Yes David. My first boat, 'Miss Molly', had a, by PJR standards, very much undersized grown mast. It had large shakes in it; it flexed quite a bit. We sailed around the Canadian Gulf Islands, down to Puget Sound, out of the Strait of Juan de Fuca and into the Pacific. Down that treacherous coast of Washington State, and Oregon and California and on to Mexico, with some 8 months in the Sea of Cortez. It did the job.

These things can be overthought.

I think that's a bit harsh Tony. 

Yes, it was harsh, Andrew and I apologise for that, but it seems to me that you've been asking questions here about mast building for well over a year now. I certainly remember posting links to my mast build for you a long time ago.

And the thing is, as others have recently said in your other threads about mast building questions, we don't really know the loads that a mast might have to withstand. There are good documents here (as you know and has been pointed out to you) that calculate mast requirements with significant safety factors. There's the table in Practical Junk Rig; there are opinions from very experienced junk rig sailors. At some stage, you have to make your decision and go for it. Nobody is going to tell you that your mast will withstand anything that's thrown at it, because we don't know what conditions you might meet.

But, once more, if you want to go down the tried and tested and easiest route, look at the text on pages 128 and 129 and the tables in PJR on pages 130 and 131. Accept what some very experienced sailors have said about using those tables minus 10%. Use the mast calculator (posted earlier) to calculate the strength of the mast indicated in PJR for your requirements, then using same calculator, find the equivalent strength of whatever material you're thinking of using. This will give you some dimensions. And they will be ok.

If it helps. I designed my masts with the PJR minus 10% method. I just glued some wood together and planed it to those dimensions. I've now sailed over 4000 nm with this boat and have never doubted the mast strength. They are splendid!

Andrew wrote:

David wrote:

I encourage you to make your own calculations and decision, Andrew. That's why I wrote this out, some years ago:

https://junkrigassociation.org/junkfaqs_masts

The section on aluminium tubes is still valid.

Thank you David. I will study it, I know you've done a lot of work on stepped tubular masts so its good information. 

I'm pretty sure I've posted this before, but this calculator is worth its weight in gold!

https://jrcalc.oscarfroberg.com/

Anonymous wrote:

Anonymous wrote:

Is this likely to be strong enough for a 10m mast on my Sabre 27? Thanks.

It looks hopeful. Who drew the plan? it certainly looks like somebody who had an idea about what they're doing. Or did you draw it yourself?

Hi Tony, I drew it myself. I do a lot of CAD work.