Stern Thruster on R-27

[knotflying]

Well the dreaded day arrived, not the shear pin, but functional issues. It won't work to port. With the help from Ray at Imtra in New Bedford, MA the issue is isolated and new relay ordered from Defender. The reason I am making this post is because a while back there was one made commenting that the rear thruster had to be sent in for service because it is a sealed unit. I can't find the old post, so here is a new one. My experience was a bit different. The sealed unit is actually made for thrusters that are in gas engine compartments and it is made to meet explosion proofing standards. Hence if service is required Imtra requires that they service it to ensure that it meets explosion proof standards when reassembled. Upon discussing this with Ray he conceded that because we are diesel powered a return to factory and subsequent testing of the seal was not necessary and returning the unit to Imtra not required. The next hurdle was that the wiring configuration in the stern unit is somewhat different than the bow unit so their published guide leaves one a bit lost for doing tests. Ray was able to walk me through it on the phone and it was determined that it was the relay, which is now on order from Defender.
And now the dreaded task of re-installation! Believe it or not I can still do headstands and work blind. Never knew I had a potential career in the circus.

 

[dclagett]

Thanks for post, it brings a question which is somewhat off topic but may be useful for others. When I purchased my RT25SC I noticed that the stern thruster prop had a slight play, it would move maybe a 1/16 to 1/8 inch at the tip of the prop. The bow thruster prop had no play. The prop is tight on the shaft so the shaft moves with the prop. When I pulled the boat last month, now both stern and bow thruster props have the same play. Is this normal or is there something that needs to be adressed? I have not found any reference to this on this site or the side power literature.

Thanks

 

[trailertrawlerkismet]

Mike:

If you don't find any circus helpers to help repair your stern thruster before the Florida Rendezvous then maybe there will be enough limber folks there to assist! Good luck and thanks for the post.

Jim F

 

[rpmerrill]

In my humble opinion, you are correct regarding the encapsulation of the thruster. It would be a big issue for gasoline fueled boats. Not a big deal for diesel. However, there is a pretty good chance for random water splashing around back there. When my thruster failed, I opened it up to complete the diagnosis. I ended up taking it to my dealer and he sent it out to get fixed. I closed the containment back up myself. The rubber gasket was in good shape. No big deal and I think it is fairly well sealed. It is just a hard plastic housing and has some flex to it. I wouldn't call it a hermetic seal, good down to 1 atmosphere. I thought about giving it a wrap with that sealer tape I keep seeing on TV infomercials, but didn't.

I just did some looking back in old posts and you participated in a post back in 2011 with a lot of detail about replacement. It helped me a lot last year. One idea that I had that helped me a lot was "installation studs". (Not referring to me and my neighbor who helped me. Long past the stud stage for both of us.)

By cutting the heads off some bolts i was able to install these studs into the two mounting holes. Then when lowering the thruster I could just slide it onto the studs and it would support itself (pretty much). I was able to spin a nut onto one of the studs and turn it finger tight. Then I took the other stud out and installed the proper bolt. Then I removed and replaced the second stud. Tightened them both up and had a beer.

The studs really made the re-install alignment problem go away. I was down in the hole doing the bolting and my helper lowered the thruster with a strap. Wrapped around the rear rail to steady it. Once we got set up, it only took about 15 minutes, not counting all the other stuff we had to put back together.

I wish you well. And Merry Christmas.

 

[DBBRanger]

Thanks for post, it brings a question which is somewhat off topic but may be useful for others. When I purchased my RT25SC I noticed that the stern thruster prop had a slight play, it would move maybe a 1/16 to 1/8 inch at the tip of the prop. The bow thruster prop had no play. The prop is tight on the shaft so the shaft moves with the prop. When I pulled the boat last month, now both stern and bow thruster props have the same play. Is this normal or is there something that needs to be adressed? I have not found any reference to this on this site or the side power literature.

Thanks

I got the dreaded NO-OP on my rear thruster. It turned out that the propeller was bad - the plastic spline in the hub of the prop was buggered up and only allowed a certain amount of torque to be applied to the prop. A new prop with 5 blades solved the problem. Of course most people talk about the motor and shear pin being the problem so I did that removal first only to find out they were not the problem. Had I looked at the prop first, I would have saved a lot of upside down time!

Yours may be on its way to needing a new prop.

 

[knotflying]

In my humble opinion, you are correct regarding the encapsulation of the thruster. It would be a big issue for gasoline fueled boats. Not a big deal for diesel. However, there is a pretty good chance for random water splashing around back there. When my thruster failed, I opened it up to complete the diagnosis. I ended up taking it to my dealer and he sent it out to get fixed. I closed the containment back up myself. The rubber gasket was in good shape. No big deal and I think it is fairly well sealed. It is just a hard plastic housing and has some flex to it. I wouldn't call it a hermetic seal, good down to 1 atmosphere. I thought about giving it a wrap with that sealer tape I keep seeing on TV infomercials, but didn't.

I just did some looking back in old posts and you participated in a post back in 2011 with a lot of detail about replacement. It helped me a lot last year. One idea that I had that helped me a lot was "installation studs". (Not referring to me and my neighbor who helped me. Long past the stud stage for both of us.)

By cutting the heads off some bolts i was able to install these studs into the two mounting holes. Then when lowering the thruster I could just slide it onto the studs and it would support itself (pretty much). I was able to spin a nut onto one of the studs and turn it finger tight. Then I took the other stud out and installed the proper bolt. Then I removed and replaced the second stud. Tightened them both up and had a beer.

The studs really made the re-install alignment problem go away. I was down in the hole doing the bolting and my helper lowered the thruster with a strap. Wrapped around the rear rail to steady it. Once we got set up, it only took about 15 minutes, not counting all the other stuff we had to put back together.

I wish you well. And Merry Christmas.

Thanks for the input - I was thinking about doing what you suggest or making up some small drift pins that I can just slide in and out.

 

[dclagett]

I got the dreaded NO-OP on my rear thruster. It turned out that the propeller was bad - the plastic spline in the hub of the prop was buggered up and only allowed a certain amount of torque to be applied to the prop. A new prop with 5 blades solved the problem. Of course most people talk about the motor and shear pin being the problem so I did that removal first only to find out they were not the problem. Had I looked at the prop first, I would have saved a lot of upside down time!

Yours may be on its way to needing a new prop.

Thanks, I will look at the props when I service the thrusters prior to spring launch.

 

[rpmerrill]

I think the bolts were 6mm, 1.25 pitch but that is just from memory. I believe I have it written down .... back at the boat.
It might even be posted here somewhere?

But since you have your thruster removed, just go to Lowes and get two bolts that match the existing bolts. Then cut the heads off.
They don't need to be stainless because they are only temporary.

 

[rpmerrill]

Looked it up.

8mm, 1.25 pitch bolts