fastest home build method

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Origami "frameless" boatbuilding of various sorts can be fast.




Or if that design is too provincial, there are others ...

http://www.duckworksmagazine.com/04/s/designs/muller/yago/

 

Ian's prices seem reasonable to me. I assume the steel price is just the metal work, not the filler/epoxy/paint inside and out, nor the foam lining to stop condensation (not needed on a foam sandwich boat of course)

RW

 

Could this technique be used for forming catamaran hulls, or are they too thin ? I guess the bending forces would be much greater , requiring a block and tackle or hydraulic ram to bend the plates into shape ...?

 

I agree, especially when you consider its a custom built boat.

 

The method that Richard is suggesting is certainly interesting, so thank you for the picture and description. I can see that for a 'solid' grp hull this method might be a bit quicker to produce a hull shell than building a sheathed ply hull. The method requires you to make a female mould then use that to layup a hull(s). That mould has to be made to the same geometrical accuracy as is required for the resulting hull, so I would have thought that to the stage of having the mould ready for use it is about the same work as building a plywood hull up to the point of starting the external sheathing and fairing. But then you have to actually lay up the hull, you might find a contractor to that for you, with or without the use of a chopper gun. You do save having to do the sheathing on the ply hull, although that is not such a big job, and you do save much of the fairing and painting on the ply hull, although if the photograph shows the mould ready for use there will still be quite a lot of filling and fairing needed along the chines and panel joins after the hull shell has been popped out. So, overall I can believe that you could build a 'solid' grp hull shell that way with a bit less work than you could build a sheathed ply hull shell. For a foam sandwich hull I wonder whether you would envisage vaccuum bagging the foam and inner skin into the MDF mould or would it be by resin infusion? From my limited experience with relatively small projects, I have found both those methods quite time consuming to set up and they do require quite a lot of non-reuseable consumables, also a beginner can waste a lot of time and expensive material if they make mistakes with those methods. Even so, I would much prefer a foam sandwich hull shell to either a sheathed ply hull or a 'solid' grp hull, so regardless of the issue of build time, I think that would be my preference.

I was wondering what is the black filler along the joints between the melamine faced mdf panels - something like Duratek perhaps? Is more work going to be done on those joints before laying up the hull, or is it the intention to mould the hull rough along these joints then fair it later?.

 

Sorry, I should have said the mould photo was taken about 10 days ago before sanding and some more filling. The bow sections weren't fitted then. Yes the black is Durabuild highbuild paint, commonly used for plug building. I didn't see the mould after polishing but I assume it was all nice and shiny.

The owner requested infusion and s that is what the builder is doing, if it were me I'd just use conventional female mould foam sandwich as I have done for 30 years without problems

there is a huge saving in time with a gelcoat finish as opposed to a painted one. even with a smooth hull you still have to add five coats instead of one

Richard Woods

 

I did a jonboat mold this way, using this c̶h̶e̶a̶p̶ thrifty white tileboard from Home Depot.
http://www.homedepot.com/p/EUCATILE...d-Thrifty-White-Tile-Board-HDDPTW48/205995949
I made frames every two feet, lined the sides and bottom with 1 x 2s every foot or so and liquid nails glued the tile board to that. Filleted all the corners with Bondo and covered the butt joints with cellophane tape. A few coats of wax and some pva and the boat came out of the mold perfectly with no sticking at all.

 

If cost is not a parameter and assume that a home builder is proficient in fibreglass, woodworking, steel and aluminum welding, I would go with an aluminum hull

For maximum speed, again with cost not a part of the equation, I would choose a design from an aluminum boat designer, pay for his CAD cutting file, have a metal processing shop plasma cut all the components and then take them home for welding.

The advantage of aluminum is that you can cut all the components with most tools that you can cut plywood but the speed advantage of aluminum is joining up the plate.

For the most part, you will not need any type of backing to make up a welded joint, as you would for ply.

With ply you need to spend some time for painting etc which you could omit for aluminum,
As other have said though, the type and size of boat can make a difference

 

Welding aluminum can be problem some , esp for a beginner.

And there are equipment costs to consider

For decades aircraft and ships were riveted.

Perhaps not as light as welded , but most folks own a hammer and a rivet set and backing block are mighty cheap.

And probably lots cheaper to repair.

With bigger bucks the rivet areas could be sealed with modern metal glue , and the rivets would only be for assembly and backup.

 

15 meter catamaran, Stratos

This boat was built without molds in 1972 by four young men. Sandwich panels with only the outer laminate was made on a flat sheet and then placed in an outer template. Then the inner laminate was added. Only the joints needed to be filled and sanded to perfect finish.

In the same way I have built several prototypes that later been molded to production molds.

js

 

Not disputing any of the above, but the OP asked for opinions of what is the fastest way to build a hull.

 

I asked here on the forum about learning to weld alloy by experimentstion at home. The experts told me the first boat would go to the dump, the second would sink, the third would crack up in rough weather.....and the 4th would probably be OK. Lol.

My son was thinking of making alloy motorcycles frames; the course was 18 months five days a week full time....

 

I think everyone needs to consider the Derek kelsall method, which is essentially the steel orgimi method with foam and glass.
http://www.kelsall.com/

For a cat build, laying out flat panels on a mirror surface to create the hull, and then bending into shape, kills the female mould process.

Haryyproa builds use some of this technique as well.

It does away with the painfull fairing, painting and finishing of large plywood hulls.

R Woods comment about blasting, painting and insulating steel hulls is very pertinent.

 

Aluminum without paint and fresh water is one thing, aluminum, even with paint, and salt water is another animal altogether.

 

Aluminum can sit in salt water without any paint protection.
With the exception of an antifouling paint. There are hundreds if not thousands in the pacific northwest without any paint and they last just fine.