end of the March Pump cable and plug that in. If your Genny does not have an AC outlet I would advise to get an electrical guy to wire one in for you. In the video you will observe a plug adapter rack on-top of the generator. That is wired to the output of the generator and allows for multiple ac appliances to be wired into it. One of them is the March Pump. Mike - we have started a video on our ravels so far since leaving SA on Impi, we need to put out part 3. We are not sure where the winds to the future will carry us - we are a couple who literally go where and when we feel ready to do so :) If well maintained your genny will give you at least 10000hrs but needs to be well maintained. During that time you will need to clean the coolers and some other ancillary repairs. A generator does not like to 'idle along' - it needs load, so when running it use appliances to keep load on it - or in our case we have heavy charging devices, dive compressors to fill tanks and so on. I would also recommend cleaning and checking the mixing elbow from time to time. Enjoy the 450 Mike - awesome to be out there hanging off the islands :) Cheers fro now Brent

[@michaelbrown8545]

Seems unreal that no one has come up with a better material for the raw water pump impellers in this day and age, I think the manufacturers believe if you change them every 12 months you wont have any failures and they are fairly simple to replace. Must be a few 1st time boaties that have learnt the hard way though especialy those that store there boats on the dry for long periods. Nice job on the altetnate fix and instruction. Cheers mate.🍻

[@CatamaranImpi]

Thank you Michael - the alternate fix has been fantastic for us over the past 4,5 years now - never had an issue again with the Raw Water pump side of things. Cheers mate - have a coldie on me :)

[@rdprdputube]

Do you think this type of system can be used for main engines in a cruiser, given correct flow rates?

[@seatravel8536]

Excellent video and solution to a common trouble point! Have you considered doing same for engines? Only see the 220v as a no go for engines

[@CatamaranImpi]

Great stuff Sea Travel :) I see you are thinking ahead already - yes - the voltage would have to be 12v - the pump rated for the same flow and the pump to turn on with the engine and off with the engine automatically. Otherwise could cause flooding on the engine

[@SkypowerwithKarl]

Very good fix! The reason that the impeller life on your application was so short is the hight the generator is above the water level. That’s a long hose run and it’s dry for a time each time it starts. For others that want to replicate these results, remember these centrifugal pumps must be installed below the water line static and under cruise conditions. They don’t like trapped air pockets(did you see his little vent valve)? They have zero ability to prime. I highly suggest that you have a screened inlet(though hull), the kind that has perforated holes and shaped like a wedged door stop. The only criticism is the placement of the flow valve before the strainer is questionable if even necessary as is the siphon break.

[@CatamaranImpi]

Hi Karl - thanks for the great comment and for sharing. I agree the raw water impeller can't handle the height above water although Onan (Cummins) says it's within spec and should cope ... Cummins themselves contacted me to discuss the modification and I was told they are doing this for their commercial customers, and I think they realize the raw water pump is not living up to the spec. Lagoon placed the 'flow valve' / 'check valve' close to the stopcock as a means to prevent backflow to the ocean - i.e. keep the feed line full so the pump does not have to self prime (which as you very correctly state - it has zero ability to do). One could suppose the raw water should stay in the line from a 'vacuum lock', however with the speed and movement of the boat through the water all it takes is a slight 'air leak' and the water gets drawn out of the line. The siphon break is something Lagoon installed in some models and did not in others and I must admit I found this a bit odd, however, in the modification (new set up) we have the March Pump and its 'flow rate' varies on lift, so one way is to raise the lift (siphon Break) and lower the flow to match the Onan spec. for ones particular generator. I must say that we've still got it installed this way without any further modifications and it's literally been trouble free all these years - touch wood - lol. A very helpful comment Cheers for now Brent

[@SkypowerwithKarl]

I c

[@SkypowerwithKarl]

Catamaran Impi One other thing, the line from the though hull to the pump and four feet beyond the pump should be in a continuous slight incline. This includes the strainer. That is sometimes a challenge. I’ve had to use those flat low profile (pricey) strainers to accomplish this. I’ve even used a bronze street elbow between the through hull and valve to squeak down an extra inch. Not my preferred method. I’ve even secured the outlet side of the valve to prevent rotation or leveraging the fitting, a disaster. I’ve never done your mod for an engine, it’s always been done for heat pumps (AC) but you really got me thinking.

