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Rudder placement on hydroplane design

Posted: Sun Nov 09, 2008 2:33 pm
by jlcrowley
Hi,

I have found a design for a hydroplane using the standard BSA kit on the web. I followed the design - but I need to use all the parts in the kit. Plan says to cut a slot in the hull 1.5" from the stern and insert the keel as a rudder. Bit I don't know if that means the front of the slot is 1.5" from the stern, or the middle, or what.

If the front of the slot is 1.5" from the stern, the hull, the end of the keel/rudder is flush with the stern.

Can anyone advise as to correct placement?

Re: Rudder placement on hydroplane design

Posted: Tue Nov 11, 2008 2:15 pm
by Teeeman
sounds like you have the right interpretation, but how heavy is the keel?

If it makes the boat's nose really light... could be good or bad...

suggest testing it...

go with the best location :)

-T

Re: Rudder placement on hydroplane design

Posted: Fri Nov 14, 2008 6:50 pm
by BlackLotus
If you must use all parts, I would probably grind it as thin as possible (or drill holes in it to reduce weight), reshape it a little and use it as a spar to conect the pontoons. I would then use the rudder supplied in the kit attached into the rear spar and watch my boy speed down the gutter.

Re: Rudder placement on hydroplane design

Posted: Sun Nov 23, 2008 10:06 am
by rdlongsc
Our pack also requires using all parts in the kit. Gluing the rudder flat on the top of the hull or bottom of the trampoline has become a favorite way of meeting this requirement, especially on the catamarans, which don't need it. It becomes a "decoration" :lol: .

Re: Rudder placement on hydroplane design

Posted: Thu Feb 19, 2009 4:20 pm
by boss429
You can glue the metal "keel" on top near the back as a weight to balance the boat to push the nose out of the water. You don't need the weight underneath, the boat won't capsize.

Use the plastic "rudder" for the keel/rudder again under the back of the boat.

The hydroplane design is meant to keep the nose out of the water and minimize the amount of hull that rides below the waterline.

When you blow into the sail the boat has a tendency to tip forward so use the weight to balance the boat accordingly.