Goodbye Bronze! Upgrading Our Thru Hulls

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We'd already started noticing some corrosion with our bronze thru hulls, so in our mission to eliminate potential points of failure, it's time to upgrade! All of our old thru hulls get removed and massively upgraded with Marelon thru hulls, Marelon scoops, Marlon seacocks and fiberglass backing plates.
This started out as a project we weren't 100% sure how to do, but a little faith in ourselves (and a lot of helpful advice from friends!) and we're absolutely thrilled with the result!
We definitely recommend this resource if you want to try and tackle this project yourself:
marinehowto.co...
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[@PA96704]

Make sure you have plugs for every thru hull on your boat ready from the outside bottom to inside hull.

[@corkson1744]

Nice! An important job well done 👍. I’m saving/bookmarking many of your boat work episodes for when I’ll probably be doing similar on my boat. You are an inspiration, and your quality of work sure seems top notch. Thanks for sharing. RESPECT ✊

[@OutChasingStars]

We greatly appreciate the compliment! Boat projects are a lot of work, but it feels very satisfying when you're done and know you've made things better than they were before.

[@matthewkorwel1099]

Wow, a whole lot of able seafarers commenting here who are certain that `new` things don't work. When all these folks are done arguing about why composites (the same material as the hull) are bad, you might want to tell them that boats now-a-days also have engines, batteries and even fridges and freezers. They'll be mind blown. Thanks for the great video guys, I'm this week upgrading mine to tru-design. Cheers!

[@miked5563]

See you next month! Annapolis 2024!!

[@david_shih]

dude, double hole saw....genius!

[@OutChasingStars]

I'm a big fan of the "work smarter, not harder" philosophy... 😂

[@verne5770]

It is a beautiful thing when a plan comes together!

[@1Tane55]

Oh yeah the bronze is a problem , it only lasted 40 years. Can't have that, ha ha ha.

[@gidge34]

Good job 👍

[@pleclerc1]

Awesome video guys, i learned a lot :) Quick tip, when caulking, use soapy water to clean your bead, it will not leave a mess and make it look really nice.

[@lowellmccormick6991]

To quote the not so famous ancient Greek machinist, Mediocrates, "good enough".

[@OutChasingStars]

😂 I can accept "good enough" when it comes to the visual appearance of things, but it still has to function properly!

[@mstuart1]

I can't believe you called this an upgrade. bronze is much stronger and has a much longer life. Plus the insurance will not go for this. I have an Offshore 48 with twin Cat 3208s 1988 all seacocks and thu hulls are bronze. when properly maintained they all work great. I am curious what gave you the idea to go to marelon? I don't want to be negitive I just want you to know the proper way.

[@mindebrolis9582]

Insurance will go with it, it is not just plastics. It is composite materials that are both stronger, more flexible than bronze and do not oxidate/corrode.

[@MikeSantis]

There must be a good reason that so many go for Tru-design composite these days and not bronze.

[@matthewkorwel1099]

Um, what are you talking about? Bronze is not 'the proper way'. Composites are 1. stronger than the bronze an aluminum 2. will last longer than bronze 3. don't have to worry about electrolysis or bonding. If you have a fiberglass/carbon boat these compsite thru hulls are literally the same thing as your hull. To anyone else reading this, despite this persons confident outburst, rest assured he is sharing bad information.

[@dboboc]

People have no problem paying more money on unnecessary equipment like the latest electronic gadget but don’t want to pay for proper bronze seacocks.

[@matthewkorwel1099]

@@dboboc who said anything about money? Literally bronze is the inferior product for all kinds of reasons that have already been listed.

[@6800891]

Never dealt with through hulls begore but if sinking is a big risk, why not route all water access over the side or back of boat using pipes and therefore have no holes at all in hull?

[@hotttt28]

Ear protection,air mask ?