[@prof.m.ottozeeejcdecs9998]

Cool solution, Brent! Sometimes the designers should listen to the engineers, and get rid of unnecessary clutter. What interests me most is this: How happy are you with your LAGOON, and what do you not like or would like different or better?

[@CatamaranImpi]

Hi Prof - nice comment :) Perhaps I should do a video on your comment about the Lagoon and what we would do differently. We love many makes and brands of boats out there - our previous being the Catana 471 - and at the end of the day if it's safe, can carry all the home comforts and yield a passage of between 150 and 250nm per day, then it's a great boat for adventuring the world on :)

[@robertorzech7369]

Can I replace my impeller on my main diesel with one of those magnetic impeller pumps ? I have a brand new diesel engine that I'm installing in place of a gasoline engine. I would really like to reduce trouble and have one less headache to worry about. I think it's a great Idea.BTW I use a magnetic impeller pump on my aquarium and it rarely needs cleaning.

[@CatamaranImpi]

Hi Robert - sorry for delays in reply but busy sailing back to Noumea so writing to you underway. It is not impossible to install a magnetic style pump for raw water flow on your main diesel engines, however the system becomes complex instead of simple. One needs to consider the revs of the motor which varies, the flow rate at variable speed and voltage. This means you would probably have to build a 'controller' and to me that complicates instead of simplifies things. On the Onan after years and years of use we have never cleaned the pump due to the filter catching any debris and we have never lost an impeller. I hope I have not 'jinxed' my continued good service though by saying so :) I hope this helps and perhaps some other folks can share if they have done this. Best wishes Brent

[@robertorzech7369]

@@CatamaranImpi I never worry about how long it takes someone to reply.. That's the nice thing about email . with sailing , there's no need to be in a hurry. I will consider what you mentioned about raw water system on the main engine. One question before I let you get back to your sailing. Do these marine diesels allow water into the cooler exchanger and the flow be regulated by the thermostat or the speed of the impeller ? Do they have a thermostat like normal engines. I've got all winter to figure all this out. Thanks and Cheers Robert

[@CatamaranImpi]

Thank Robert - that's great The raw water side is purely sea water cooling and no thermostat. The raw water impeller is physically geared to the engine so the impeller turns faster and slower with the engine speed and as a result raw water / sea water pushes faster or slower. The raw water is sucked up from the ocean through a strainer by the raw water pump (impeller) through a cooler (tubes in the cooler isolate fresh water from raw water but allow heat to be transferred from fresh water to sea water) and then in most cases through a mixing elbow (which is where the engine exhaust gases evacuate and the raw sea water along with the gases). The fresh water has it's own separate pump and is in closed circuit similar to a car. Raw water flow (open circuit) could be thought of as a replacement of the radiator and cooling fan in a car / automobile. Depending on the mixing elbow design, the exhaust gases make sure to expel the raw water in the direction of flow of gasses, but in some cases if the pump were able to continue turning with the motor in off position, the absence of exhaust gas flow could allow the raw water to backflow to the pistons, so one wants to always make sure the pump runs with the engine. In the case of the Onan, the March pump is a 220v or 110v motor therefore AC voltage, and by wiring the pump to the AC outlet of the generator, this ensures the pump only runs whilst the generator is running as it gets it's power directly from the generator. I hope this helps Cheers for now Brent

[@douglasmontgomery6315]

Brent...great stuff man ! Question, could this be implemented for the main drive engines? They have the same issues

[@CatamaranImpi]

Hi Douglas - nice to hear from you again. The trick would be to match the flow rate of raw water and in this instance would require a 12v motor wired to only run when the motor runs.

[@douglasmontgomery6315]

Brent, understand. I don't think the flow rate is so critical. More is better right? :). In all seriousness, one could easily determine max flow (RPM of impeller @ max engine RPM), then just buy a 12VDC pump that flows at that speed. Flowing @ higher rate at lower engine RPM should not effect engine due to thermostat in cooling system. Tap DC motor off alternator or a latching circuit that closes a relay after engine starts. BTW, we call your cooler a heat exchanger in the US :).

[@CatamaranImpi]

Good point Douglas - the issue comes in at the mixing elbow where the raw water flows into the exhaust system. Depending on how that is set up one does not want water finding its way back to the motor or creating back pressure on the exhaust as that will result in carbon build up - not great for the engine :)

[@carmas54]

Great video ... and work ... well done 👍

[@CatamaranImpi]

Thanks carmas54 !

