Curved surface on plug?

Having worked with both -

Pine is definitely cheaper, but is much more knot prone so hard to get much length. That being said I created a 37' female mold with the rounded part constructed soley out of doug fir 2x6's that I cut into 1/4" strips with a table saw. It worked, but for anything requiring significant curvature, I definitely prefer cedar strip. Much, much more flexible and easier to work with.

As an example, if you take an 8' strip and try twisting it (like a rope), you can twist the cedar at least 90 degrees without too much trouble. If you twist pine that far it will break. Easier to twist = easier for complex curvature.

 

Lots of types of pine, for boat building you should try and find long leaf. rick

 

Absolutely correct. very handy trick.

For the fibreglass sheet, I found that 16oz (200 gsm) cloth, plus one layer of chopped strand , between two melamine (waxed) boards makes a tough but really flexible sheet. The cloth alone seems to be too floppy.

Also, For really tight bends on thin (4mm ) strips of wood, epoxying on a 16oz cloth on the outside of the bend, makes the wood a really, really flexible and strong batten that can be twisted and warped amazingly.

 

I've got a female plug for a 10' skiff and have the same questions. Could you use 2 layers of 8 oz fiberglass cloth + 1/4 plywood + 2 layers of 8 oz cloth + woven roving be strong enough with out additional structural supports? If not what would be a better way?

 

are you asking about what to build the boat out of ?

Usually you dont use plywood when you build from a plug.

 

Thank you for replying about the plywood. Yes, I am asking what the minimal layers of fiberglass and core that are required to build the hull without stingers. There will be two bulkheads, one where the forward deck ends and one where the seat/aft deck ends. I was hoping not to reinforce it any more than that. Would 3/8" Core Cell in lieu of plywood throughout the hull, sides and decks be adequate with the same lamination mentioned earlier? The goal is to keep it light yet strong. Can the Core Cell be used without vacuum bagging or is that not a good idea?

 

So, assuming you are not planning to use plywood in the plug, you are planning to use a foam like Corecell in the plug ?

What you are asking is a not a straightforward question, and unless you can afford to find the optimal hull building method by trial and error, you need to engage an experienced and qualified professional to tell you. ( which I am not )

With the limited (nonexistant) info you have provided on the hull shape, crew load requirement, rigging loads and a host of other info, the only thing I can offer is :-

1) Applying Corecell or other foam into a female mould can create real problems with bonding to the outside skin without vaccum bagging.

2) Asking someone else who has done it is the cheapest way to find out - but there are a big variety of 'skiff' hulls, and you havnt provided any info about yours.