Building a Small Cruising Catamaran Episode 3

[@PartikleVT]

That hull is huge, this is gonna be epic. I was planning on something probably half the size myself

[@davidmccauley7068]

@@PartikleVT what do you have planned!?

[@PartikleVT]

@@davidmccauley7068 hull designs so far and overall dimensions, 2.3m beam, 5.5m length (possibly longer) so that LWL ends up at 5m, BWL at 0.5m for each hull, giving us a LBR of 10 which is not that fast, but plenty fast. Going with 0.5BWL for each hull so I could possibly fit inboard motors for each side with hopefully jet propulsion. The motors are not decided yet, but are easy to configure after the boat has a shape because I am marinizing my own motors for it. Planning on diesel, like the 1.9tdi vw (that vw marinized as well and sold under vw marine). Now that is probably definitely too big for the full, which is why the hulls need to be tapered, but only above the waterline in order to maintain a LBR of over 8. That way the motors will end up sitting way higher, which im not a huge fan of, but the solution would require a belt drive to the jet anyway, because I am not going to spend money on some hamilton jets, but rather use a jetski jet with a appropriately designed inlet (even though I hate hydrodynamics, but I'm willing to crunch the numbers for this one time) which leads me to a problem, the jetski runs at 7500-8000rpm and diesel motor is 3500-4000. so I need a 1:2 gear ratio, which is quite easily achieved with a heavy duty belt drive. So I'm going to have to introduce said powertrain anyway if I want to use jets in say a monohull, so its actually not a catamaran specific sacrifice at all. There is always the possibility to go with bit wider hulls but that increases the length 10x if I want to maintain the LBR. Given the complicated geometry this leads to, I'm still stuck in CAD with the project. I'm trying to maintain specifically the 2.3m overall beam because of trailer legislation, that being the max width. If not feasible, its not actually a big deal, I do have a property with a waterfront, but it'd need modifications to accommodate a dock. I'm using the catamaran design formulas by Terho Halme in this, those can be found in catamaransite.com. I wanted to ask you about the hull shape, is there a specific reason you ended up with this exact shape, did you use some kind of formula to determine the angles etc.?

[@PartikleVT]

oh and given the difficult shapes im going for, I'm probably going to have to divide the plywood structure into triangles for easier bending and shaping

[@PartikleVT]

and I just saw aquila have fitted their power cat with a hydrofoil, so we'll see if that ever makes it into the plans, but probably going to build fittings for it so its modular if I ever make one

[@imac1912]

Hi, your video appeared on my feed and I was interested because I have built a few boats using fibreglass - one of them a catamaran. However, you really need to get yourself properly equipped to do this work. As a few previous people have commented on - the safety equipment for your own and others including the dog's health. Measuring out the correct proportions when mixing etc. I have subscribed to follow along but take some time to get yourself the right equipment and safety gear.

[@davidmccauley7068]

Feel free to send me some stuff, including a dog respirator! Thanks!

[@kathleenmccauley579]

Cool!

[@kankama1]

Gday - this just popped up on my feed and I don't mean to be mean, but I really hope that is not colloidal silica you are using as a glue mix. If it is I hope that out of shit you had a respirator on. Silica is great stuff but does produce silicosis. So if it is you keep safer by wearing a good mask- like a Sundstrom. Good luck on the project.

[@RifeBoatworks]

Cool project. How do like the System three?

[@davidmccauley7068]

Thanks! It seems to be okay!

[@BradleyBellwether-oy2qi]

I'm glad you were wearing a respirator at least some of the time, but you let the dog be in there breathing it? You know what it can do to your lungs. But, the dog laying with its nose on a floor full of glass and resin dust doesn't know any better. It just wants to be around _you._

[@joshkaiser8583]

Any more progress videos?

[@davidmccauley7068]

@@joshkaiser8583 just had baby number 2 hadn't had much time to get to the shop unfortunately...

[@joshkaiser8583]

Gotcha totally understand that one! Congratulations hope you bride and little one are doing well

[@davidmccauley7068]

@@joshkaiser8583 thank you!

[@jeffreylord8172]

get a set of scales and then weigh the resin , much more accurate and you only need 1 container, packing tape on strong back stops glue sticking

[@davidmccauley7068]

Thanks for the tip!