Catamaran plans, who have I forgotten ?

Regarding build time, it seems to me that aluminum would be the quickest to build. That is assuming one had plans with CNC files ready to go. Is this true? I like Richard Woods power catamaran designs, too bad aluminum plans are not available.

 

I would be working on it full time. I can't work anymore and there is no public transport here. I'm stuck at home only leaving for medical appointments shopping and I often spend the weekend at Elizabeth's place. 40 hrs/week is reasonable. The big problem is weather so I'd have to work around that. And discipline. Staying motivated and focused. I have very well equipped metal and wood work shops.

 

gussis3 there is a guy building the tristar 27'9" that posted a question on the forms awhile back , find his post and contact him on build time and cost .

 

It will take you 6000 hours, plus lost time to build the Waller 880 in composite; say 4-5 years, or longer, imo. Go quicker in strip..lot less epoxy and glasswork.

sorry; my other post got lost

 

I've linked this blog before, it's a 9x6m open bridgedeck cat with 1.4m wide hulls, stripped in WRC, unfortunately not completed (or the blog was not updated anymore). 24 January the raw wood is delivered in an empty shed, 22 May the first hull is ready for outside painting (no inside glass). Actual stripping begins 5 April, exterior is fiberglassed on the 21st. I doubt he worked full time.
The rest of the posts don't reflect the real time anymore, but they are worth viewing anyway.
Construction strip planking du Mahi-Mahi 2, cata open de 9×6m, modèle : One Off: Jour 1, Livraison du Red Cedar (tas de bois) http://one-off-design.blogspot.com/2016/01/jour-1-livraison-du-red-cedar-tas-de.html

For a wet glued build you can budget about one hour per full lenght strip. To this you aid fairing the wood (skill dependent, but let's say 1-2h/sqm), glassing (one day per hull side), fairing the glass (again skill dependent) and painting.

Building the raw shell isn't that much of a problem, going from there to a completed boat is.

 

What experience do you have with Aluminiun ? First in this size it'd be too heavy unless it was very carefully engineered. Second aluminium has a different structure to steel for example and it will inevitably stress crack over time, that's assuming it doesn't fizz away to nothing due to galvanic corrosion in sea water.

It can make sense in bigger boats but in this size multihull it'd be a serious problem.

I wish it weren't true. I would weld up an aluminium or steel hull in no time. The result would be terrible...

 

There is a youtube vid of him sailing in 2020. There is a link to his videos in the blog, then go to channel. It obviously depends a lot on how well you stick to it, how many hours each week, travelling, life changes etc.

Thank you all for the comments. I apologise if I miss acknowledging any. I am reading and following links etc.

 

Hi. Build hours are a problem. I have seen people build the exact same design and 1 guy took 3000 hours, the next guy over 5000 hours and another close to 7000 hours. The difference the first guy had built several boats before and knew how to use foam glass and process built everything in the correct order. EG 2 sets of float frames at once, all the main hull bulkheads, all the cross arms at the same time. He had all the components ready to "assemble" the boat. But far more importantly he knew exactly what gear was going where and had put in hard spots, bolt holes, electric lines, plumbing holes etc as he built. He was organized, had all the tools required and a shed next to his home plus the scraps of stuff need at a moments notice.

The slower builders did things one step after another EG complete one float then start the next, oh I forgot to put in a drain hole in the bottom of a bulkhead, the cross arm I built doesn't quite fit the float bulkhead. I should have put a hard point there for the out board etc. Where do I fit a water tank? The end result is a slower disorganized build which then can be compounded by building outside in a location 20 miles from your tool supply with a minimum of pre purchased materials. You are waiting for supplies, you occasional have to rework things due to different products not being available etc.

And the final killer, you redesign things as you go. Even small changes (EG raise the roof line slightly) have down stream effects like track and winch positions need to be changed. You want a longer bunk which either shifts a major bulkhead or causes an internal redesign. All this adds hours.

But the biggest choice you have to make is perfection versus adequate. I know one builder who spent over 6000 hours building a plywood Devlin 19 ft Winter Wren. Why? EG because the tape joints joining chines together were not smooth and had to be sanded out and redone, the vanish finish on the deck edging had to have a french polish finish etc. this was to be a statement of his workmanship. Other builders have done the same design in a 1000 hours with a sensible finish. Your choice but boating in the real world is about knocking against wharfs, occasional running aground and breaking things.

If your building to resell OK put some effort in to get a good finish, but if you are building to use and cruise then keep it simple and do a major fix up prior to selling. Very smooth pretty boats with expensive paint jobs don't remain that way in the real world unless you pay some else to fix them or spend a lot of time maintaining them.

 

The only thing that makes me nervous about aluminum is galvanic corrosion from stray current at a poorly maintained marina. From what I have read it can happen fast in this situation.

I have experience with welding and fabricating aluminum. If aluminum is quicker to build, I don't agree that aluminum should be so quickly ruled out, as its been a proven material in boat design for many years.

 

When I built the Skoota, I stopped for two weeks because my first panels were resin starved until I determined to add bleeder release film.

Quality issues take time. More for first time building in a certain style.

I built softwood roof beams. That took a good week alone. Had to rip them to size, build a table I could screw into, make separation blocks, and then I could only get 4 or so beams on at a time, so laminating was 3 days. These are not the kind of thing you purchase.

Want solar? Add time to get the panels, time to fab mounts, I'd say I got 5-6 days into the solar system; maybe more. I have victron control systems; cerbo, etc.

Shore power? The shore power system cost me about $1000, plus $1500 for the inverter, and about a week for buying, cutting into the boat and wiring. Then I missed a wire and spent another hour just before survey running a ground from the DC to AC system.