[@charlescurtius2261]

this looks like a brilliant solution to a pain in the butt maintenance problem. either i missed something or you didn't do the same thing on the engines and if not, why? is there some reason this same concept wont work for the boat's engines?

[@CatamaranImpi]

Hi Charles - It really does work well and certainly has saved us heaps of work. Our Onan was just not coping with the rubber impellers. I know they now put boost pumps on the feed side but why bother when the impeller can be removed entirely and one pump fitted! Anything is possible, including the main engines, however the trick would be to have a 12v pump wired to run when the engine runs. I don't think its necessary myself - the engine impellers generally are at sea level, sometimes below so the impellers last a long time. But sure - it's all about the flow rate of your raw water system and it needs to only pump when the engine runs otherwise you risk damaging the engine. Cheers my friend .... Brent

[@BobbieGWhiz]

So what is moving the raw water in the absence of the impeller? A magnetic device? How does that work?

[@CatamaranImpi]

Hi Bobbie - I am not an expert on magnetic drives, but basically as electricity is supplied to the magnetic field charge in the motor causes the impeller magnet to spin. The force is enough to push the rated volume of water through the system but if something were to block the impeller for example, there would be no shaft to break. They use little ones on water makers too (boost pumps)

[@CatamaranImpi]

Thanks Mal - been a while since we heard from you. I remember your engineering skills so lovely to have some input here. Hope all is well with you :)

[@CatamaranImpi]

Wow Mal - congratulations - that is fantastic man !!!! I hope your machine brings you many happy years of sailing :) We are in New Caledonia again - hanging off the hook at Mato tonight. I did some drone footage yesterday and today - posted it on our FB page if you'd like to see it - such stunning islands here. We should be back in Australia end of the year - thinking of heading down for Tasmania this year but things may change of course. Hope to catch up with you in Australia - we loved our time there - such friendly and generous people. Please do share some vids on YT and let me know when you do ... cheers my friend ... Brent

[@BobbieGWhiz]

Catamaran Impi Thanks, can you do the same for the main Diesel engines?

[@CatamaranImpi]

My pleasure Bobbie - when I next do a repair on this I will video it :)

[@SailingIdefix]

Great tech video, thanks for sharing !

[@CatamaranImpi]

Anytime Cyrille - we are not really into tech videos but I think it's worth sharing some tech stuff to help others along from time to time. Cheers my friend - wind is up - otherwise we would be flying that drone.

[@abatesnz]

Great video! Some of us will know what you refer to as a 'cooler' as a Heat Exchanger (moving heat from the sealed, closed-circuit fresh water system to the unsealed, raw sea water system).

[@CatamaranImpi]

Thanks for the info! Probably different countries and different terminology. I did my mechanical engineering with caterpillar and we refer to this as both cooler and heat exchanger. It's a great tip knowing that some folks only know this as a heat exchanger - cheers mate

[@abatesnz]

@@CatamaranImpi Oh, I read your blog post on how to fix the Lagoon 440 bulkhead problems before we crossed the Tasman to get back to New Zealand. I was told we only needed to fix the softness with everdure, but from what I experienced you want to make the boat as stiff as possible for Blue Water transits and glassing in the bulkheads would have been better. Your blog post was referenced by the marine surveyor.

[@CatamaranImpi]

@@abatesnz Awesome Andrew - fortunately the 440 doesn't have issues like the 450 has but yes, for world cruising its best to glass the outer sections in. One of the issues with catamarans is the flexing of the underside ahead of and behind bulkhead hard points - caused by slamming or wave action under the vessel. I hope you had a great trip from AUS to NZ - thinking to head back to NZ again as well ... maybe hook up for a beer ... cheers

[@JeffreyFay]

Is there a situation where the generator engine can be running but there is no 220v output to the raw water pump?

[@CatamaranImpi]

I guess if you have an issue with the generator output - yes for sure. At that point your raw water flow sensor would shut it down or your temp sensor .

[@RonnFolk]

The thing to remember is that this pump will add 2.36 Amp draw to your generator. If you have an under sized genset this added load might be a problem. That said these march pumps are great as a plus they are water cooled too.

[@stemtosternms4438]

I know this is old, but for those reading, It's my understanding the stock impeller takes more HP to drive than generating the amperage for the electric pump. But, as you say, it does eat a little gen capacity.

[@rodsilva80]

how can water get to the pistons (12:40) from the sea water pump? no way.

[@CatamaranImpi]

Rodrigo Feher yes for sure it can. If you have a restriction or blocked exhaust outlet with too much water flow water can back flow to the engine.

