weight comparison, Carvel v cedar strip

PS, tried to buy Elements of Boat Strength (I have his book on props which is excellent) but Kindle no requires 2 step verification via mobile phone so will have to wait until I get home as I don't have mobile access here.

 

In order to have a speedy build, I advise buying a plastic nailgun (Raptor or similar), a powered faring board (Flexisander or similar), using unplaned square stock for stripping, and laminating the frames and floors directly into the finished hull.

 

Roland, is your Checkstone effectively a slightly larger version of the Checkstone 28?
Here is a 28 for sale -
1976 Bickford Checkstone Custom 28 Sloop for sale. View price, photos and Buy 1976 Bickford Checkstone Custom 28 Sloop #178962 https://dailyboats.com/boat/178962-buy-bickford-checkstone-custom-28-sloop-for-sale

You mentioned that your new boat will be deeper, and about 4' longer on deck (while keeping the same beam?) - so she will now be your Checkstone 36?
I see you also mentioned a mizzen - mizzens were popular when she was built originally, as they did not have roller reefing for headsails and it was a good way of splitting up the sail area into more manageable sizes. But I guess that your mizzen is useful for helping to balance her nicely while underway, hence why you will be fitting a mizzen on the new boat as well?

 

The 32 was developed from the 28 for a specific customer but is significantly different. She has a higher bow with more flair and a deeper keel also a lower coachroof and center cockpit. She was built to the JOC rule and I believe copeated in both the Santa and Fastnet races. Altogether much more of a sea boat. When I refitted her for cruising I also added a bowsprit to set a large lightweight goaster which worked very well upwind. Plus adding a square sail spar that sets a triangular topsail above, all controlled from the deck. The square sail is fabulous, will work as high as 100 deg off the wind gives a significantly larger projected area than a spinaker but drop the topsail and reef the square and she will happily handle 25kn over the deck. The foot is well up so out of the spray and high enough not to get blanketed in the troughs. It is so stable I was happy to leave it up at night on autopilot across the Atlantic.
Never liked roller furlers, I have seen to many go wrong and you can't change down to a smaller heavier and flatter sail when the wind picks up without first unfurling the sail entirely.
I want to go for a ketch rig this time and 36ft is big enough for it to work well. It is partly because it means I can reuse the mast, rig and sails from Voya one but also I find the flexibility really useful on a ketch. If you get a sudden squall realease a couple of cleat to drop the main and jib and you are left with saysail and mizzen, good for 40kn and perfect for heaving to. You can also set a riding sail at anchor which often keeps her into wind and waves and damps a lot of roll.
On beam Ihavescaled the plans so that added about 6" of beam and keeps the ratios the same. I anticipate adding more weight to thekeel as well but need to finalize the calc' before sorting that one.

 

Epoxy resin will absorb approximately 3% moisture after a prolonged submersion. That is much lower than kiln dried wood will be over 6%, so there is no issue about moisture migrating from the epoxy to the wood. Millions of applications of wood waterproofed with epoxy show that there is no deterioration, unless there has been some break in the epoxy coating.

 

I am excited about your build, but you have posted some things which are simply invalid. I'm surprised others have not commented..oops, I see Gonzo has

You really ought to find out how the commercial outfit manage bilges; a seam crack would allow water to get deep into the hull. Their pictures show the cuddy as painted.

These hulls also appear to be diagonally laid, so we may be missing some aspect of their product.

 

I absolutely agree with the facts here. If the wood core is at 6% and the epoxy layer is at 3% with no breaks in the encapsulation that would be stable and the wood would not absorb any more moisture. So in theory encapsulation is fine and many hulls have been successfully built this way in professional yards although with notable exceptions, remember Macmillan yachts in the UK?
My primary concern is that I will be using Air dried wood probably at around 12-14% and working in an open shed for the build. I am building on
the N/W coast in a remote area and kiln dried cedar would have to be brought in and shipped more than 1500km making it prohibitively expensive. So first point is that I don't think it would be practical to get the hull dry enough for encapsulation to work. The second point is that It is extreamly difficult to ensure that there are no breaches in the build or the life of the boat so maintaining the integrity of the encapsulation would worry me. I am looking at this as more like traditional double diagonal build but using epoxy bonding between the layers instead of canvas/bitumen or other bond. That system has been proved over time but epoxy bonding would make it stronger. The plan is to use a first layer of 1/2" strips 2-4" wide (depending on the local curves). That will be followed by 2 diagonal layers of 1/4" boards and a final layer of horizontal 3x1/4" boards giving giving 1 1/4" total. I may move up to slightly thicker boards below the waterline if the wood is flexible enough. The finish coat will be epoxy with a woven roving finished using peel ply and varnished above the waterline. Decks cockpit and cabin tops will be ply with a double coat of epoxy and roving then painted. Cabin sides & brightwork will be solid or laminated timber and varnished. I appreciate this may be a little unconventional but do have a reason to think it would not work? The only issue I can think of is if moisture content of the wood changes significantly between layer or areas it could create internal stresses. In thraditional double diagonal construction these were absorbed by the canvas layers. If this is likely to be an issue I could look at flexible epoxy. I have successfully built cold moulded canoes bonded with resoursonal glue (before epoxy was available but nothing on this scale so thinking this through and trying to find the potential problems!

 

Exterior builds are definitely a valid concern. Entraping ambient moisture is very bad.

 

The method you are choosing requires a reasonable controlled environment. An open shed in the NW coast is about as bad as it can get.

 

Back home now and it has gone from plus 30c in panama to -20c in Canada, bit of a climate shock!
Looking at hull forms and using Delftship to do some modelling. But I can't seem to get any of the calculations to work and the manual is f*** Useless! Any suggestions? I have got as far as a complete hull model, both sides with transom attached but no deck. The program is reading numbers like beam and length and even wetted area but nothing on displacement, drag and balance which is what I really wanted. First time trying 3D Cad but lots of experience with 2D and previously done the displacement calcs' by hand but I was hoping for something quicker!!
I am also wondering if there is a vapour permeable version of epoxy that would breath like the traditional 'tar and oilcloth' that was used for double diagonal construction before we had epoxy. Anyone heard of such a thing?

 

The Falmouth Quay Punt 'Curlew' was originally built in 1905, and many years later she had 3 layers of New Zealand kauri cold-moulded over her originally carvel hull planking.
Falmouth Quay punt “Curlew” – BC09 | National Maritime Museum Cornwall https://nmmc.co.uk/object/boats/falmouth-quay-punt-curlew/

And she subsequently made many notable voyages, including to South Georgia, the Falklands and Antarctica.

 

Got some modelling done on Delftship to look at what happens with increased size and some other changes I want to make. Delftship seems to give some good numbers for balance and trim but weight and displacement seem out. Can anyone point me at a good explanation of what the numbers mean? When I put in a hull thickness of 1.25" and a hull density of 25lb/sqft it reckons the hull would weigh 48.71 ton, seems to think I am using 1/12" steel not wood? What am I doing wrong. Also with an appendage coefficient of 1 does this mean the calculated weight assumes machinery, spars and fitting weigh the same as the hull and is that included in the calculated weight. Sorry if these are real basic questions but I am new to 3D modelling and really struggling with the manual.
PS, yes I know Curlews history but want to explore composite construction before deciding

 

You may want to start a new thread with your Freeship questions.

 

If I remember correctly there is a dialog tab in the layers menu where you can set the actual weight of the used materials.