[@dougmarder]

Step wrench: do they make different ones for metric and imperial? "Kittyhair": I have not seen anyone else use this stuff before. The only images you show are of the back of the can. Is it a filler? Can you tell us more about this product and whether you have used it anywhere else? Seacocks: can you tell us why you chose that brand / model? They are clearly beefier that the FP factory installed models, but it looks like a lot of plastic to go into some small spaces. Are they Marelon too? See you both in Annapolis!

[@OutChasingStars]

I know there are various manufacturers of step wrenches, but not sure about imperial vs metric. Kitty Hair is a fiberglass filler by Evercoat that was suggested as a backing plate mount product in the Marine How To article. We'd never used it before and decided it would work better to mount backing plates without the center hole already drilled. It wasn't quite as 'spreadable' around the hole which made threading the thru-hole in during our "leveling" step harder. The entire seacock/thru-hull assembly is Marelon. And we went with their special OEM series which is used by boatbuilders. This is the most compact solution they offer but any seacock will definitely be bigger than what FP does from the factory!

[@aubreytycer8708]

So totally complicated. KISS for me.

[@acampbell198]

Looks like you started quite the debate on bronze vs Marlon and a sub debate on whether your old fittings were brass or bronze. Great video! I recall that you all are moving away from KZbin and have other irons in the fire you are tending. Good luck on those new endeavors and thank you for all the great content. One question concerning your project, I noticed you took all the paint and barrier coat off when replacing fittings...required for bedding compounds to mate to gelcoat and not paint. But then you put strainers over the through hull fittings leaving bare gelcoat exposed under the strainer...or so it would appear. Are you concerned at all with this little bit of gelcoat being exposed under the strainer w/out any barrier coat and/or ablative paint? I will be doing this same project this fall and am trying to learn all I can from those who have already done it. Again, thank you!

[@michaelbeasley2085]

As a life long boat builder, what you are doing couldn't be further from correct. I would absolutely never replace bronze with plastic. Especially below the water line. First off what your doing will not even pass an insurance inspection. Anything below the water line MUST be a seacock, with a thru hull threaded into the second with 3 thru bolts through the hull. Then it should be tied into the bonding system of the boat. Plastic thru hulls should be illegal period. The only caulk you should be using is 5200 by 3M. Blue label takes a week to dry but the red label is ready to launch in a few hours. Plan on replacing the plastic crap in about 5 years if they are even still on the bottom. He'll a pressure washer will destroy them. Good luck.

[@OutChasingStars]

Fortunately, we didn't replace bronze with plastic. We replaced everything with Marelon which is fully A.B.Y.C. approved. And not sure if you watched the whole video, but we didn't actually have seacocks previously. We're quite pleased with the upgrade and are confident the new fittings will hold up just fine.

[@sparkeyjones6261]

@@OutChasingStars Forespar likes to call it "a proprietary formulation of polymer composite compounds using composite reinforced polymer and additives". That's a fancy way of saying carbon reinforced plastic. lol They're not completely maintenance free, you should definitely service them regularly. I've read about far too many incidents of failure in these things to be comfortable with them myself.

[@michaelbeasley2085]

@@sparkeyjones6261 That's what I was trying to tell him.

[@sparkeyjones6261]

@@michaelbeasley2085 I know, just thought I'd add my own two cents. 🙂 It's highly unlikely anyone would break off the handle on a Groco BV seacock, but I've heard plenty of stories where it's happened with the Marelon ones.

[@willyum1208]

5200 on a thru-hull? never

[@podocrypto6072]

