2nd Shear Pin Snapped

[ethanbarnett]

Pin snapped after 30 days of limited use. Just replaced original that was 5 years old. Only quick 2-3 second bursts. This AM it just spun much like the previous break. Pin was not stressed. Thoughts?

 

[jagizzi]

Did you just have new bottom paint applied? You could check for growth in the tunnel as well.

 

[scross]

I’m curious as to what causes these shear pin failures. I get too much forward motion when using the thrusters can cause failures. I get that too fast a change in direction on the joystick can cause a failure. And that bottom paint can interfere with thruster prop spin and cause failure. Plus that getting any air in the thruster tunnel can cause a failure when water then hits the prop.
But most sheer pin failures don’t seem caused by these operator process and maintenance issues. What’s going on here?

 

[Cutwater28GG]

corrosion for lack of zinc maintenance?

unlucky floating material in the water?

 

[Red Raven]

If you go to the Imtra Side Power web site and order a replacement drive (shear) pin it is now a stainless steel pin. I think that answers the question. The brass pins just wear out over time. The stainless pins should last much longer. If you get something stuck in there without breaking the pin the fuse should blow.

On our trip to Alaska this year I had two stern theuster failures. The first was a wear out of the 2 year old brass shear pin, no sign of any foreign material in the water. It just failed. I replaced that one with a new (brass) pin. The second failure was a blown fuse only days later when I suspect I sucked up a very small chunk of ice while maneuvering for a picture in front of the North Sawyer Glacier. Since the brass pin was brand new I think it held until the fuse blew. Since I would much rather replace a fuse than a shear pin in the future I plan on buying stainless pins for my spare parts kit.

Curt

 

[NautiTug]

Yes last fall the first time out on my new to me C28 I broke the bow thruster pin. I ordered a replacement from side power and it was the stainless steel one. I had some hesitation using the stainless steel vs brass but since i ordered it directly form sidepower that alleviated most of my concern.

Last month I went to test my thrusters as I do every time leaving my mooring to pull to the dock and POP! Long story short an ugly eel decided the bow thruster tunnel would be a good space to rest. Fuse blew and did its job but no other damage to the thruster once I fished the dead eel out of the tunnel.

 

[Wee Venture]

Nautitug, I am curious whether the second time around you just blew a fuse and the stainless shear pin was still intact, or whether the shear pin broke again the second time. My question/concern is whether the stainless pin will break as it was designed to do with sudden stoppage of the prop. I just sheared a pin myself on our bow thruster and need to decide what to replace it with. SidePower’s website seems to show they sell brass pins for the 30 and 40 HP models and stainless pins for the 60. If they are supplying stainless pins for all of their thrusters now, I would be interested to know that.

John

 

[Eshwar]

then replace it...