Quote:
Originally Posted by Tupaia
Probably not as efficient as "Kite Boat Systems" www.Kite-boat.com or Sky Sails www.skysails-yacht.com that both use parafoils but looks a whole lot simpler and cheaper.
My only concern would be the length of line from the mast head and the force that could be exerted high up if the deck level line was released or let go by accident. Does the mast head line attach to the bridle of the parachute or the rim and is this line loose when the para is flying?
I assume you could have an extra length of line equal to the height of the mast to keep things off the deck that attached to the existing spinnaker halyard. But that would still leave the parachute lines themselves to deal with.
|
both lines are always tight, if the lower is really loose in above 10kn wind then your top line is too short (mostly) or your lower line to long. only in very light wind if the parachute is stalling a bit the lower line gets loose for a small amount of time. but in general lower line loose means you have no forward movement by the sail.
if you release the lower line the parchute colapses and no forces to the deck. thats what you also do (first pull top line in till mark on the top line) incase some of the little line break because you overloaded the sail.
but put a figure 8 at the end of the lower line so it cannot completly go out, because thats the absolute worst case because then you have a collapsed parachute flying at about mast height with the lower line flying up in the air.
then you whinch it to the mast with hailyard and put out genua to produce windshade so it stalls and comes down...happened to me once in the beginning but because the lower line is heavier that comes down first which after some attemps you are able to grab, put back onto bow roller and
winch tight so it inflates again.
the worst that can happen is you operate it wrongly in strong winds and have a by far too short top line and a too long lower line that the sail creates a lot lifting forces to the lower line and deck where its connected. i done that on purpose with my old
ketch to further reduce rolling but you could have lifted the whole 12t boat with this bow roller alone
both ropes (Hailyard and bottom line) i use have more braking strength then the each 10 little line together connecting to the cloth of the parachute which will rip before your lines do.