Yea but look at the boards they must be close to two meters in length... <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />
"House prices have risen by nearly 25 percent over the past two years. Although speculative activity has increased in some areas, at a national level these price increases largely reflect strong economic fundamentals." – Ben Bernanke – 2005
The bruce foils are in a very horizonal angle and seem to have no raising/lowering controls. My guess is that one would trapeze out to insert the board and move it, like they do in boats like mine to put the boards in place (although we have lines to control the boards). Those foils have to be reinfoced (= heavy) to withstand important bending loads, so the task is far from easy.
All that said, I really hope they succeed. A self righting foiled tri would be the first multihull to have real potential to send monohulls to the museum, from dinghys to maxiyachts. So lets think positive:
I hope they figure out a better way, but if everything else fails, explosive pins could solve the problem of releasing the beam locks.
The most difficult remains the system to fold the amas under the capsized boat in order to lift the mainhull out of the water.
A solution I figured out would be to lead both (syntetic) shrouds to the mainhull, where an electric winch would tension them simultaneously. That would require a strong mast, with extra stays. And I am not sure if it would work. Any other ideas?
Luiz
Re: eXploder 20
[Re: Luiz]
#100005 03/08/0702:51 AM03/08/0702:51 AM
Are there any realistic and tested alternatives to their righting method? How long a Solo~Right would you need to right this one Gary <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />
Why could you not pull them up by simple pulling them [the AMA's] together? [towords each other] or via the mast, pulling them towards the mast with the attachment only at 2 mtr [7ft] high
The load is maximum during the first ten or twenty degrees folding, when we are starting to lift the mainhull and tramps (together with the water that entered the mainhull), from the water surface.
Now that you mentioned pulling the amas together, I guess the best way to do it would be with a pulley connecting the shrouds about 2 o 3 meters high. The mechanics of this system guarantys maximum tension in the shrouds when the pulley starts to be tensioned, exactly when we need it. Later, as the shrouds are deflected by the pulley, the tension is progressively reduced.
I'll try to sketch the idea and post it.
Luiz
Re: eXploder 23, a Trimaran
[Re: Luiz]
#100008 03/08/0710:44 AM03/08/0710:44 AM
That sounds alright. Pulling them together from the chain plates would probably work, although it would be an unstable geometry (a trapezoid) and would move around a lot. The risk would be damaging something with the whole boat twisting around uncontrollably.
That sounds alright. Pulling them together from the chain plates would probably work, although it would be an unstable geometry (a trapezoid) and would move around a lot. The risk would be damaging something with the whole boat twisting around uncontrollably.
Unless you only moved one ama at one time and then could lock it in the up position somehow.
Also in favor of a video. The attachment shows a system that should work. A pulley between the shrouds and another between the amas. The geometry makes the first pulley extra powerfull, which is necessary to sink the floats and lift the mainhull out of the water.
Luiz
Re: eXploder 20
[Re: Luiz]
#100014 03/09/0708:56 AM03/09/0708:56 AM
Also in favor of a video. The attachment shows a system that should work. A pulley between the shrouds and another between the amas. The geometry makes the first pulley extra powerfull, which is necessary to sink the floats and lift the mainhull out of the water.
So the mainsail would have to be down? I didn't really think about it, but that alone could be very tricky on a capsized tri.
Jake Kohl
Re: eXploder 20
[Re: Jake]
#100015 03/09/0710:27 AM03/09/0710:27 AM
So the mainsail would have to be down? I didn't really think about it, but that alone could be very tricky on a capsized tri.
Godd question, I didn't think of it.
I guess the shroud's pulley would be almost aft of the mainsail. The risk of tearing the sail is reduced if the mainsheet is released, but I wouldn't bet a sail on this.
Without a vang one could pass the pulley under the boom. As the pulley is tensioned, the boom sinks, further releasing the sail. This would probably do the trick.
Quote
I want to know who is going to swim down to pull the red pulley?
I guess this is a task for tha skipper who returns from the trapeze to the tramp to adjust the mainsheet... Or maybe for the crew who does the same to adjust the jib... <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />
Or run the line in front of the mast between the two shrouds...
The mast could break if the chainplates for the shrouds are too far back (the pulley would make an angle in the mast) and if the boat is heavy, which would require more tension in the pulley to raise the mainhull from the surface.
Luiz
Re: eXploder 20
[Re: Jake]
#100020 03/12/0711:39 AM03/12/0711:39 AM
Just thought of a different problem: if everything we devised works, the boat will not be righted, it will seat sideways. After all that work, one would still have to stretch the amas again in such a way that the boat doesn't capsize again.
Luiz
Re: eXploder 20
[Re: Luiz]
#100021 03/12/0711:52 AM03/12/0711:52 AM