The fiberglass backing board was not a good plan for the future. Getting a good bond to the hull, with gelcoat still in-place is difficult). Instead you could have grinded the gelcoat off the inside bottom of the hull and then tabbing in a couple of 3-4" strips of 1708 bi-axle tabbing strips using epoxy, would have be a better solution. Then once cured, drilling a center hole from outside of the thru-hull hole with a 1/4" drill thru the tabbed glass inside, then use a standard hole saw bit to bore the holes to exactly the size that you need for the new thru-hull fittings. And speaking of thru-hull fittings, that blue stuff that you called corrosion is the bronze doing it's job to protect the bronze metal fitting. You noticed the shiney surfaces once you removed them? Well you can bring the entire fitting back to it's original glory by bring it to a "brass" wire wheel (steel wire wheels are too harsh on bronze or brass) and removing the blue stuff and mild outside patina. Also use a round bottle or pipe brass wire brush on a drill to clean up the inside of the bronze/brass thru-hull fitting. THEN (additional tip) clean with acetone and paint them with "Speed Prop" and allow it to fully cure before re-installing them back in the boat. Personally, I don't trust plastic thru-hull fittings (they can break easier). An example of that, where you can go look up, is when a specific episode of Sailing Zingaro when he refitted his Oyster with plastic thru-hulls and one of them cracked and almost sunk his boat boat on it's maiden voyage at his first anchorage.

[@SOLDOZER]

Zingaro is a clown who did not properly install the the thru-hulls. He just gooped everything with 5200 and hoped for the best with no load bearing collars. He did not even install the strainer the correct direction. Im shocked he did not hydrolock the engine. Also it was a speed sensor that popped out and flooded. Not a seacock issue.

[@jasonsteele6196]

There is some good information in the video but good grief this guy is dramatic.

[@HeLaNoR]

Sorry mate but i wouldnt change bronze over plastic either, whatever is reinforced with.

[@matthewkorwel1099]

curious if you know what the rest of the boat is made of?

[@HeLaNoR]

@@matthewkorwel1099 Sure i know i was working on the industry. Its fiberglass. Probably aircured that means it is always curing. Has a lifespan of 30-40 years depending on the fatigue and uv exposure. The difference in the haul and a fitting is that a fitting has a very small stress area compared to a haul. A brass fitting will last a lot longer than that, a fiber reinforced plastic.... i dont think so. Anyway everyone has his own opinion but in my boat i would never change a brass fitting for ANY composite material. I've seen aerospace composites failing in applications where brass was a simpler cheaper and better in every way.

[@luizdesousa7079]

you put your life on plastic vs bronze. "kind of stupid"

[@captlarry-3525]

The step wrench is not for tightening or loosening!.. you hold the sucker stationary while the wrench on the inside does the work. Cutting the putty is fine, but a block of wood and a hammer breaks it out with no gouging the hull by prying.

[@howtodave1725]

I am from Baytown, TX. I have worked on Heavy Equipment for longer than I want to say. The best wrench for tight spaces with a large jaw is a ford wrench. Get one you will not regret it.

[@OutChasingStars]

Good tip, thanks!

[@joedirt9600]

Good day sir, I never heard of a Ford wrench before, did some research and will definitely be purchasing one. I am a boat owner and working space is very confined. Thank you

[@howtodave1725]

@@joedirt9600 I have used it as a pry bar when tightening belts on a motor. I have use as a hammer. Slide a pipe over the handel for extra leaverage. I hope it serves you as well as it has me.

[@Malibus_Most_Wanted]

Deep sockets are life lol I only use the wrench when I don’t have the proper socket n usually end up buying the socket size needed

[@jima4656]

Bronze thru hulls are supposed to be bonded to a zinc anode. Failing to do that will cause the type of galvanic corrosion that you saw.

[@SMM-Mystery]

Why would you get rid of the time proven bronze through-hauls?

[@SMM-Mystery]

No fittings on a sailbost that go through-hull are brass.. they are Bronze

[@OutChasingStars]

A very large part of the career I made was asking the question "why?" when I was told something had always been done this way. Time proven is good, but that doesn't mean there isn't something better that exists now. Marelon won't corrode and adding seacocks with the fiberglass backing plate is a significantly stronger solution than what we had perviously.

[@Timothy-xd]

Love these videos! Keep up the good work :)

[@ukyachty]

As I said in my previous comment the removed fittings were just brass. You could have saved yourself a ton of money and made the job significantly easier by using DZR fittings

[@ukyachty]

Two things: a. the corroded fittings were not bronze - not even DZR, just brass. b. we use an angle grinder to cut away the skin fitting from the outside and then tap it inwards.

