Two and a half questions
 

I have just finished making my trimaran. It is one meter long, even though the hull is only 6cm wide.


I copied this from a picture, but the one in the magazine was actually half this size (with a 400 motor). What size monohull would you recommend for a speed 600 motor, 45mm propeller, 7.2V battery pack etc.

Do you have any free plans for a model this size?



My trimaran has a speed 600 motor, a 45mm surface piercing prop, and a 7.2V battery pack. I tested in the bath, and it is extreamly powerful.

My question is: Even though the propeller comes out the back of the boat, can you have the rudder coming through the floor of the boat - in front of the propeller? This boat previously had a 540 motor and 30mm prop. It was rubbish.

But can I have: The rudder in the same posision as in photo 1, but the propeller in the same place as in photo 2?

Photo 3 is the overall boat with the watercooled speed 600 motor.

Andrew


p.s. - I am 13 and my income is £3 a week

RE: Two and a half questions
 

Hi
Quite the project you have going there. We call boats like that Riggers over here. As in out rigger. Since the boat will pivot at the rear of the sponsens to turn, I suppose the below hull rudder will work .I have not before seen this done. Since the rudder is centered and the prop shaft needs to be in the center too, how are you going to do that? I think your 45mm prop is too big for the motor. n.h.schmidt

RE: Two and a half questions
 

I plan to have the rudder slightly off center.

About the prop size, in the bath the motor runs cooly, and also I discovered that the really cheap boats of ebay (with 2 380 motors) have 45mm props. They apparently can go over 20mph.

When the boat is sitting in the water, about one third of the top blade of the prop is out of the water.

Andrew

RE: Two and a half questions
 

Start with a smaller prop and work your way up. I think NH is right about your prop being to big. Riggers pull more amps than other boats do, and with even a slightly bad setup they'll pull even more amps. Don't let your bathtub testing fool you, that's not real running.

Did you ever get some good cells, or are you still trying to get away with AA's?

RE: Two and a half questions
 

I am using 7.2V 1700mah racing packs.

In the bath, the motor draws 10 amps.

RE: Two and a half questions
 

Hi
Everything I have heard about the two 380 powered boats on Ebay has been very bad. The most popular, the NQD Speed Snail is not even going much over 10mph. We can't stop you from giving it a go with what you have. Maybe it will work . n.h.schmidt

RE: Two and a half questions
 

Well, I was not thinking of buying one of them. I will test my boat in a lake this week.