Self build catamarans designs

[Row Bear]

Wharram cats are probably the easiest to build
In 1980 my partner launched a Narii mk 4. All wooden components were given 3 coats of West epoxy. After sailing the boat out the St Lawrence to the carribean and bsck I sold her. The boat.is still being sailed and providing enjoyment to its owners.

[daletournier]

Originally Posted by 44'cruisingcat

Have a look at Peter Snell's designs.

Mike Waller is worth a look too:

http://www.wallerdesign.com.au/

Edit: Peter Snell may have retired. Can't find his website.

I met with Mike Waller at his house years ago when I was thinking of building one of his boats, only my personal opinion, but I thought his designs were much better in a number of ways when compared to Peter Snells.

Personally I think people underestimate the time and cost of building a ply wood boat. I spent 8 mths in a boat yard restoring an old Wharram. In the shed a guy was building a beautiful tiki 38, fantastic job BUT it took just as many hours to build as a Cat like yours and I would suggest it was no cheaper to build (dont know that for sure). I believe James Wharram was responsible for giving people the impression they were cheap and easy to build....it may depend on the standard one wants I suppose.

[daletournier]

Originally Posted by blubaju

I built 2 cats, first stripplanking/ply in West system, far to heavy, second a set from Schionning design/Australia, this balsa core is fine, your size I would look into Fusioncats.com they are 12m or 40' come in prefinished, (including paint!!!) parts in a container. No risk on overweight, no problem w quality surface, assemble, fit out & sail away. And no, no ply

I looked a schioning arrow while in South Africa, flat pack build that fits in a 40ft container. It was impressive to me.

[daletournier]

Originally Posted by Simi 60

Then you get these type of plywood cat for sale for $1million usd

Dudley Dix DH550 Catamaran for sale by owner

That thing is boat porn, I regularly google it.

[daletournier]

Originally Posted by Fore and Aft

The one thing about plywood and the reason I like it is that it is a nice material to work with. That is a big factor when building a boat.
As for resale value the most expensive plywood cat in Australia I have surveyed sold for $250,000. Just check this link out for plywood cat prices.
https://yachthub.com/list/search.htm...rency=&poa=yes
As for plywood yachts check out the RM website. They are good looking boats. Did I read another post Dale where you said you had been on one?
Fora Marine - RM Yachts
Cheers

I was on an RM in Brazil ,seriously cool boat, loved the interior design, very modern and functional, I also saw one out of the water, very flat bottom, to flat for me.

[44'cruisingcat]

Originally Posted by daletournier

I met with Mike Waller at his house years ago when I was thinking of building one of his boats, only my personal opinion, but I thought his designs were much better in a number of ways when compared to Peter Snells.

Personally I think people underestimate the time and cost of building a ply wood boat. I spent 8 mths in a boat yard restoring an old Wharram. In the shed a guy was building a beautiful tiki 38, fantastic job BUT it took just as many hours to build as a Cat like yours and I would suggest it was no cheaper to build (dont know that for sure). I believe James Wharram was responsible for giving people the impression they were cheap and easy to build....it may depend on the standard one wants I suppose.

I agree with all that. Surprisingly Mike Waller's designs aren't well known.

On the face of it, you'd expect a ply cat to be much cheaper, marine ply being say $120 a sheet, vs DuFlex at around $500 a sheet.

But by the time you've glassed and epoxied the ply, the difference is a fair bit less. Then consider how much stronger and lighter the DuFlex is....

And the hull/deck material is only part of the cost. The cost to fair, paint, fit out, rig, fit engines etc is the same.

My boat probably would have been cheaper in ply, but in reality only by maybe 10 - 15%

[Thumbs Up]

The five berths and standing headroom is a tall order (depends on how tall you are though). If you are seriously going to build a cruising cat you should buy plans from a reputable modern design or buy a kit and to have good resale value it should be foam sandwich construction. Strip plank is worth considering but kind of heavy. For performance, plywood is great, it is light and strong but is not all that cheap, has to be sheathed with epoxy and rots really fast wherever there is a problem. Unless you want to build a Wharram which have a cult like following but don't have a saloon, they are all open bridgedeck designs.

[tcpbob]

It has been a decade or more since on this forum so maybe won't have all the bells and whistles in order but my response to the question is; 10 or 11 meters is enough room for 5 berths but don't know where you will put provisions and clothing and beer etc.. oh yeah, tools and spares. you may be expecting too much from the space but it would depend on the range you expect to cover.



i experimented with various materials when i built just to see. my favorite hands down is foam. good quality foam of correct density. it is easy to layup and reliable. ply can work ok. i think many people use ply because they have some experience with wood working so gets over the intimidation of the new materials. ply is good in any boat for vertical structure though. after market value favours foam i think or solid glass. if you desire performance foam is especially good. as far as taking the bottom, you either use keels with a metal shoe or something sacrificial or be very bloody careful. i take the bottom in my boat BareBones but carefully.


currently in Langkawi after doing everything from tasmania to philippines over last couple of years
cheers
bob

[double u]

“The one thing about plywood and the reason I like it is that it is a nice material to work with. That is a big factor when building a boat.“

Agree 100% - but not when the time of owning & cruising the boat comes...& don't let arguments like “epoxy over ply is like a fibreglass boat maintenancewise“ mislead you!

