6ft Skiff

Originally posted by tickel Funny you should say that. At the Dinghy Show my son ( sails a Moth now) and I were talking to Mark Giles designer of Lightning and Supernova. He maintains that a torpedo which is totally submerged has almost no resitance,

Well, what a submarine doesn't have is wavemaking resistance, because it doesn't create waves. I think other kinds of drag increase though. Need a *naval* Naval architect here really, but I rather suspect that wave making doesn't magically go away when a vessel is submerged, instead it depends on how deep it is. So your submerged boat probably has to be pretty deep to eliminate wave drag, which in turn means you need a lot of sttructure to get up to the surface where crew and sails are, which in turn creates other sorts of drag...

Originally posted by JimC Originally posted by tickel Funny you should say that. At the Dinghy Show my son ( sails a Moth now) and I were talking to Mark Giles designer of Lightning and Supernova. He maintains that a torpedo which is totally submerged has almost no resitance, Well, what a submarine doesn't have is wavemaking resistance, because it doesn't create waves. I think other kinds of drag increase though. Need a *naval* Naval architect here really, but I rather suspect that wave making doesn't magically go away when a vessel is submerged, instead it depends on how deep it is. So your submerged boat probably has to be pretty deep to eliminate wave drag, which in turn means you need a lot of sttructure to get up to the surface where crew and sails are, which in turn creates other sorts of drag...

Yep, that's correct.  Subs obviously have no air/water interface and therefore don't suffer from wavemaking resistance in the form of a conventional bow wave. However at shallow depths a wave will form on the surface. Also, if not deeply enough submerged the hull can broach the surface due to wave motion, surface suction effect and changes in water density (e.g. sailing past a river estuary). At slow speeds control can be very tricky. You also end up with a much higher wetted surface area, increasing resistance at low speed. That's not to say the concept couldn't be made to work for a dinghy, but its not as simple as it might sound, and to say they have almost no resistance is exaggerating.

There are a few on there, but they are a bit few and far between. No close ups found as yet i don't think...

http://www.6ft.flatwater.co.uk/index.php?option=com_content& amp;task=view&id=5&Itemid=30

Photos of the original 6s are EXTREMELY hard to come by... what you see on the history page is pretty much all we've managed to get our hands on since november time.

As for torpedo hulls...





Edited by Isis

Originally posted by Rupert Weren't there pics on the Moth site a while ago of something that was trying the torpedo thing? I seem to remember that turning corners was a bit of a problem...

 

were you thinking of this:

 

more info at http://www.int-moth.org.uk/DesignsLittleWing.htm

 

Edited by Chris Noble