Removing Bow Thruster for maintenance

[Sailing Drummer]

I hope this is the right forum for this.

I'm having trouble with my bow thruster and I hope someone can point me in the right direction (just realized what I wrote - no pun intended). I'm going to also post this on another forum.

Here's the situation. The thruster fitted on my Moody 425 is a Rheinstrom. I am trying to remove it so I can have it rebuilt. The problem is I cannot separate it from the piece it is bolted to. I have removed the nuts off of the bolts but the thruster will not budge. I've tried PB Blaster. I've tried tapping on it to loosen it up. I even tried to use a scraper to wedge between the 2 parts and it won't budge! The picture is of the joint I'm trying to separate.

Am I missing something or is it simply "stuck". Any help would be appreciated.

Thanks, Larry

[Sailing Drummer]

Sorry, forgot the picture

[UNCIVILIZED]

Sounds like you tried some good, standard methods thusfar. From here I'd try getting a better look at all of the components, the fasteners, & how everything's mounted. Both via an inspection mirror, & a borescope set to record. Which, they even make cheap attachments for smart phones that allow you to use them in this capacity. And if said footage doesn't help you, maybe it'll help us or someone else to diagnose what the glitch is.

Also, some better (still) pics of everything wouldn't hurt, if just to see what's attached to what. Clearances for working, & or removing things, etc.

And is there any way to see what's going on inside of those housings? If even only via a fiber optic style borescope camera. As what may be going on is gears, or splines, fitted to drive shafts or connecting gearboxes to the bits that turn (the actual thruster/it's prop) have corroded a bit, & now are frozen together. Which, when new they likely were an easy, or snug, slip fit. But thanks to the marine environment, now "many parts are as one". As I've certainly seen examples of this in windlasses & such.

BTW, what's the manufacturer say?

PS: If it were a pulley, a prop, or if there's enough clearance in there, I'd be thinking of using a prop puller or similar.

Oh, & sometimes putting the nuts on & cranking them up REAL tight helps. As it acts to free up stuck splines & such, albeit in the opposite direction. But it can at times be enough to loosen things sufficiently to be able to pull them apart. After removing the nuts again of course.

[Dockhead]

What makes you think that it will come apart there, just like that? Do you have a manual and assembly diagram? The lower part is not "some part it's bolted to" - it's a part of the bow thruster -- it's the drive leg.

I would say that the motor shaft is likely circlipped at the far end, or has a nut on it, and that this is what is holding it together. Just because you see bolts in the housing, doesn't always mean that's all you need to do, to get it apart. If not this, then the motor shaft may be seized in whatever it fits into.

If I were you, I would try to find a way to take the thruster out, which does not require separating the housing like you're trying to do. It is unlikely that it was installed that way, by the way -- it will have been installed with the drive leg attached.

[Sailing Drummer]

The reason I think it comes apart is because I looked at a few youtube videos from Vetus and that is how their thrusters come apart. And then I looked at mine and it looks like the same type of arrangement.

I do not have any info from the manufacturer. This was on the boat went I bought her about 6 years ago. From the looks of it there are 2 distinct parts: the drive/prop portion and then the motor. I looked online but could not find info on them except Exalto and that was from and old brochure. I don't think they exist any more.

The 2 parts appear to be different metals and that is why I believe they are fused together. I can rotate the prop by hand (I've heard you're not supposed to do that but I wanted to see if being seized was the problem).

There is a clip on the top to release that but that also is frozen. I was hoping I could remove the entire upper portion and take it to a shop and have them get into it.

I will be at the boat today and see if I can get some more/better pictures.

Thanks, Larry

[JOHNMARDALL]

This is John Mardall at Vetus. If you would like to send me some more detailed photographs, I may be able to help Even though this is not one of our thrusters, the basic principles are the same for most of these devices. Send me contact info and I'll send you my regular email address.

Good luck
John Mardall
Vetus Maxwell Group

[Perna]

Here are the contact details for Rheinstrom. They have assembly drawings on their website, just not for their bow thrusters, (bug strahl rooder in german). Their products do not appear to be very high tech.