[Chotu]

Originally Posted by 44'cruisingcat

I agree with all that. Surprisingly Mike Waller's designs aren't well known.

On the face of it, you'd expect a ply cat to be much cheaper, marine ply being say $120 a sheet, vs DuFlex at around $500 a sheet.

But by the time you've glassed and epoxied the ply, the difference is a fair bit less. Then consider how much stronger and lighter the DuFlex is....

And the hull/deck material is only part of the cost. The cost to fair, paint, fit out, rig, fit engines etc is the same.

My boat probably would have been cheaper in ply, but in reality only by maybe 10 - 15%

Ease of working with a particular material aside, this is absolutely true.

"It's just as expensive and time consuming to build a crappy boat as it is to build a good one. Might as well build the best one you can. " - Chris White told me this. It was brilliant.

[Philipcataproa]

Jonannie, do not be misled by all the negative advice by people who have never owned a ply epoxy boat. It is the cheapest fastest way of building a boat. Provided you have used good marine ply the boat will outlive the plasitc boats. Wood does not fatigue like fiberglass. So a 20 year old marine plyepoxy boat is as stiff as a new one, but a fiberglass boat probably only has 50% of its original strength.
I have built and sailed two Marineply epoxy boats and I love them. The first a Didi26 mono hull and now a caraproa by Berndt Kohler. Berndt's designs is a bit revolutionary but works well and they are fast as well as safe. Dix designs are done well and some cannot be distinguished from fiberglass from the outside.

If you build well the boat will look professional.

Go for it.

[tcpbob]

so if ply costs about $150 AUD and epoxy about $30 per liter and the outside of the panel was laminated in 450 gr glass (1200X2400) so say about 1.5 liter resin (weight of glass slightly less that resin to laminate it) plus a liter or so to coat inside with sealer and resin.. so far less than $300 per panel.... cover with peel ply and ready to finish. not that you would do it that way but a way to compute costs.



i took advise from Bob Burgess, a really good aussie designer and builder, i laid out foam and joined panels with a little glue mix, laid out full length panels for the cabin and laminated the lot in one go. this is nothing new. i reported on the build of a polycraft boat in Maryborough Queensland some years ago and that is what they did. full length hull panels laid out on a table with good surface and did the lot. they glassed the other side as well but maybe with ply just put some tape on the joints to hold until mounted to structure.


laminating a full unit is the way to go and the shiny side discussed above is interesting. it is much easier to do full length panels however you do it. joining single panels creates more work and finishing i think.

this would work with any core material. nothing wrong with ply. i expressed my favourite and i have found cost does not necessarily translate into value. i have friends that built a Easy Sarah and did a nice job on fitout, outboard power and sold for $250K couple years ago. flat panels can take graceful lines if you let it. i have photos of all this stuff with me or on website called... oddly enough, buildacat.com

[valhalla360]

Originally Posted by Boatguy30

5 berths in the hulls of a 10 or 11 m Cat is going to be hard. I have seen a woods flicka with a forward single berth, but then you loose the watertight bulkhead. The Woods designs are probably the most economical plans price wise and excellent sailing boats.

5 berths or more is common on 10-11m cats.
- Our Gemini had 6 plus you could use the dinnet
- Our Catalac 10m had 5 plus you could use the dinnet.

Problem is how long are these 5 people staying onboard? Weekends...an occasional week, sure. Full time, this size range is going to be tough.

Also, I didn't see anyone ask but why are you building? You aren't thinking it will save you money are you?

[tcpbob]

"Also, I didn't see anyone ask but why are you building? You aren't thinking it will save you money are you?"



HAH! good question but there is an answer... i have seen people get really hurt by buying boats that looked great, built by professionals. Beauty was skin deep. Also, sometimes the boat that suits doesn't exist in the market, keeping in mind what a personal thing a boat is. Ply is fine, a little heavy perhaps in general terms but every material is a trade off of some kind. Also building your own boat means you are not held hostage in event of a repair. You know what to do and carry equipment and materials to fix it. Maybe why a 12 meter boat is just barely big enough for me.

[valhalla360]

Originally Posted by tcpbob

HAH! good question but there is an answer... i have seen people get really hurt by buying boats that looked great, built by professionals. Beauty was skin deep. Also, sometimes the boat that suits doesn't exist in the market, keeping in mind what a personal thing a boat is. Ply is fine, a little heavy perhaps in general terms but every material is a trade off of some kind. Also building your own boat means you are not held hostage in event of a repair. You know what to do and carry equipment and materials to fix it. Maybe why a 12 meter boat is just barely big enough for me.

What's your cruising experience?
What is your boat building experience?

Most importantly, what is the cruising plan with 5 people look like?

I've only built a couple of small dinghies but I have looked into larger boat building and I know a couple guys who built large cruising boats.

What I've come away with, building is great if you are in it, to enjoy the building process. If you want to get out cruising, buy a boat. If you aren't into high performance, there are older cats out there that meet your needs and you can always refurbish if you like projects...you will likely come out way ahead and have something with some resale value if you decide cruising isn't for you.