The marine head. Easily I have a week into buying, placing, shimming, plumbing it and b/w tank.

A lot of stuff may not be specified; that also adds a lot of time.

My boat is very complex. The better the plan set; the faster you can build; the Skoota32DM was a brand new planset without lotsa details on systems.

people can laugh about solar taking a week or the marine head, but these are realistic...just sourcing cable glands takes time..

 

fallguy is making a very good point and I think what we are all trying to say. But if you take a plan from most of the major designers and build it as per the design then the build time should be in reason to man hours stated on the plans. My Horstman plans are very detailed, I have spent most of my life in heavy construction dealing with man hours per sqft, there is no reason a tristar 31 can't be built as per plans in 1200 hours or less either in ply or hand laid foam / glass as stated by Ed . Deviate or add to those plans, don't have materials or have clear method and means all ready and settled before you start and 1200 becomes " when ever you finish '. You need to go over the plans until you can see the build take place and completed in your mind , you have to always know your next step and be prepared with material, tools, and skills before you get there. You should never have to stop and think. And a work boat finish is the way to go in my view.

 

Being able to weld aluminium is irrelevant. When I was young TIGs were unheard of. We welded aluminium with oxy. I used to practice by cutting a drink can in half and welding it back together then fill it with water and see if it leaked. I can make metal and plastic do anything I want it to. Most of my working life was designing and building experimental apparatus. I used to routinely do stuff other tradespeople thought impossible, techos who themselves could do miracles. It's irrelevant.

The problem with aluminium skins is they need to be rugged enough to not tear but light enough to not overload the boat. A foam glass skin in this size boat is less than 3kg per sq meter and it required no supporting structure because it's terribly stiff. An aluminium skin with the necessary supporting frame is heavier. Across the hull it adds so much weight you have no payload left.

Fallguy: I tried to emphasis previously I was not asking about fitout etc. Just the hull specifically. I've done all that other stuff. I know how to do it and how long it takes. I know how to buy and fit a head and holding tank, and good lord knows I know how to plumb and wire, and rerig, and.....

The bit I've not done is build a hull from scratch. I know how to repair one, but I've had such conflicting comments on actually building the thing.

If I built the Waller 880 the only change would be the foam for ply and maybe the cedar for foam. I might swap a couple of the hanging lockers for bench or drawers. I don't quite understand why you need so much hanging space. I had thought I'd mirror it but I think I wouldn't do that either. So just a couple of minor changes.

The Woods boat option, that's more work. I'd try to substitute one of the bunks for a dinette, and galley down. The boat is drawn with galley in the cuddy. I'd omit the footwell, only a mattress in the cuddy. And for Saturn I'd want to scale it up in XYZ, which is trivial, but LAR keels and maybe rudder. Bigger changes.

I don't want a luxury cruiser. I want essentially a floating camp site. The head is important, and I like to be clean so fresh water and a shower of some sort. I can cook in the cockpit if necessary. The bed is critical.

I've been trying to see what vision forward is like on the Waller. I'm not sure it's very good. I THINK the cabin is about 3' higher than the cockpit seat. I guess you just have to helm standing up when close to others.

 

Building hulls outside is going to be hard. You want to cutdown sun exposure or rain exposure times. Can't have rain on a female shape. A male mould in foam has issues because the foam is not strong enough to demould without bulkheads. I've seen a Woods build kept on the frames and deframed as BH were placed on edge.

Building a wood strip hull; you can do upside down and tarp. See progress quickly, plank in multiple directions on both sides. One of the most fun things I ever built was a strip canoe. The laminate schedule is your friend; easy, less epoxy, no vac needed. A few stiffeners and you can flop it over. It'll get wet easy this way n then you cannot laminate, so that will be hard to do unless you time it well during dry season.

I'll try to not badger you more, but building outside is a large hurdle as well. You can't have the female shape out for long is the main thing, so if you will build; you need to plan for the environment challenges as well, unless I grossly misunderstood.

 

First and foremost I don't resent your comments, I appreciate them. I'm often trying to warn people off what I see as bad decisions. No one ever listens to me either

Mr Woods has written to me. It looks like Scorpio is back on the table. I think for me it's a better solution.

The only part of Scorpio that needs to be molded is the hull bottoms to the knuckle. The rest can be flat panel. My plan is to do all this with infusion so humidity and rain become somewhat irrelevant. Maybe. Brisbane temps are mild and as I live on the side of a mountain we never get freezing overnight temps even in the dead of winter. The lowest I've seen is probably 10C (50F?). The hottest day in Summer is 39C (109F). That's a once in a decade temperature. Sydney for example routinely gets both colder and much hotter than Brisbane. What I missed before moving here is the humidity which makes breathing a misery in summer. Humidity is an issue for MDF frames. At least it's consistently high

Until the last few years we got almost no rain in winter. Being subtropical we don't get 4 seasons, only 2. April to September is mild and traditionally dry, while October to March is hotter humid and wet. The last few years it's been a bit rainy in winter. Kinda weird. I used to be pretty good at meteorology. My forecasts were more reliable than the bureau, although that's a low bar. Now like everything it's more of a challenge.

Building under a tent will have to be managed. Rain isn't an issue, but temperature swings and humidity potentially is...

 

You just can't close a wood hull under high humidity. The emc should be below 12% or you risk the wood rotting inside under sheathing both sides.

A tent is going to be helpful. I used one here that was 30x40. It was up for two years or, well, about 23 months. It was a Chinese hoop tent. Horrible under snow.

I was over pavement which was nice. The hulls were completed and cabin in climate controlled; then the whole boat was put together and the tent erected over. A crane had to lift my cabin as boat is demountable.