Krogen 42 paravane A-frame tube size

[Bryanjw]

I am having a local fabrication shop replicate the A-frame paravane tube size on boats such as HOBO. I understood the A-frame was 3 inch schedule 80
6061-T-6 aluminim, and the outrigger poles were 2 inch schedule 80. They claim that if they use 2.5 inch schedule 40 for both, it will be plenty strong. Should I believe them? They also think a stainless plate, aft of the mast but connected to the mast with pop rivets, will be much better than a collar around the mast, to join the A-frames.

Thanks for your opinions.

Jonathan

 

[HopCar]

Richard on Dauntless is the guy you want to talk too.
He has been through it and taken his paravanes across the Atlantic twice.

 

[DavidM]

The idea of a gusset plate pop riveted to the masts to hold them together leaves me cold. It can't possibly be as strong as a collar.

Which also makes me suspicious of their diameter recommendations.

David

 

[FF]

Use the line or chain size that hooks the paravanes to the boat as estimate for loads involved.

 

[Sealife]

Mounting the plate or arms aft of the mast will get in the way of the topping lift for the boom, as it originates at bottom of mast going through pulley at top of mast all in the back.

A frame is 3", arms are 2 1/2" sch 80 not 2".

Strong enough, I don't know. But the difference in price is a small percentage of the total project. Why risk it?? I might look at a different fab shop, sounds like they may be trying to make it easier for them. The collar was a pain in the ass to get all the angle just right.

If you go with Richard's setup, be aware of some of the short comings which he will gladly discuss. We compared the two boat in San Blas Panama last year.

 

[JDCAVE]

...A frame is 3", arms are 2 1/2" sch 80 not 2"....If you go with Richard's setup, be aware of some of the short comings which he will gladly discuss. We compared the two boat in San Blas Panama last year.

My A-frame is 3.5" and poles are 2.75". Not sure of the tubing type, but it is aluminum.

In my opinion the A-frame is the better design. I'd be careful of anything that has not been designed by someone who understands the stresses on the system.

The collar:



Jim

 

[JDCAVE]

Oh...and another thing. Change the stainless rigging regularly...every 5 years. The stuff is cheap...why wouldn't you change the rigging from time to time.

Jim

 

[Bryanjw]

Thanks

Thanks for the replies, I really appreciate it.

Jonathan