Got my DS12 plans, thanks Chris and Eric! I have two more questions.
First, are the hulls sheathed in fiberglass?
Second, what mast is recommended? is there a particular cross section or dimension?

If you use 3mm ply I recommend a thin layer of glass. If 4mm like Gato used don't bother. Keep reading the drawings the glass weight etc is mentioned there. With respect to masts any extrusion designed for a two person dinghy will do or once you finish the hulls I'll send you the drawings for the carbon mast ad per gato's web site.

Thanks Chris.

While studying the plans , it appears that the chainplates for the shrouds and forestay/bridle are mounted externally on the hulls. Is this so?

yes. Its a simple boat and this is less likely to cause leaks.

all do not click on the links in jinhua1 post.. its a worm/malaware site

Scarecrow,

are you saying that an external chainplate with 3-4 through hull bolts are less likely to leak than a chainplate glued to the inside of the hull?
In the case of a chainplate glued to the hull inside, there is only one through-hull penetration. I though this would give better odds on leak prevention?

Rolf the chainplate is screwed not boltedbso there are no holes all the way into the boat. But even if that where not the case it is very difficult to get a flat metal plate (either Ali or stainless) to property seal as neither likes glues or sealants because of their surface oxide nature.

Understood

We have this F16 build going and we are just about to install the chainplates in two hulls. Building plans specify gluing in the chainplates, which I am fine with. Will use epoxy thickened with collodial around the fitting where it exits the ply deck. Then use marine sealant on top again. Not perfect but at least no open wood for water to seep into.

My first Tornado had the chainplates bolted on with bolts penetrating the hull skin + backing plate. The original ply backing plates had rotted when I got the boat so I replaced them. Quick and easy fix, but the best would have been to avoid the problem completely. Now I would have drilled the holes oversize. Filled with thickened epoxy and re-drilled the proper size.

Next boat will perhaps have carbon chainplates which is a different story.

my chainplates (taipan F16) are glued in and they are still there. I have complete trust in them.

Phil Brander came up with a working solution as indeed glues have trouble sticking to aluminium etc. What Phil does is dril many holes in the chainplate and set it into a layer of thickened epoxy (epoxy with filler) and laminate the chainplate in. The thickened epoxy filles the wholes in the plate and hardens out as pegs that keep the plate in place. The laminate around the plate keeps it in place (on these pegs). I think there were about 9 hole in the plate where it is laminated in.

Wouter