cadmunkey

Hi,

I've had this boat for some time now, and it has gone through a few complete mechanical and 1 cosmetic refit since I built it almost 10 years ago. She is getting very close to running perfectly except she has little to no steering control while she is in reverse. I'm wondering if anyone knows a way to get better control in reverse out of a single shaft setup.

I'm using a 3 blade 40mm prop and the rudder is 0.75mm brass as seen in the picture.

Cheers,

DONS BOAT WORKS

My Feedback: (3)

Nice looking boat.
I would try a bigger rudder.

Umi_Ryuzuki

Two rudders in front of the propeller on either side of the shaft?

[&:]

cadmunkey

I was thinking of a rudder in front of the prop, but that would be harder to do and would impede the flow of water to the prop when going forward. I'm thinking of making an extension for the main rudder just to see what happens. really I want a bow thruster, but my boat is too small to house it and the extra required components unless i build a very small one that runs on a servo motor. HMM. I think I have an idea for a fun little project. Micro bow thruster. Would be quite easy to build out of styrene.

Cheers,

Umi_Ryuzuki

The rudders may cause a bit more drag, and the boat will lose some speed, but I don't think they would
impede the flow of water to the propellers. Quite a few push tugs use a set of reverse steering rudders
to aid maneuverablity.

However, we like to see build ups, and seeing you build a micro bow thruster will be fun.
A bit of tube, a bit of paddles.... We want pics!

cadmunkey

Looks like I have a project for tomorrow. Ill make sure to take a bunch of pictures. How big of a moter can you run of a standard servo board? Do you think I could put an amp through one?

I've got one of the graupner bow thrusters but it is way to big and would sink my bow way to much.

Cheers,

mfr02

I would not go bigger than the standard motor as fitted. Thats what the board was designed for. If you consider using a buffer amp to take the servo electronics output and buffer and amplify it, depending on what transistors you pick, as far as motor choice is concerned, the world's your lobster.
To make a single screw, single rudder boat steer in reverse you need to go a bit radical. Either a Kort (OK on tugs) or got to twin shafts/rudders/motors and controls. Maybe an azipod.

mrboats

Hi, and good luck on steering in reverse. I have had several 18-25' single screw boats, and backing is tough. They have outdrives, which helps. You may notice that the boat "prop walks" in reverse....if the rudder is straight, the boat will tend to back either to the right or left depending on rotation of the prop. You can use this property to dock and do maneuvers with your single screw. I have several Dumas runabouts, single screw, and they dock well using prop walking. Practice, and it works. See you on the pond. A larger rudder will also help, and you can make it a clip on so you can remove it for display.
Regards,
JJ

cyclops2

Large rudders and a LONG keel work best.

Rudders are determined by looking at side veiw of a boat. It needs to look big enough.
The keel is about 2 to 3 X rudder area.

These sizes work in moderate wind & 1/2 throttle.

rye

My Feedback: (10)

hi
this could work a lot of work but doable rye
http://www.vac-u-boat.com/Vac-U-Tow2.htm

cyclops2

A good and bad example of rudder designs for the same job, are ELCO & Higgings PTB rudders.

You tell me who had no money left to make the rudders big enough?

Or who was so desperate to have the highest top speed, that it could not handle for evasive gunfiring and bomb runs?

The good boat was a "shoe box " with a point at 1 end........Higgings.

Looked DUMPY next to a Kennedy ELCO. ......Not many Higgins were sunk easily. They were a boat that you held on to with all 4 hands, in evasive action.