[@rski1036]

The best way to deal with a boat yard is a pen to sign the work order and provide your phone number for them to call when the work is complete.

[@davidfritch6954]

West systems six ten is an excellent adhesive for the backing plates. I prefer groco flanged seacocks with their premade backing plates.

[@captlarry-3525]

Get a bigger hammer 5lb short handle sledge

[@kevinhoffman8214]

I would put the bronze back in , the plastic will break in a freeze

[@mindebrolis9582]

Normal composites today easily stay “flexible” in -40deg C and are more resistant to hits than bronze

[@oldergeologist]

My experience is that bronze is the best physically strong and virtually impervious to corrosion. My 42 year old Peterson 30 through holes are as good as new.

[@Topiflex280]

It is not plastic. It is a glass-reinforced nylon composite. It is a big difference. have switched to truedesign years ago - no more bronze crap again.

[@kevinhoffman8214]

@@Topiflex280 good luck with that

[@wooly1286]

​@@Topiflex280what is nylon ? Last time I checked that is plastic and yes it's fiber reinforced which makes it stronger. But still plastic if it was my boat keep the bronze.

[@svamour4574]

Thank you, David for sharing your knowledge. This is my next project on my vessel.

[@jamesstrom6991]

some keep bungs stringed to their seacocks…

[@jeffdege4786]

I've never trusted threading into fiberglass.

[@MondoRockable]

Not quite following what the technique here is for torquing those through-hulls? Did I misunderstand your approach, that you didn't want to torque them all the way down because you wanted a sealant gap between through-hull and hull, just letting a small amount of the sealant "squeeze-out"? Is that a recommended process? What should those through-hulls be torqued too? Can't imagine your technique here is correct.

[@hotttt28]

Ear protection, face mask ?

[@bill2292]

Why did you need to add backing plates?

[@OutChasingStars]

The backing plates add some extra strength and rigidity as well as give me something to screw into that isn't the hull of the boat.

[@Skipper864]

Ah, there's the answer to my question. I figured for strength but didn't consider the screws. I also now understand "kitty hair" bonds the fiberglass backing plate to the hull. Well done!

[@TheCorsair]

Typically these french boats do not use bronze. Rather they use chromed brass which is far less robust.

[@OutChasingStars]

All the more reason to replace!

[@AndyKopac]

Huh. Never seen anybody remove a thruhull like that. Always ground the outside flange down and popped it thru….

[@tracyoliver550]

Looking at the same job in the next season or two. Any concern using the heat gun and deteriorating the glass? Thanks

[@willyum1208]

glad you didn't bolt threw the hull like your linked article does, much better the way you did it.

[@22South]

This guy looks like my King Neptune representative!!! You guys rock!

[@OutChasingStars]

King Neptune must have a favorite helper he keeps sending us! 😂

[@trojan440]

Bronze needs to be bonded from any stray electrical current,thus the rose color.

[@cmdmd]

Yup, those seacocks need to be in better shape. You dont want to pull an Oceanos.

[@humanafterall2076]

Your old mate Stanley is always on hand. Hit it hard coz he does that best.

[@timcampbell6008]

Holy through holes batman. Nice job!

[@bazonis1gp]

👉❤👈

[@1DesertCop]

I hope all those plastic thru holes hold up

[@mikeferguson2828]

Easier to cut off the inside of the thru hull with an oscillating saw and tap it out from the inside . I don’t like using heat near gel coat. Personally I prefer the New Zealand Tru Design thru hulls and stopcocks. Leopard use 2 inch forespar ones on our toilet outlets and down the road they always seem to drip from the handle. You need to take the handle off and change the o ring and silicone grease it well and put them together again. I have not as yet had a drip from the Tru design ones. As you are using marelon you could have epoxied them in place. Certainly better than sika long term. I did that to my boat. One day if the need changing you just use the hole saw .

[@OutChasingStars]

I do like the Tru Designs as well, but they're a bit harder to find in the US!

