AD 14 question for Jacques, unstayed mast

[bondo]

Any details for an unstayed carbon fiber mast? I've ordered the small boat cf mast kit for building the boom. Thankyou for your help. Pics of the mast step and partner.
Mast partner as built, not yet installed. Thankyou.

[jacquesmm]

Let's summarize what we discussed yesterday.
After your phone call, I checked and can confirm some figures.

As usual, and this applies to everybody, if you want real figures and correct information, please post here.
If you call, I can rarely answer accurately. I prefer to take my time, look at the plans and give a better answer in writing.
(Bondo called to order, not to discuss his mast).

The best way to build a carbon fiber mast for the AD14 is to follow the plans. The plans give specifications and show minimal shrouds.
Note that those carbon fiber scantlings are based on quality lamination with Silver Tip resin, vacuum bagging and post cure.
If you build another way, you must increase the scantlings.

Bondo wants a free standing mast.
I don't see the advantage but it is possible.
In that case, I recommend to reinforce mast partner and mast step.
It was done.

I also recommend to increase the mast diameter.
Ideally the mast diameter should be 3" from the step to halfway up then taper to 2".
The 3" lamination requires one extra layer of C fiber.

With a 3" mast, you need a 3" + hole in the partner and that means a slightly wider partner to keep the same offset around the hole.
It also means that you will be close to the mast frame but that will work.

There is more.
At the partner and at the step, the mast must be reinforced to resist crushing. That means either many extra layers, let's say a final wall thickness of 1/4" all the way up to 8" above the gooseneck.
This is not specific to the unstayed mast, the standard one must also be reinforced there.
We show that in our mast building tutorial.
The result of that means an OD of 3.5". See above how to make the hole and partner larger.
It's getting real close to the mast frame and will limit the possible rake adjustments.
If you do not want or can't go that large, you must reinforce the mast from inside.
That means a wood or Al mandrel.
That mandrel must be tapered at the top to avoid a brutal discontinuity in strength. Wood tapered of Al pipe with slits.
At the mast step, the mast can be tapered down but reinforced outside or use the same mandrel.
Or start with a foam mandrel of a smaller diameter there and build up layers.

A last solution is what I wrote last year: keep the same diameter but add one layer of C fiber.
That will give a 2.5" ID mast but it must be built perfectly. If not, add 2 layers.
It is always safer and easier to get stiffness from the diameter.

Last, you need something to keep the mast onboard. An unstayed mast may "jump" around if not secured.
This can be a return of the halyard to deck or a separate line.

It is much easier to stay with the plans and have the simple shrouds we show.

[bondo]

I'm very disappointed Jacques. I don't understand your inconsistencey on the subject:
[quote][/qReport this postReply with quoteby jacquesmm » Fri Feb 27, 2009 9:02 am

Yes, the best application of amateur built carbon fiber spars is for small boats with unstayed rigs. Up to 16', free standing only.
That means many of our dinghies plus the AD14/16.uote]
I don't need the carbon fiber boom kit I ordered until I decide how best to proceed.

[sitandfish]

I'm very disappointed Jacques. I don't understand your inconsistencey on the subject:

[/qReport this postReply with quoteby jacquesmm » Fri Feb 27, 2009 9:02 am

Yes, the best application of amateur built carbon fiber spars is for small boats with unstayed rigs. Up to 16', free standing only.
That means many of our dinghies plus the AD14/16.uote]

bondo, are you planning on using a 16' (16' or shorter) mast?

[bondo]

I don't understand the question. Are you suggesting he meant a mast no longer than 16'? Why specifically mention the AD4? They were talking about the AD14 cf mast kit.

[sitandfish]

I don't understand the question. Are you suggesting he meant a mast no longer than 16'? Why specifically mention the AD4? They were talking about the AD14 cf mast kit.

I was just asking you a question? No suggestion about what Jacques meant. You don't have to answer.

[bondo]

I apologize sitandfish. I guess I mistook your question. I'm upset.

[das boot]

are you located in Washinton state if so you are close to me I have had my AD16 saling for 3 years if you want too take a look at it it should be back in the water by next week

[bondo]

Hey, nice to hear from you das boot. Yes, I'm in Seattle. There is another yellow AD in Vancouver, or is that yours? Been to your city many times. Awesome. Really beautiful place. Do you like the AD? You know I have a million questions. My 14 isn't going in the water until next year. I probably need the extra time to finish it anyway. I want to hear about your boat. I've only seen pictures of four different AD 16's and none of an AD 14.

[das boot]

yes that yellow boat is mine it came out just the way i wanted it to this will be year 4 for it with no problems i have been going to take it to seattle to sail with a frend of mine but crossing the border with a boat today is just too mutch of a pain so tim came up here you are welcom to come up and go sailing on das boot aneytime i am just getting it ready to put into the watter in the mext couple of weeks you can get me on the phone 604-649-3847 most of the time