Hi Andy,

I am just embarking on my second Jr conversion, this time on a 24 foot 2 ton Cornish Crabber Mk1. As I am considering a tabernacle for this one, ( she is to be at least a potential trailer sailer) I am interested to read about your project and to see the various comments here.

 I would go for a strong setup over trying to save a few kgs if you can. With my sawyer's hat on, I urge you to use the best timber you can find. In my book, that means as slow grown as possible, and that any knots are small relative to the cross-sectional area of the piece. If the knots are significant enough, to warrant cutting them out and filling the void with something that is going to be much less flexible than the timber itself, then I would search for another piece. That's all very well for me to say sitting in Big Tree Country in Scotland!

Best of luck,

Pol

I am also working on a tabernacle for my Hartley TS16. Yesterday I did a dry fit and had a go at raising the mast. This proved to be a very simple and stress free process. My previous setup was an alloy tube through the foredeck. Raising the mast involved standing the mast up vertically on the foredeck, lifting it up and lowering it into the tube. An extremely precarious process, and most definitely not recommended. My tabernacle side cheeks are 90mm x 20mm and not strong enough. The mast has a bury of 600mm and is an alloy tube 6.5m x 80mm x 3mm.

I have two ideas to beef it up. Option 1 is a 40mm x 40mm stiffener running from below deck to just under the pivot bolt on both sides. My preferred option as I have the wood. Option two is alloy channel both sides with the flanges facing out.

Hi Andy,

My S2 6.7 is close-ish to the size of your Hurley 22.

I must say I am a little envious of the 2300 lbs ballast that you have in your 4000 lbs boat. With a 57.5% ballast to displacement ratio it should be almost impossible for your boat to do anything other than recover immediately after a knock-down.

Anyway, I built my tabernacle from 2" x 8" nominal (1.5" x 7.5" actual)  douglas fir construction lumber. Each board didn't seem all that heavy while I was building the tabernacle, but when it came time to lift it up to the deck it was clear that I was adding a lot of weight to the bow of my boat. My boat definitely floats lower at the bow than the designed lines. I would like to find a way to remove some weight, but I haven't quite figured out what to do.

In my opinion, if you can convince yourself that something smaller than 2" lumber is strong enough, you will be happier with the end result.

But, I am not sure exactly what to suggest. The only douglas fir I could find was 4" x 4" posts and rarely some 2" x 4" or 2" x 8" boards.

There is 1" dimensional pine (not douglas fir) available. If I was going to try this again I would take a good look at the modulus of rupture for standard construction lumber before using the 1" stock. I would then remove any knots, fill the voids with glass and epoxy, and then use that to build a much lighter tabernacle.

If you decide strength is everything, then go for the 2" x 8" douglas fir tabernacle. On my boat I have no doubt that the aluminum mast would bend and buckle before the tabernacle gives out. 

Scott.

Hi, I'm currently making a tabernacle for a 8m mast, stepped through to the keel, with 108cm below the deck (which is reinforced), and 100cm above. The mast hinges at the top via a collar, and it will have side braces that will also hold the turning blocks.

Currently, I'm using two 2x8 planks as the side plates, that taper down once they pass through the hull, using non treated construction lumber. I've used this lumber as it's proved impossible to get the ideal wood (as used by Annie Hill on her tabernacle), so have had to beef it up. But my question is, would I be better to use one or two layers of 25mm plywood for the side posts, and set a piece of lumber once they pass through the deck to handle the compression? Would the plywood handle the dynamics, stress and strain of a tabernacle better than a solid piece of timber?

Thanks

Andy