You could try phoning.

Rheinstrom Pumpenfabrik GmbH

Züchnerstrasse 2a
Postfach / P.O. Box 20 13 26
D-56070 Koblenz / Germany

Tel.:: +49 (0) 261 200 752 60
Fax: +49 (0) 261 200 752 66

E-Mail: info@rheinstrom-pumpen.de
Internet: Home

[rwidman]

Originally Posted by Sailing Drummer

............... I was hoping I could remove the entire upper portion and take it to a shop and have them get into it. ..................

Or, you could have them come to your boat and "get into it". That way, you won't have to worry about how it comes apart and there's no risk of you causing further damage by trying to take it apart.

[Comix Bay]

Originally Posted by JOHNMARDALL

This is John Mardall at Vetus. If you would like to send me some more detailed photographs, I may be able to help Even though this is not one of our thrusters, the basic principles are the same for most of these devices. Send me contact info and I'll send you my regular email address.

Good luck
John Mardall
Vetus Maxwell Group

This is a good example of our boating community . And the way I would go with the R & R.

Ted VA7YQQ
Comox, BC

[captsue]

I just removed my Vetus a few months ago ... mine had a little more rust than yours ... tried everything but it would not budge ... then, my wife handed me one of her best sharpest kitchen knifes ... i placed the sharp edge on the groove and began tapping the backside of the knife with a small hammer ... the knife immediately started moving into the grove and separating the motor from the base ... i continued moving the knife and tapping all around the grove of the motor ... withing a few minutes the motor was clearly separated from the base and it lifted right off (make sure you apply alot of anti-seize on all flanges, screws, shaft, and coupling with reassembling).

[darylat8750]

Originally Posted by JOHNMARDALL

This is John Mardall at Vetus. If you would like to send me some more detailed photographs, I may be able to help Even though this is not one of our thrusters, the basic principles are the same for most of these devices. Send me contact info and I'll send you my regular email address.

Good luck
John Mardall
Vetus Maxwell Group

Good on Ya!

[Sailing Drummer]

Some good advice above. Here's what I figured out today (I think). I believe it comes apart 2 different ways. There is a clip on the top and that may be a way to pull out the motor from the housing. But that also is frozen. The bottom part that I thought should come apart definitely looks as though it is designed to do that.

I took a few more pictures today that will give a better view of the thruster and the connector. One picture is looking down on the top.

John - I sent you a pm. Thank you very much.

Larry

[Madehn]

try hitting the top of it with a sand hammer-- you can buy one at harbour freight- basically they look like a 3 or 4 lb sledge hammer but are made of hard rubber or plastic-- they have a cavity inside that is filled with sand- keeps the hammer from bouncing off when you strike something and transfers all of the energy to what you are hitting- a couple of good hard shots near the top and it may seperate. these sand hammers dont tend to tear stuff up the way a steel hammer does-- very worthwhile addition to the tool box

[Sailing Drummer]

Everyone, thank you for the advice/tips. I've tried most them but still no luck.

John from Vetus has been helping me thru email and he's taking me through a step by step diagnostic to see what the problem may be and if it's something I can do with the thruster in place. In the meantime, I'm still using a lot of PB Blaster!

John's help is a great example of how some people/companies will go the extra step to help us even when the problem is not from their company. That's one of the things that makes Cruisers Forum so great.

Larry

[darylat8750]

Originally Posted by Madehn

try hitting the top of it with a sand hammer-- you can buy one at harbour freight- basically they look like a 3 or 4 lb sledge hammer but are made of hard rubber or plastic-- they have a cavity inside that is filled with sand- keeps the hammer from bouncing off when you strike something and transfers all of the energy to what you are hitting- a couple of good hard shots near the top and it may seperate. these sand hammers dont tend to tear stuff up the way a steel hammer does-- very worthwhile addition to the tool box

Also called a "dead blow" hammer .