Good luck with the build Frederik

Frederik wrote:

Here we go...

Fantastic to see the work starting, Frederik.  I am so looking forward to seeing your boat take shape.

Hem, Frederik,

that tent doesn’t look like a warm place during winters in Denmark. Have you found a glue that will work down to frost temperatures?

Arne

Anonymous wrote:

Taking the maximum rightning moment of the boat as starting point of the mast calculations  makes the most sense to me.  Times 3 as safety factor. Eric Sponberg does the same.

Then again... what about the mizzen mast....

Sponberg's article on designing free standing masts:

https://www.ericwsponberg.com/wp-content/uploads/design-engineering-masts.pdf

Anonymous wrote:

Thanks for the replies.

Arne. 

Are you using modulus of rupture in your calculations? For a 310/62 mm hollow spruce that would be 72 Mpa with a breaking strength of approx. 16300 kpm...

 I picked the strength of spruce from Ian Nicholson's Boat Data Book.

There were three numbers to pick from, tearing force, crushing force and breaking force. Not knowing what to choose, I picked the 'weakest' one, the crushing force at 45MPa. If I had chosen 71MPa instead, then the breaking moment would rise from 11600kpm to around 18500. I have later looked up data about wood, and my 45MPa are most probably on the low side. However, I have just used local trees for masts, not knowing how good quality they were, so I my thinking was 'Better safe than sorry'...

Arne

PS:
As early as in 2006, I had a go on finding the strength of wooden masts. I have later 'refined' the way to guess the righting moment of the boat, but apart from that, the write-up still makes some sense, hopefully. 
The uncertain factor is the strength of the wood material.