[@SailingAquamarine]

I have a spare electric water pump (actually a VW auxiliary coolant pump) that I keep should any raw water pump fail. I chatted with a colleague about why they are not used as standard. There are a couple of issues with it though: 1) The electric pump does not vary flow with the engine speed (e.g. faster running engine needs more flow) - this doesn't matter on a genset though 2) The jabsco impeller pump will run a much high pressure, a mag-impeller is low pressure - high flow. So if you get a blockage or restriction with the jabsco style impeller, it will likely push it through or just keep going where an electric pump will just stall In summary, as long as everything is clean, it's fine. But when something goes wrong the electric pumps don't have the head (pressure) to keep going. For me that's all fine as I only want it for emergencies (and having a spare electric pump on the boat is handy for so many things) I can monitor it carefully during the fix until I repair the original. But it is not quite good enough to leave 100%. Which is a shame!

[@CatamaranImpi]

Very interesting comment Charles ) I recall you making the same comment before. As you say it is not an issue with generators - ours running a number of years on this system, but yes, electric pump runs on 'voltage' not rpm. One needs to look at the variable allowed by the manufacturer. On the Onan we have never had a system stall, but then again we do keep the system maintained. The beauty is that there are ZERO rubber impellers to block the system and I really want to get away from these impellers altogether. The electric pump affords me that opportunity and is reasonably priced as an ongoing machine. The Onan folks in SA adopted this system after being in discussion with me - for some of their fishing vessels. They have made some modifications to leave 100% as the main raw water pump system - the workshop manager told me this helped them out a lot. Of course the suppliers of impeller type pumps are against this, but ultimately they are going to change to more reliable systems. This is a great system around impeller type pumps.

[@SailingAquamarine]

Well, lets face it, on the actual coolant pump in the engine it is probably an aluminium impeller pump not dissimilar to the electric one (it is direct coupled rather than mag coupled) but it is a guaranteed clean environment that will not need priming. I have used a lot of mag coupled pumps on ponds, the really big advantage of them is having the electronics completely separated from the wet bit :) they suffer from growth issues (green fur) slowing them down in that application though (but they are very easily cleaned) I must admit I am still at a loss as to the advantages of the jabsco impeller pump though, ok you don't need a valve with them, they are self priming, they handle 'dirty' water but they are awfully high maintenance compared to other pumps and most of the advantages have been solved in other applications. I have never seen this pump in a non 'marine' application! I don't buy the suppliers conspiracy theory, there is simply not enough money or a big enough market to justify it. the impellers are dead cheap as well! I know someone to ask, he is an ex-fireman and a sailor. He will have a very informed opinion but he is on a passage at the moment! I will return with his view later :)

[@CatamaranImpi]

No worries Charles - all good. Always interesting to hear all angles to modifications. On the Onan we were changing impellers less than 100 hrs and in the end 45 hours - some folks write to tell me they have the same issues. Everyone who has gone this route has written to tell me it solved their problem - including some of the technical people from Onan I shared it with. For me it was actually more about the effort and having to deal with keeping salt water out of the cocoon than the actual cost of the impeller. Cheers for now Brent

[@SailingAquamarine]

I think in your application (e.g. genset and nice clean raw water) you have a pretty much perfect solution. I have nagging worry about power circuit failure causing overheating, but there are other things to worry about in that situation! I am also trying to think about better ways to replace the raw water pumps on the main engine(s) I'm sure you replace the impellers on your engines every season and hate them as well!

[@CatamaranImpi]

Yes quite Charles - I would be interested if you do that. For me, the engines are a different story. It would require 12v pump and rated to run within the min max flow rates for the engines rpm's. It feels more complicated to me and due to the Yanmars sitting at water level we have not had a failure on the raw water impellers in 6 years of cruising :) So for me, where I don't have an issue I don't feel a need to modify. I also think that if the Onan was positioned at water level it would not be such a problem. As for your application, can you not fit some sort of flow sensor that shuts down the pump in these ponds if you have a circuit failure. I know on my farm, the borehole pump had these issues - man - cost me a ton of money each time and that pump sits 80m below ground level. Eventually I fitted 'full and empty' sensors on the pump so it would turn off when the water was being depleted. The cost of that saved me a lot in the long run.

[@pjweir9220]

Kubota engine. Is it a 1005 or 722 ?

[@CatamaranImpi]

PJ - good question - I think we have the Kubota D1005 BG but would have to check those numbers that are swirling in my head ...