[@jackweston7530]

welcome back admiral

[@mickharfield6907]

Another Great Video 👏 Great Job Dave, love your last comment in the video "But We figured it Out" the best way to learn is to give it ago 👏 Mick & Nikki

[@OutChasingStars]

I still fight that nervous feeling of "am I about to screw this up even worse than it was before?" but you just have to go for it!

[@Chris-zo5ze]

Loving the boatwork series. Quick question... Who made those LED headlamps? I need one!

[@OutChasingStars]

They're called Lightbar Headlamps. And they're awesome!

[@pubstomperplays]

progress looks good!

[@TPLeary]

Nice job, G10 is a great product Been using it for years

[@OutChasingStars]

It's the first time we've had a need to use it, but it worked really well!

[@robertkrchnavek6450]

Very nice work!

[@OZ1DK]

Bad design seacocks

[@pubu2010]

Replacing metal with plastic is not an upgrade. Below the waterline, bronze is the industry standard. Definitely someone working on a boat for first time. In a decade or so doing this work, will be qualified to make these videos properly.

[@mindebrolis9582]

Replacing metals with different composites it is exactly the practice in all the industry. From boats to space-ships….

[@sailingchasingsummer9729]

Marlon is not an upgrade. And when it comes to thru-hulls, if you plan going away from the dock, us a proper flanged seacock, thru-bolted from the outside.

[@SOLDOZER]

Heat gun and putty knife??? CRINGE. Just stop dude....get some real tools.

[@blondestrainger]

It’s not that they won’t work but expansion of plastic and it cracks you sink , can’t tighten like bronze

[@blondestrainger]

Ask your insurance company and Lloyds first

[@chachi1970]

I will never trust a plastic through hull fitting again. I hit a small log at slow speed and it snapped the plastic fitting off the outside of my hull and almost sank my boat. Bronze or stainless would have taken a peice of the log. No plastic below the waterline...ever

[@matthewkorwel1099]

Are you saying bronze thru hulls never break? I know of 3 boats personally that would disagree with you.

[@jkutyna]

You got rid of brass not bronze.

[@chachi1970]

wrong! boats use bronze, not brass

[@maus0292]

I don’t understand why plastic/ glass over bronze? And hopefully you have the right size bings for the holes if they ever break.

[@OutChasingStars]

The new thru-hulls and seacocks are Marelon. They're not "plastic" and are definitely a marine rated solution. They're plenty strong and we'll never need to worry about corrosion again. And the seacocks we got actually come with an emergency thru hull plug as a cap in the handle.

[@mindebrolis9582]

No more oxidation and corrosion…

[@james412m]

Great video. We upgrade to marlon about6 years ago. So far no issues and I expect to have no issues in the future.

[@christopher-bj8de]

Remove bronze ( or are they DZR Brass?) and replace with plastic 🤔See you back here in 5 years when your insurance company tells you you have to replace all your plastic seacocks.

[@OutChasingStars]

I've been seeing several comments like this so I'm genuinely curious. Why do you think there will be such an issue with Marelon? We have the Series 93 seacocks which exceed ABYC standards and have official ISO certification. We won't have any issues with corrosion or electrolysis, which are issues we were already experiencing with our old bronze (or could have been brass, not sure...) thru hulls. www.forespar.com/pdf/techTips/M10-Marelon-Marine-Grade-Plumbing-Systems-with-certificates.pdf

[@christopher-bj8de]

@@OutChasingStars I would say that there's a reason insurance companies never insist that bronze seacocks are changed just because of there age whereas (at least on this side of the pond) they are recommending plastic be changed after 5 years. It may be wise to ask your insurance company?

[@OutChasingStars]

Our insurance company has told me that any big changes to the boat must meet ABYC standards so we're all good on that front. There are quite a few boat manufacturers who use Marelon as standard over bronze so hopefully any insurance qualms about Marelon (which is definitely different from basic plastic) have gone away.

[@christopher-bj8de]

@@OutChasingStars Great mate , get it in writing 😎

[@rray3630]

There e is NO UPGRADE from Bronze as underwater material choice .