I'm looking ahead in the building process and in regards to the mast I'm considering making a birdsmouth instead of a solid mast. What I was wondering is that if you go birdsmouth do you have to step the mast or is there a way to keep the folding mast system that the plans call for?
Van my input on this is Yes. Make the stump solid up to the tabernacle and use the birdsmouth from there up. this is even better you have the weight down low and almost nuthing above. Good idea I see no problems with this. Bud
This is the ticket to better sailing performance and especially raising and lower the mast, which is considerably lighter. A Weekender mast with a 3.5" base and tapering to 2.5" at the head will weigh about 15 pounds with a 20% wall thickness, built from a relitivly light weight wood. If Douglas fir it will be around 18 pounds. Now a mast sized for the actual sail area of a Weekender only needs to be about 2.75" at the base and 1.75 at the head to be more then strong enough. A Douglas fir mast this size will be about 11 pounds and if white spruce or other light weight wood in the 8.5 to 9 pound range. Now that's a stick I wouldn't mind lifting and dropping into a hole on the deck.
In fact, if you want to get real technical. If you built a 3.5", tapering to 2.5" mast of Douglas fir, you wouldn't need shrouds to hold it up (unless deck stepped of course). This mast is stiff enough to tolerate force 5 winds with little worry. Small craft advisories are issued with force 5 winds and you'd be running for shore or have tucked in a reef by this point anyway. The smacks which the Friendship sloops descended from had rigs like this (free standing).
Thanks for the replies. So Paul, if I'm picking up what you're laying down, you're saying if I made the birdsmouth mast the full length in one piece and stepped it in the mastbox without the folding tabernacle gizmo, I could forego the shrouds and have a freestanding mast? If that's true I think it would be worth the inconvenience of not having a easy folding mast in trade for no shrouds to clutter up the operation. Has anyone else built a weekender with this setup?
I believe that you could use a junk rig on your boat. As I understand it. Their mast are un stayed. I read Annie Hills "Crusing on a Small Income" she is a very strong proponent of the Junk Rig.Â
Here is a link about Junk Rigs.
http://www.junkrigs.com/
Many different types of rigs can be freestanding, including the junk, though you don't want to get me started on the qualities of that particular rig, which I have a fairly poor opinion of.
With a free standing rig, as a gaff sloop, you'll still have a head stay of sorts with the jib's luff wire, when it's up.
Tabernacles have served well for many centuries. A more secure and stiffer mast can be had with shrouds and stays. On the other hand, they can be a bother if you hoist and douse the pole a lot, as trailer boat do.
I don't know of any one that has use a free standing stick, on a Weekender as a gaff sloop, though Ryerson has a lug sloop that is free standing.
Peter and Annie Hill built a Jay Benford sea going dory, fin keel and all. They put a divided junk rig on it and have ventured 10's of thousands of miles in "Badger" ever since. The book was an income source to fund their cruising life and really a good guide on how to manage a small boat as a cruising live aboard and as economically as you may wish.
A better junk rig guide would be "Practical Junk Rig" by the indomitable HG Hasler, though I personally still don't think much of the rig in general.
Would the 3.5-2.5" freestanding rig be substantial enough for the VAC? This with a sock-luffed sail with a hollow gaff pole?
Now, the freestanding pole needs some flex, which allows excess wind to be dumped from the sail. Would it be a good idea to build the birdsmouth, say 8 staves, from two kinds of wood, one stiffer, one more "springy"? I was thinking spruce and ash (4 staves each), glued either with goo or resorcinol.
I also have a roll (50') of 12" carbon fibre (biaxal) cloth. I was thinking of sheathing the rig with it. Good idea?
Bendy, hollow masts are fairly highly engineered things. Taking a "stab" at it wouldn't be a good idea. Amount of mast bend, stave dimensions, sectional modulus, elasticity modulus, average wall thickness for a given wood species, physical dimensions to match physical attributes desired, etc. all need to be considered. You can mix species, but generally it's not necessary.
Why? Well, there's no sense in using a free standing rig, unless you get something out of it. Other then setup time, light weight and windage aloft are the major reasons we use free standing masts.
Marcin, your carbon would be best used on the gaff. The 50' you have will not help the mast much, unless you think you could get a good resin/fiber ratio in multiple layers of carbon, all in one shot. Used on the gaff, you could have a slightly tapered pole used as mandrel, to wrap your carbon. Remove the mandrel and you're good to go.
To answer your question. I don't know, because I haven't run any numbers on Vacationer.
On my birdsmouth  mast I used an 18" octogonal shaped plug at the top, bottom and where I cut for the tabernacle.  There needs to be plenty of backup in those areas.