Motor Mount – How Do I Get the Right Angle

[Alan SimParticipant @alansim14280]

Hi All

 

I have a boat I bought off ebay and I am changing the motors for bigger ones.

 

I have cleared the hull (Fibreglass) of all the debris,and bought the new motors but how do I work out the angle of the motor mount so the coupling lines up?

 

I have thrown away a lot of failed attempts,there must be a better way,please help.

 

Alan (Frustrated)

 

[Alan SimParticipant @alansim14280]

[Ian GardnerParticipant @iangardner62867]

One way I have seen described is to run the motor on the least voltage that will turn it and measure the current drawn with an ammeter- the least current is the best angle. This is described in The Complete Marine Radio Control Manual by Hugh Bright, I think. Personally I tend to eyeball it and turn the motor by hand to feel if it’s smooth.

Not much help to you, but on a wooden boat it’s good to arrange the motor mount before planking or skinning the hull to help with visual alignment. I think you can also buy solid couplings for the purpose of aligning shaft and motor.

Good luck,

Ian

[nevinsParticipant @nevins]

Thats interesting to read Ian, I normally tend to try and get the motor and prop to run so that the angle of said items is at its least, so that there is the least amount of throw on the set up there fore decreasing the vibration on the shaft.

 

I’m not saying this is the right way but it works for me and being a mechanic I know that this method is true to a cars prop shaft.

Gareth 

[Alan SimParticipant @alansim14280]

Interesting reply which I had not thought of however,I need to know how to fashion the wooden bearers that the motor mount will be screwed to,I can’t get the angle right with trial and error,more error than anything else.

 

Surely there is a way of doing it,pity I don’t have the plan.

 

Alan

 

[Bob Abell 2Participant @bobabell2]

Hello Alan

 

There are many ways of installing motors………Have a look at my suggestions……..

 

Screw the motors, side by side onto a small baseboard.

 

Fit a 3mm packer below each motor mount……..(for emergency adjustment later)

 

Assemble the couplings and prop shafts to the motors

 

If you have plenty of space available inside the hull, extend the motor base to allow the prop shafts to be aligned properly whilst still on the bench, by fitting suitable packing pieces under the prop tubes

 

Cut the holes in the hull stern and fit the complete assembly into the hull, with the prop tubes protruding

 

The complete assembly can now be adjusted, up and down, until it looks right

 

Cut a cross support to go across the hull and when you`ve decided that the angle is ok….glue the support to hull sides, using epoxy

 

That`s just about it really

 

All the best…..Bob

[ashley needhamParticipant @ashleyneedham69188]

Use a double coupling. No worries.

 

Ashley

[David MeierParticipant @davidmeier28154]

Hi Alan.

 

A method I have done quite successfully is to make the wooden block mount a bit lower than required then put a dollop of auto body filler on top of it and bed the motor onto the body filler until it lines up as you want it. when the filler has set you can clamp the motor onto it to secure it with a simple strong back to secure it. PS. you need to wrap the motor with glad wrap (cling film) to stop the filler from sticking to it.

 

David.

 

   

[Paul TParticipant @pault84577]

One way I have seen described is to run the motor on the least voltage that will turn it and measure the current drawn with an ammeter- the least current is the best angle. This is described in The Complete Marine Radio Control Manual by Hugh Bright,

 

This is the method that I use.

 

Paul

[Ian GardnerParticipant @iangardner62867]

Further to this, there was an article in MB recently describing all sorts of motor mounts, can’t remember which issue (Colin?) but another thing I like to do is use silicone rubber. Build a box for the motor to sit in, perhaps chock it up to the right level with slivers of wood and then set the motor in a large dollop of silicone sealant- you can wrap the motor in cling film to stop it setting in, although  I have done both. The motor can be held in place with hooks and rubber bands, I have used O rings too. It makes a nice quiet system. One of my pet hates is noisy electric boats.

One thing, the last time I did this the silcone took about a week to go off- I don’t know whether the stuff has shelf life but I don’t remember this being a problem in the past, so might be good to start with a new tube!

Finally, you can buy really nice machined mounts for most sizes at very reasonable prices- cue Mr Milbourn!

 

Ian

[Alan SimParticipant @alansim14280]

Hi All

 

Many thanks for the replies.

 

Lots of ideas to have a go at.

 

Alan

 

[TelstarParticipant @telstar]

Hi Alan

A method of aligning motors I used, initially with IC’s, but easily adapted for any motor, was to draw on a piece of card the outline of the motor (end on) marking the position of the shaft, and mounting centers.  Then make the motor mount so the card template sits comfortably in the mount. then hold the mount assy. in the hull with blue tack or similar and shine a light up the stern tube with no shaft in , (I use a cheap keyring lazer pointer) placing the template in position adjust the mount assy until the light shines on the mark on the template for the motor shaft. Move the template along the mount to check if the mount is in line. Once everything is aligned you can then fix the mount in place

 

Cheers Tom

 

[TelstarParticipant @telstar]

Sorry sketch didn’t work, try again

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