Size of support needed

[CapnCrunch]

Originally Posted by Cheechako

What size are the davit "arms"?

Davit arms are 3/4" stainless rated for 150# lifting, each. They extend 4' out from the back of the fb.

[Eigenvector]

Ok. Here's a spreadsheet to calculate the size of tube/pipe. The design will probably be driven by aesthetics and not stress.


Had to convert to an older format to upload.

[CapnCrunch]

Originally Posted by Eigenvector

Ok. Here's a spreadsheet to calculate the size of tube/pipe. The design will probably be driven by aesthetics and not stress.

Had to convert to an older format to upload.

Wow! That's cool. Thanx! If I change the tube dimensions to 1.00 o.d., it bumps the Critical Buckling Load up to 917 which is pretty close to the recommended max load of 1000. So, if I add the inner 7/8" tube, I should be pretty safe.

[Eigenvector]

The calculations are for a single strut which gives you a safety factor of 2 since you have 2 struts. If you leave the g loading at 2, you should have a SF=4 in calm seas.

[CapnCrunch]

Originally Posted by Eigenvector

The calculations are for a single strut which gives you a safety factor of 2 since you have 2 struts. If you leave the g loading at 2, you should have a SF=4 in calm seas.

OK, Cool. I'm pretty comfortable with the plan of two tube-in-tube supports. T

The only remaining question is does anybody have any suggestions on how to keep this contraption from rattling?