[@stinkintoad]

That should be applied to the main engines also. Great idea.

[@CatamaranImpi]

I guess one could do - but one would have to check Raw Water Flow rates for idle verses high revs - see that it can cope since this would need to be 12v and is not a positive drive pump delivering according to the RPM. It would also need to deliver ONLY while the engine runs ... Cheers for now Brent

[@karensteveonola6014]

@@CatamaranImpi ​Would a constant flow really matter on the raw water side? Dare I propose spec. a pump for the high rev flow and let it go. If one could find a 12VDC (or whatever your system is) pump, driven off the engine alternator, that could meet the upper flow values for the cooler, the thermostat on the "fresh" water side would handle the flow variation (higher than normal) at idle for temperature control so the raw could be constant. Am I missing something here? Sorry to come into this late, my captain (Karen) and I are just starting our adventure this June on a 450s and I so want to get rid of all impellers

[@snakeplisken4278]

Very nice! Thanks for sharing. Boer maak 'n plan!

[@CatamaranImpi]

:) Pleased you found this helpful and yes, Boer maak n plan ...

[@OurLakeLife]

Brent, great video! Thankyou for sharing! I am going to do exactly this on our boat. What a smart idea! I am curious, does the generator have some impeller that circulates the "fresh water/anti-freeze" thru the engine block? The reason I ask is that I recently fiddled with the mechanical temp switch (that restrcts the raw water from flowing) and ever since are having problems with the genset cutting out after a few min of running smoothly. Everyone, keeps telling me I may have an air bubble or some impeller piece blocking the line (however, the exhaust is spitting out water perfectly when it does run). I am wondering if something else may be broken and that it doesn't even ciruclate the water inside to reach the exchanger. You can see a lengthy discussion on everything I tried below. Curious if you have any perspective on it? Groete van huis tot huis. Heinrich forums.montereyboats.com/index.php?/topic/1978-genset-kohler-5e-overheating/#comment-5061

[@CatamaranImpi]

Hi Heinrich - glad we could share this with you - I can now refer all folks who write to ask me about the modification to a video :) I am at sea now so can't read the discussion link above - also excuse spell errors and typing - not easy in the moving ocean - I read the link later - but let me give you some ideas in the meanwhile that I would be looking at ... I assume you have checked the system by by passing the sensor you were tampering with when it failed? The fact you were tampering with he sensor may be co incidental but is obvious to check that out first. I will offload a few ideas here … The Fresh water reticulation is driven by a water pump that is propelled by the fan belt. As mentioned in the video it is closed circuit so has nothing obviously to do with the water you see spitting out of the exhaust. That is Raw Water, and if your raw water flow is good then at least you have that. First step - does your generator display an error code? Not sure which genset you have - lets assume similar to mine … If Water Flow error alarms - but you can see good raw water flow, then by pass the sender unit temporarily to see if it still shuts down - it should not. The flow sensor can become blocked (scale) and can be cleaned out with a thin object. But more about this if the error code is Raw Water - I think it is code error 7 if my memory serves me correctly. Second step - if there is no specific code error - Check the tension on the fan belt that drives the water pump (of course you have also checked that there is no external leak, that the water expansion tank is at level and also the 'radiator tank' is full (remove cap when engine is cool) - and all clamps are tight. As a side note: If you replaced fresh water and coolant somewhere along the line - by switching coolant types (anti freeze) you can create heating problems since, for example green and red coolant do not work together and can form a 'grunge' in the system, so assuming you have not done this. If you have, you will need to drain the system entirely and fill with fresh water and soap liquid like Joy - then run the system till warm and drain everything again. You now top off with the correct coolant type and mix ratio (water to coolant on Onan 50/50) If you are sure the fan belt is at correct tension, the other things I mention above are correct, then there are a number of things to look at - one of them being: a. Air in the system. If you filled the system too quickly somewhere along the line then it could well be that there has been an air lock in the system and yes, this will cause overheating and although the system may look to be filled with water, there may be an air pocket moving back and forth that cannot escape. I would go ahead and drain the system (radiator cap removed of course) instead of trying to bleed it through the block bleed screws - fill again VERY SLOWLY or even better you can fill from the bottom up 'slowly' (again radiator cap is removed) where I mentioned this in the video. b. Thermostat. To test this, you can simply remove the thermostat entirely and test again without the thermostat in place. The thermostat is important for maintaining a certain level of temperature which is good for the engine - ESPECIALLY in colder climates. In Hot climates one could remove it entirely, but best to have it there anyhow. If the thermostat is faulty, it could be that the valve does not open to allow circulation at the specified heat. (I can't remember the value for the Onan but it would be at around the operating temperature suggested in your handbook. c. Radiator Cap The radiator cap is like a breather. It maintains a certain pressure in the system and should actually be changed around every 1000 hrs to be sure. d. Cooler blockage. This is unlikely but if you did not have coolant in the system (anti freeze) and depending on the fresh water used, you can get scale build up. This can coat the outside of the tubes in the cooler and reduce heat transfer properties from fresh to raw water. If this is the case (usually in fresh water with too much calcium or lime) you will need to do several flushes with Joy Soap since lime may also coat the engine block where the fresh water runs and this will hamper cooling properties. The cooler in this instance will also have to go to a radiator shop for cleaning. Do NOT place the cooler in pool acid like some folks suggest on occasion - if you leave it there too long it can eat through the tubes. I assume you have checked for 'kinks' in the tubes and the obvious issues. Also, for good measure, just check where the rubber tubes go into / out of the fresh water pump - sometimes that little tube corrodes (not seen easily) or cracks - I have had to replace that copper tube into the pump and actually carry spares with me for it. Lets start with this. Please let me know how it goes.

