No amount of (plastic) tubing will withstand the chafe you'll be looking at during a worst case scenario storm laying behind your JSD.
The idea with the steel wire makes most sense if you intend on using the cleats
. But whatever way you go about it, take a good look at the design loads on the JSD website. This is of course the worst case breaking wave strike, but imagine similar loads hammering the rig every wave that comes along for hours and hours and hours on end. Check the cleats
for proper backing plates
, check the deck
for structural integrity, check everything for the maximum design loads of your JSD.
Personally on my steel yacht, I'm drilling a hole in the toerail, and using big shackles to attach the bridle legs to the holes. This way, no chafe is possible, and the hull
itself is used to dissipate the load. Then I'm using steel wire to attach the shackles to the samson
post on the stern (this goes through the deck
, and is seated on the ribs and welded there as well as to the deck).
I made my JSD myself, so in the light of the chore it has been to make the whole thing, making sure the attachment points are solid is only a little bit extra work
. And to be honest, it's the most important imo. I'd rather have half my cones fail then one bridle attachment point.