Wooden Mast Detective Work - with questions.

[lesweeks]

The yawl I'm restoring has a broken mast. The bit I have seems pretty sound - a shake or two but nothing too sinister. It appears to have broken somewhere below the hounds as there's no evidence of them on the broken end. Problem is that I have no record of how long/high it should be. I have just one photo of the boat afloat, which is pretty well side on, and from this I have calculated (well measured actually) that the height above the deck is exactly the same as the length along the deck (25'). Does this sound about right or is it just a coincidence? If it is right then I'm missing 8'6" in old money.

Secondly, the bit I have (16'6" ish) is parallel at about 4" - 4 1/4" diameter along the full length. If/when I splice the missing length back on should it remain parallel or should it taper towards the top? If so what sort of taper?

Any advice much appreciated.

 

[Peterduck]

With a yawl rig, it sounds like a cruising boat, so it will be modestly rigged. For the mainmast, which is the one I assume you're contemplating, a length equal to the length on deck sounds about right. Do you have any sails which you can measure? You could do a lot worse than compare your boat with an Albert Strange yawl of the same size, via the book about him and his designs. A parallel-sided mast suggests a gaff rig. Yes, the mast should taper above the hounds, and I would suggest a cap diameter of about 2.5" . This will be determined by the peak halyard sheave, particularly its width. Choose a diameter which will leave at least a slot-width of timber each side of the slot. As you have to graft a top onto the lower part of the mast (assuming a pole mast, and not a fidded topmast) you have the chance to build a hollow top section, relieving a little weight aloft.
Peter.

 

[lesweeks]

You're very perceptive! Yup, a 25' Gaff rigged, long keel, yawl with a pole, no topmast.
Thanks for the comments, it's helped me sort things out in my head. I hadn't considered the hollow option and it may not be possible with the timber that I've got available. Also I'm not sure what the weight saving would be over such a short length.
From what I can tell from information left with the boat when I bought it, there were no sheaves in the mast; blocks were attached to (what I assume were) eye bolts bolted through the mast. Sadly, the photo that I have is not good enough to make out such fine detail. I peer carefully at every Old Gaffer that I see to try and spot such things!