[@Swizzenator]

Brent is correct about the raw water flow sensor possibly the hole where it screws in being block with small particles. Yes Brent 7 flashes is a no or low raw water flow issue. I just removed my heat exchanger for cleaning and the hole for the raw water flow sensor was blocked by debris. You can bypass the sensor by removing the 2 wires that go to the sensor and jump them together to bypass it. Just make sure your getting proper water discharge when shes running. I have an Onan 11k MDKBN.

[@CatamaranImpi]

Correct my friend - That will CERTAINLY stop your generator after starting up. Bypassing the sensor depends on open circuit or closed circuit sensor. This means either the wires must be joined or be apart depending on which you have. You can safely run the generator without that flow sensor in the meantime AS LONG AS the water flow at the exhaust is strong. In the flow sensor - yes, where is screws in you must clean out the debris and if this does not work you must buy a new Raw Water Sensor. It can save you lots of money so be sure to get that sorted for the long term. I am pleased you are having the cooler cleaned - usually when the sensor is blocked it means you have a build up of material and this could pac into the tubes over time - so - well done - You are on the correct track! Brent

[@CatamaranImpi]

Sorry Mike and Heinrich - getting confused with the two comments at first thinking all from Heinrich, but at least this will clear that up. I am pretty sure the sensor has something to do with it.

[@OurLakeLife]

Guys, thanks for all the feedback! I'll try to get down to the dock this weekend and see if I can make some progress on the issue before the winter arrives (next Brent will likely post a video of him sitting on some beach soaking in the Sun) -joke. Again, guys thanks for all the advice. I'll keep you guys posted - hopefully soon (having heat certainly extends the winter season a tad). Like they say in Afrikaans (my boere taal) Baie dankie. (Thanks).

[@henningneuse9365]

well done - will discuss this on our solar-yachts. Cheers from www.yachts.solar

[@CatamaranImpi]

Hey Henning - Thanks my friend - yes certainly and especially with your beautiful yachts where the generator plays a bigger role than on most - would certainly be throwing out the impellers :) Cheers for now Brent

[@CatamaranImpi]

PS. Have you guys finished building my boat yet?

[@henningneuse2909]

Actually our generator plays not a bigger role than on these conventional boats with combustion-engines and sails. We have NOT need the generator for thousands of miles - solar-e-cruising 24/7 !!! Anyway, it is important to have one, and impellers are always a pain. Again, a great job of yours! .... Which of "your" boats do you mean? :) Production time of our 55ft solar-yachts is 8 months. Shall we begin with yours, too? kzbin.info/door/FXNKOTS6I_qoc2tlsRVVBw Cheers from sunny Germany

[@CatamaranImpi]

Yes Henning - I need one of these Solaryachts before everyone understands this is how our future is going to look in world sailing :)

[@lauriedavis6344]

And I thought my motorhome was complicated!

[@CatamaranImpi]

Hahaha - good one JP - except when you jump out of it you don't get wet :)

[@jandradventures]

Well done video! Thanks for sharing!

[@CatamaranImpi]

Hey thanks you two - you guys are great !!