vetus stern thruster - use as bow thruster?

[contessaman]

I'm looking at a used vetus stern thruster and wondering if other than the mounting moulding there is any reason why I couldnt use this as a bow thruster on my long keeled yacht?

the stern thruster seems to have a grp moulding to mount on the transom of a motorboat just below a bathing platform. I was thinking of making up a grp tube in the bows of my yacht with a flange for the innards of this stern thruster. I suppose it would be deeper under water if used this way so I was wondering how bow/stern thrusters seal around the shaft and what depth its rated to?

so...

possible, impossible or uneconomical?

t.i.a.

 

[Adamastor]

Very economical solution, but I'd be cautious as to why the thruster is for sale. It may need new brushes or a new flexible coupling, but that's minor hassle.
You need to check your wiring- these puppies eat SERIOUS Amps, so you need to be prudent. The good news is that the whole unit dismounts from the stern assemble, and if you glass a new tube in of exactly the same ID as the stern tunnel, the unit bolts in place with two bolts and a single hole in the through-tube. Be warned though that the tube is somewhere around 5mm wall thickness, so your local plumbers definitely won't stock it!
PM me if you have questions.

 

[contessaman]

Very economical solution, but I'd be cautious as to why the thruster is for sale. It may need new brushes or a new flexible coupling, but that's minor hassle.
You need to check your wiring- these puppies eat SERIOUS Amps, so you need to be prudent. The good news is that the whole unit dismounts from the stern assemble, and if you glass a new tube in of exactly the same ID as the stern tunnel, the unit bolts in place with two bolts and a single hole in the through-tube. Be warned though that the tube is somewhere around 5mm wall thickness, so your local plumbers definitely won't stock it!

PM me if you have questions.

thanks, encouraging stuff. I would intend for it to share the windlass battery up in the bows anyway and would run starter motor gauge cable so that side of things should be okay. Im pretty handy so things like brushes and bearings if user servicable shouldnt be beyond me. I have seen some off the shelf tubing available but its not cheap. I was wondering about using some cardboard tube (carpet roll?) as a mould and laying up my own tubing to keep the cost down as I still have half a ton of biaxial cloth in my garage. could even chop out the flange from the stern assy and glass it in to my tube. So we reckon the shaft seals or whatnot are up to the deeper immersion encountered as a bow thruster? is this stern to bow thruster conversion something you have done before?

ta

 

[Adamastor]

You shouldn't have too muck bother if you want to lay up your own tube IF, and it's a big "if" you can get a suitable finish on a core. The real hassle is getting the right diameter- either 150mm or 185mm, I'd say. The trick to achieving the thrust they do is that thruster impellers have negligible clearance at the outer edge of the impeller. The thruster leg is engineered to achieve these tolerances through a known wall thickness, but what that thickness is, I have NO clue!
The rest of the unit is not a worry. I'm just a little concerned that you could compromise the hull structure, because a tunnel is basically an extension of the hull. And there my knowledge sputters to a stop...

 

[contessaman]

cool. yeah I noticed that there is very little clearence between the impellor and the tube. Whilst im comfortable laying up tube and merging it into my hull without compromising the strength of the hull, I doubt that I could get the clearence right on the impellor, so my only way would be, (assuming the stern thruster fairing that the used unit has is itself fibreglass), retaining that part for the bit that houses the impellor and glassing my homemade tube into the existing moulding.
you have certainly answered my question on the motor unit anyway so thanks for that!

well the rest is a pipe dream for now (no pun intended!!) as said stern thruster is an online auction. we will see how it goes... that said, stern thrusters do seem to come up and they almost always sell for a lot less.

thanks for your help!