View Full Version : Tapering an aluminum profile
12-04-2000, 10:50 AM
Hello, I'm building a 14ft sailng skiff which will carry about 160 sqft of sail and will have a double wire. I'm figuring on how to make a mast that will cope eith the kind of loads this will result in. The thing that is on my mind an aluminum mast made from som sort of extruded aluminum, but I want it tapered the top 5ft. Is it possible to do this with normal tools as vises and pipewrenches??
If there are any way to do this please reply and soothe my worrying soul
12-04-2000, 12:14 PM
You can cut and shape aluminum with a circular saw, power planer, disc sander and a big mother of a pipe wrench if you want. Just wear eye protection.
12-04-2000, 12:21 PM
If you are willing to part with the bucks, a Procter tapered spar should fit the bill nicely. A straight spar can be tapered by cutting "V" darts on both sides and welding back together. This is not easy to do and there is a risk of taking the temper out of the aluminum and changing the bending characteristics in unpredictable ways.
The other side of this is that spars tapered in this way have not proven superior to straight ones in one design classes where they are allowed. Weight and windage saved in this way is pretty insignificant in a 160 sq ft rig. By double wire, I am assuming you mean double trapeze rig.
12-04-2000, 12:27 PM
Sounds like a lotta work. Why not make a bird's mouth hollow wooden spar finastkind?
12-04-2000, 02:51 PM
have not left a wooden spar out in any way, just ahve a feeling that the kind of loads I will apply would take a quite heavy wooden spar, and weight is quite important ( the plan is that the boat will weigh less than 200lb.
Yes I mean double trapeeze rig. I'm owndering about loosing the temper, would that be du to the welding or due to the bending of hte material? I think the taper is most to get the proper bend of the mast for the sails. Would be more than happy to have enough £$ to part with but unfortunately have not.
I've heard of veneer masts for iceboats, odes anyone have an adress to an internet resource about this??.
12-04-2000, 03:27 PM
Here's an iceboat site.
International DN Ice Yacht Racing Association (http://www.paw.com/sail/ice/)
and here are the Articles to build a mast:
But you do realize that the mast they use is a rotating mast
You'll need to rig it as such.
You could also hit a local Hobbie Cat dealer and get a complete rig for a boat that's hull has delaminated.
For a skiff your probably better off with a simpler stepped rig.
[This message has been edited by BrianCunningham (edited 12-04-2000).]
12-04-2000, 03:41 PM
Hollow wpood may easily be lighter.
At the ME boat builders show I had a chance to pick up a bird's mouth spar that was considerably longer and stronger than the aluminum sunfish mast I use as my dory's mast. It was also lighter. I could hold it out horzontal with one hand at the heel.
12-04-2000, 09:27 PM
The aluminum mast is probably 6061 with a T6 temper and the heat of welding would be the culprit for distorting the temper. While you are considering bending characteristics, think about the stiffness of a cylinder versus a cone of equal base dimensions. If you want to make the top section more flexible, I don't know if tapering is going accomplish that. It may even be stiffer. Anybody done this before?
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