Chris Doran of Newcastle, NSW asks:
I would like to know, firstly, with the paravanes, how much strain is there on the mast, or is most of the strain taken on the front shrouds? Secondly, how deep do the fish swim, and is the height above water - at the attachment of the base of the outrigger to the vessel - critical to the performance of the system? I am considering installing outriggers to our vessel, however the mast is stayed from our cabin roof, hence my question.
Jim Leishman responds:
Chris, the loads on the stabilizing gear are significant however they're not as much as you might think. The rig of a typical sailboat will put the spar under greater compression and the shrouds under greater tension that the Paravane rig will. One important difference between the sailboat rig and the Paravane rig is that the Parvane loads are cyclical and we have had problems over the years with chainplates working loose. We use strong backs which are under tension then compression.
There is a method to calculate the loads and it can be found in Voyaging Under Power - all editions. I would suggest that you consult someone with some engineering knowledge before retrofitting a system to your boat.
We run the fish at 15 feet below the waterline when the boat is not running. Underway they stream aft and run shallower.
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