Model Boat Mayhem

Technical, Techniques, Hints, and Tips => The "Black Arts!" ( Electrics & Electronics ) => Topic started by: CF-FZG on July 30, 2011, 11:57:24 pm

Title: Which bow thruster?
Post by: CF-FZG on July 30, 2011, 11:57:24 pm
I'm going to need a bow thruster for my lifeboat, and I'm not sure which make to go for.

They're all around the same price so that's not a concern, but which one?? - the ones I've found so far are the Graupner, Robbe and Raboesch units.

Any recommendations appreciated, (preferably with reasons :-) )


Thanks,

Mark
Title: Re: Which bow thruster?
Post by: CGAux26 on July 31, 2011, 12:11:28 am
I have a Raboesch in my Loyal Volunteer (40" LOA, 23 lb displacement).  It's the middle size one of their 5 size range.  It moves the bow around quite well.  One problem:  the plastic paddle is just a press fit on the motor shaft, and I managed to spin it early on.  Had to replace it with a brass paddle.
Title: Re: Which bow thruster?
Post by: CGAux26 on July 31, 2011, 12:14:40 am
I hit SEND too early.  Here is a picture of my BT after the paddle was replaced.
Title: Re: Which bow thruster?
Post by: Peter Fitness on July 31, 2011, 02:40:21 am
One problem:  the plastic paddle is just a press fit on the motor shaft, and I managed to spin it early on. 

I had a similar problem with the Raboesch thruster in my Armidale class patrol boat, but cured it by removing the paddle, putting a drop of superglue on the shaft, then quickly replacing the paddle. That was about 10 months ago, and I've had no further problems. The brass paddle looks good, though O0

Peter.
Title: Re: Which bow thruster?
Post by: nhp651 on July 31, 2011, 08:40:33 am
is there one that does the proper propeller rather than a paddle, as I want to put one in my Severn lifeboat
cheers,
neil.
Title: Re: Which bow thruster?
Post by: triumphjon on July 31, 2011, 01:07:41 pm
is the paddle a common fault ? only ive just fitted a raboesch mini thruster in my tug that has a four bladed paddle !
Title: Re: Which bow thruster?
Post by: colin-d on July 31, 2011, 05:45:02 pm
there is a propeller bow thruster from Raboesch but its rather large and rather expensive..!!

Raboesch Prop bow thruster (http://www.deansmarine.co.uk/shop/product_info.php/cPath/35_38/products_id/812) (click me link)

the normal bow thruster from Grauper is also not bad at all, similar to the raboesch normal paddle thrusters but i have never had these paddle problems with the Gruapner thruster, like some have had with the raboesch ones.
Title: Re: Which bow thruster?
Post by: nhp651 on July 31, 2011, 06:54:10 pm
thanks for the link..found them also on Cornwall model boats site.
i prefare the prop driven one to the paddle type.more scale like for the Severn lifeboat

cheers neil.
Title: Re: Which bow thruster?
Post by: CGAux26 on August 01, 2011, 12:57:00 am
After maybe a dozen successful runs with my brass paddle, I got something solid stuck in it and spun it on the shaft, too.  Took it out and filled the tube with epoxy and crimped the tube to the shaft with a vice.  So far so good again.  But this points out the need to provide maintenance access to the screws that hold the motor in place.  On the Loyal class tender there is a small hatch way forward under which I located the BT.  A l-o-o-o-ng Phillips screwdriver will reach the screws.
Title: Re: Which bow thruster?
Post by: hopeitfloats on August 01, 2011, 02:00:06 am
I hit SEND too early.  Here is a picture of my BT after the paddle was replaced.

with the paddle not being in the centreline of the shaft does that cause any vibration through being off balance.
Title: Re: Which bow thruster?
Post by: Peter Fitness on August 01, 2011, 02:30:22 am
The paddle is on the shaft centre line, or it is on  mine.

Peter.
Title: Re: Which bow thruster?
Post by: 6705russell on August 01, 2011, 06:42:23 am
I fitted the propellor type in my 1/12 Tamar, much better than the paddle type...

Russ
Title: Re: Which bow thruster?
Post by: hopeitfloats on August 01, 2011, 10:29:51 am
just looking at the brass one peter, not the original :-))
Title: Re: Which bow thruster?
Post by: wartsilaone on August 01, 2011, 11:04:36 am
I do like the props on your Tamar Russ, looks so much more realistic. I too have had something get into the the thruster tube and then had to replace the paddle. A grill over the hole would be handy.
Title: Re: Which bow thruster?
Post by: CGAux26 on August 01, 2011, 11:10:02 pm
Yes, it vibrates a bit with the brass paddle off center.  And I had no way to balance the paddle.  But with the BT only running 10 or 20 seconds at most at a time, and maybe 2 minutes total out of a 1.5 run, it is no big deal.