R25 Thruster Mounting

[bruceandnoel]

Pulled in for fuel last year, had a moment of excitement when my stern thruster spun up wildly but did nothing else. Yup, a blown shear pin.

Investigation once on the trailer showed that the prop was dragging on the tunnel.

Checked the Sidepower installation manual, and it says to make sure the motor is blocked up if it's more than 30 degrees off vertical.

Checked out both my thrusters - no blocking. And the prop is dragging on the top of the stern thruster tunnel, exactly what would happen if the heavy motor was to distort the stern tube. Page 3 of the stern thruster installation manual in Fig. 4 says "Motor support Must be installed". Similarly, item # 1 on the "Installation Checklist" (page 11,Sidepower Stern Thruster installation manual says " There is a sturdy additional support under the electric motor...". They seem to be seriously concerned about the need for blocking!

Has anyone else had a problem with the prop dragging on the tunnel? I've braced up the bow thruster, but I'm sure not looking forward to pulling the rear one - it looks like a real bear to get to!

Any guidance would be appreciated!

Thanks!

Bruce

 

[Kenny Marrs]

Hello Bruce,

I would check to make sure the bolts holding the gear leg are tight. If you're replacing the shear pin anyways it would be an easy thing to check. There are only two screws you'll need to tighten. If possible, I would also check the prop to make sure it's tight.

To answer your question, I've never had anyone call with this issue before. Not to say it's never happened, it's just never been brought up to me.

Thanks,
-Kenny

 

[ESCAPE]

I replaced the stern thruster moter a year ago. One of the most dificult repairs I have made to any piece of machiner in my 79 years of life.
I belive I can give you some tips to make the job a litle less dificult. Please phone me any time.

Bob Messmer
239-775-3493
2978 Orange St.
Naples, Fl. 34112
ESCAPE
Ranger Tug 25, 2007

 

[nzfisher]

I just replaced my rear thruster using this set of tips from another owner. I also built a platform with small saw horses that allowed me to lie down at the same level as the top of the bait tank rim. I also have very long arms that helped. I advise checking it regularly for tightness after you reinstall/repair the unit.

viewtopic.php?f=5&t=125#p1991

 

[bruceandnoel]

I'm new to Ranger Tugs, and only just figured out from information on this forum that there appears to be 2 "families" of thruster used on the R25 - one of which appears to be enclosed in a plastic cover, presumably for moisture resistance or to reduce the risk of accidental ignition of below-floor combustible gasses. (The other is a more conventional "open" design).

My stern thruster is the "enclosed" type, and it seems that due to the flexible nature of the plastic cover, it would be impossible to block it effectively. Interestingly enough, my installation manuals say nothing about these 2 styles.

I'm still left with the problem of the prop dragging on the stern tube, so I'm going to pull the motor and double-check the bolts holding the drive leg on. If they are tight, I'm thinking of mounting the prop on my metal-turning lathe and turning it down a bit. I'm prepared to put up with slightly reduced performance if the reliability is improved!

Thanks to all who responded to my original post!

Bruce

 

[joempo]

Bruce,
I don't know what year your tug was built, but the fact that you have enclosed thruster motors suggests they have been replaced (up-graded). Ours is a 2006 R-25. I replaced both of ours earlier this year. The plastic enclosure is pretty rigid, so you may be able to place a support under it if necessary. There is also the metal housing between the cover and the mounting flange. Hopefully, whoever removed/replaced yours previously installed "studs" in place of the original cap screws on the mounting flange.
As was suggested, follow all the links related to thruster motors on the forum. There's a wealth of information and experience here.
Joe

 

[bruceandnoel]

Hi Folks - the thruster saga continues.
Kenny was getting close when he suggested checking the bolts holding the leg on.
The bolts were tight, but I figured "I'm in this deep now, may as well try and find the problem". (I could actually see where the prop has rubbed hard enough on the tunnel to remove a bit of the plastic).

So, off with the leg (lovely piece of workmanship!) Then, ever so carefully, off with the tunnel assembly. I mocked it up on the bench, and discovered enough clearance in the leg mounting holes for some radial "adjustability". By rotating the leg ever so slightly (literally just a degree or 2), my prop clearance was now perfect all 'round. I want to be sure this little gem doesn't move in the future, so I made new gaskets for the leg base, and put the whole thing back together using Sikaflex 292. The 292 has over twice the tensile strength of 291 - sure hope I don't have to take this apart again soon!

Today I'll reinstall the tunnel on the boat, and attempt to get the motor back on. I've built a simple adjustable sling for the motor, and I'm hopeful that it will ease the installation. What a brute of a job!

 

[bruceandnoel]

Thruster motor is back on, timed how long it took, it was a relatively painless 18 minutes, not including hooking up the wiring again. Before I started, I had everything possible out of the way, and the following tools on hand:

6mm allen wrench, with the short end cut back as far as possible, leaving just a short "hook".
7/32" allen wrench, with the same mods as the 6mm
Lightweight flat tie-straps (2). Mine came from Harley motorcycle crates, used in shipping.(Free!)
9/16 inch long-handled wrench (any size will do as long as the handle is about a foot long)
Piece of 1 x 4 about 3' long

After getting the motor pointed the right way in it's nook, I looped the tie straps under it, and around the piece of 1 x 4, which was placed across the top of the fishwell opening. 2 straps were needed because one wasn't long enough.

After snugging the straps, I used the 9/16" wrench as a handle for a Spanish windlass. It was long enough that it could be held from unwinding by butting it up against the pumpout fitting. By winding gently, it was possible to get the motor height adjusted in tiny fractions of an inch, without getting a hernia.

Before starting the installation, the shear pin and thruster driveshaft slots had both been lined up with the mounting flange holes, which were a convenient reference point.

The motor slid into place without complaint. The "easy" (?) (stbd side) bolt was started by hand and turned in with just finger power. For micro-adjustments as the bolt went in, all that was needed was a slight deflection of the windlass.

The other bolt was a bit tougher. I was able to start it by hand coming in through the battery compartment (batteries are out, boat is getting a major rewire). However, it just wasn't possible for my 63 year old fingers to finish the job.

Working in tight spaces, allen wrenches can be a real pain, as it's hard to get them to index into the bolt, and there's only room to advance one flat per swing. This is where the 7/32" allen comes in. The bolts are 6mm, and 7/32 is about 5.5 MM - a sloppy fit. This loose fit made indexing the wrench into the allen bolt a breeze. Once the bolts were snug, I used the 6mm for final torqueing.

One item worthy of note: The "short" end of every allen wrench I measured got significantly "fatter" near the bend. The 6mm measured 5.96mm almost everywhere, but once I had cut it down, it measured almost 6.1mm. It dressed down just fine with a file.

Spent half the night figuring this out, and I couldn't be more pleased with the outcome. I'm a licensed motorcycle mechanic with over 40 years experience, and I have to say that this job rates very highly on my list called "Jobs I never want to do again". Bob Messmer, you were absolutely right!

I hope these ideas can perhaps be of benefit to the next lucky soul who is confronted with this challenge!

Thanks again to all who helped me with this one!

Bruce

 

[walldog]

Hi Bruce,

Great job, I know you are pleased that it is done. The tool below came with my boat it was in the with the manuals. Since you bought your used, it may not be in with your manuals. It is available from Ranger Tug I do believe. It is very handy if there is a next time for you.

 

[bruceandnoel]

Great looking tool - thanks for the info!
If I don't get one, I'll probably need it. If I get the tool, I probably won't need it. Pretty simple - I'll get one.
Thanks again.

Bruce