2014 Cutwater Stern Thruster Broken Sacrificial Pin

[mariemuma]

Has anyone said more than a few cuss words while replacing their stern thruster pin?? The two bolts that must be removed do not have enough clearance to get the supplied tool sunk into the hex-head screw. The shape of the motor has created a bit of a "flange" that cuts off the clearance. We had to break off an Allen wrench so that it was short enough to be able to seat properly. Obviously a non-ratcheting tool for this application is absolutely ridiculous!! I find it hard to believe that we got the motor off and installed the new pin. Hubby has gone to look for different screws for the motor. We still have to reinstall the motor!!

Any feedback would be appreciated. Marie

 

[tugnnaweigh]

This is discussed at length in the "Thruster troubleshooting, dumb question" thread now trending. In my input, I mention holding the thruster at the correct elevation with a 2 X 4 underneath it. If I had to do it again, I'd build more of a cradle for it which you could do as you currently have it out. If your hubby's thought is to change the fasteners to hex head bolts that could well solve the access problem. Take note of the folks that modified fasteners so they became threaded studs permanently attached to the transom piece. Good luck, rich

 

[stwendl]

The best way to prevent shear pin damage is to convert to proportional thruster control. The full power when turning on the motors puts quite a bit of stress on the hardware. Even a ramp up controller would be helpful already

 

[Osprey]

I recall thar some time back a poster suggested that shortening the hex bit will provide the required clearance. Currently following the thread mentioned above switching to studs prior to reinstalling seems a good idea.

 

[tlkenyon]

On Monday, I am going to replace the shear pin (aft thruster) and replace the screws with studs.

Question....is there enough clearance to rotate a conventional hex the nut on the stud? It is impossible to tell by just looking. Is a very small clearance possibly the reason for the female hex fastener?

TK

P.S. - I will do a through job of documentation and present the results....and "challenges".

 

[tugnnaweigh]

You are right the clearance is tight and keep in mind it changes as the install progresses. I cut down fasteners to go the threaded stud route but gave it a try with the stock fasteners when I noticed they seemed happy to remain in their positions on the thruster body while positioning it. My neighbor helped me on the thruster side as the wife wiggled the propeller to help the shear pin enter the yoke. Overall, I'd say we got lucky at several spots; realize folks have posted regarding boat yards flat refusing this task!

If you go the stud route, keep in mind if the stud is too long it will contact the body of the thruster prior to the nut tightening the thruster to the other piece. I also kept in mind the fasteners are not a snug fit in the thruster, the point being the thruster could have a tendency to wobble on the studs losing the yoke to sear pin interface; perhaps folks that have gone the stud way can weigh in on this aspect.

In setting up for the stud method there were some bedeviling subtitles; I could tell how far the original fasteners had threaded into the hole but couldn't figure out what the stud would do when I threaded it in. Is the tapped hole a bottoming tapped hole? A through tapped hole? Would the stud resume turning when I screwed a nut down on it? I like using nylock nuts and felt pretty sure if it could turn it would turn when the nylock part of the nut hit.

So a poster put up about using LockTight and I decided I'd do that and cut the stud length to having 3 to 3.5 threads in the transom part which I could tell was the thread depth of the original fasteners and made sure it had the same amount of thread sticking out the end the nut would fasten to. While it's acknowledged a nut half threaded is rated at full strength, my personal preference is to end up with a bit of the stud sticking out so that's the length I shot for.

Also, keep in mind when you use LockTight, even LockTight blue instead of LockTight red you're pretty much through, you're not going to get back apart what you've used it on without heat and you won't find me waving a blue flame around in a fiberglass enclosed area that I cant even see into when my arm is down there!

In hindsight, I'd build a nice little cradle for the thruster so it might stay in place after it's shoved against the transom and all you have to do is rotate it to get the holes to line up with the fasteners. I also very much agree with your thought of using hex head bolts as that solves not only the clearance problem but also a problem I ran into; that of the initial finger turning of the bolt, much easier with hex head than the smooth round outside of an Allen head bolt!

Also, I had to finger tighten the Allen head bolt sufficiently so the wrench would "ratchet" on the back stroke and not just turn the bolt both ways. And of the two wrenches I ended up with, one was much much more resistant to ratcheting than the other one. Hex bolts eliminate this worry completely, of course.

So I take a little pride in doing something boat yards won't do and I'm a little sad because now that I"m good at it I'll never do it again! Whew, just the telling of the tale gets me going, I gotta go lie down. Hope this helps, rich

 

[tlkenyon]

Rich,

Your experience and insight are great, and I thank you very much. We are gonna take it apart and see where it takes us...studs or original Allen-head bolts. Should be interesting.....

TK

 

[mariemuma]

The job is done!! The hex head bolt that Craig bought did not work at all for the port-side more difficult bolt as there was not enough room to use a tightening tool. I went back to the original Allen-head bolt. The small ratcheting tool that we got from Cutwater came in handy, but with a modification. We actually cut the bit of this tool down to make it clear the space and accomplish a proper seat. Without cutting down the bit, the bit could not seat directly in. I do not know how you were able to initially loosen this more difficult bolt as I could not even get the bit in enough to even loosen it: I could not get any sort of "bite" necessary to even loosen this Allen-head bolt. With the altered ratcheting tool, I was able to get it going!! Yes, the tool had to be taped such that the bit would not fall out. We have ordered another tool and we will similarly alter that one. Our plan is to have one that will turn left and one for tightening. We have a friend who will spot weld each of these so that they will be perfect for future occurrences.
To make this an even easier job, we will devise some sort of cradle that will hold the thruster motor at the level that is necessary.
It will be interesting to see how this goes on the next time we break the pin. The first "pin replacement" was done by Ivan from the Factory. We certainly should have taken video footage and been so much more involved, even putting our hands on the supplied ratcheting wrench. This time, we did it ALL BY OURSELVES. Next time, it should go so much more quickly and easily.
Now we are off for a 5 day cruise to South Puget Sound, trailering our Cutwater down to a launch ramp in the area. After that we plan to spend most of the winter in the Sea of Cortez.