Bow Thruster Stops Working

[PhilPB]

Today I was painfully reminded the need for controlling your boat while backing into slip, in the wind with an inoperable bow thruster.
Today we took the boat out. The thruster worked fine for me to maneuver the bow so the wife could easily remove the bow lines when leaving the slip, then it stopped working. The motor would run but either the prop is missing, or something else. No cracks or thinks when it did work. Time to come back to the slip and I quickly realized how dependent I was on the thruster. Took quite a while getting the boat backed into the slip (single screw) and now have a damaged bimini bow for the cockpit bimini.
The thruster is just over a year old, professionally installed. Bottom is cleaned regularly and the diver is going to dive and investigate the thruster in a couple days.
Today was a hardly gentle reminder that I need to have complete control of the boat without the use of a thruster. Needless to say , it was a quiet drive home afterwards.

[mvweebles]

Maybe the sheer pin?

https://www.youtube.com/watch?v=mhk_0IMEs9s

Peter

[Pete Meisinger]

Sounds like a shear pin. It can be replaced from inside the boat in the water, no need to haul out. I always have a spare taped near the thruster motor.

pete

[Comodave]

What bow thruster do you have? Agree it could be the shear pin, if it has one. Or could be a fuse or breaker.

[mvweebles]

Originally Posted by Comodave

What bow thruster do you have? Agree it could be the shear pin, if it has one. Or could be a fuse or breaker.

Motor runs but no thrust.

I think there are sheer pins on my thruster props - the bonehead team forgot to install them so motor ran but no thrust. . I don't know much about these things. New to me.

[Comodave]

Originally Posted by mvweebles

Motor runs but no thrust.

I think there are sheer pins on my thruster props - the bonehead team forgot to install them so motor ran but no thrust. . I don't know much about these things. New to me.

I missed the motor runs part…

[mvweebles]

Originally Posted by Comodave

I missed the motor runs part…

Comodave - you seem to know a lot about a lot. Do thrusters typically put sheer pins on the props like OBs do? When I read the OPs post, I googled sheer pin and was somewhat surprised where it is on side power thrusters. I don't recall my brand, but it occurs to me that I need to get a couple of spare sheer pins. As mentioned in my previous post, there are transverse pins on the prop shaft, but I don't know if they are sheer pins or not. Thoughts? How are these things protected?

Thanks in advance

Peter

UPDATE - I have a SidePower thruster. Guess I better get to work on learning more about it and some spares.....

[PhilPB]

Originally Posted by Comodave

What bow thruster do you have? Agree it could be the shear pin, if it has one. Or could be a fuse or breaker.

Side power / Sleipner SE60/185 12v
Fuses and breakers are fine.

[Comodave]

Originally Posted by mvweebles

Comodave - you seem to know a lot about a lot. Do thrusters typically put sheer pins on the props like OBs do? When I read the OPs post, I googled sheer pin and was somewhat surprised where it is on side power thrusters. I don't recall my brand, but it occurs to me that I need to get a couple of spare sheer pins. As mentioned in my previous post, there are transverse pins on the prop shaft, but I don't know if they are sheer pins or not. Thoughts? How are these things protected?

Thanks in advance

Peter

UPDATE - I have a SidePower thruster. Guess I better get to work on learning more about it and some spares.....

Sidepower actually calls them drive pins. I believe they are just in back of the props.

[PhilPB]

Originally Posted by Comodave

Sidepower actually calls them drive pins. I believe they are just in back of the props.

I'm still researching. It appears that the shesr pin is within the motor. I was hoping there was one on the prop.

[chanprr]

The shear pin is on the motor shaft (see #8 in the diagram). The motor has to be dismounted to replace the shear pin.

[C lectric]

The shear pins do fail.
A dockbuddy had a thruster, bow, and about once a year it had to be replaced.

[Jeff F]

Originally Posted by Comodave

Sidepower actually calls them drive pins. I believe they are just in back of the props.

Are they really meant to shear?

I think on my Vetus bow thruster the prop would disintegrate before the drive pin.

[Comodave]

I had a Sidepower stern thruster that I installed on our last boat. Never had the shear pin or drive pin shear. Don’t actually know if that model had one or not.

[Bacchus]

Originally Posted by chanprr

The shear pin is on the motor shaft (see #8 in the diagram). The motor has to be dismounted to replace the shear pin.

I believe the PROP has to be removed to clean, lube, replace the drive pin.
Boat needs to be short hauled or work done by a diver.
No need to touch motor on mine or the ones shown in the diagrams.

[PhilPB]

Originally Posted by Bacchus

I believe the PROP has to be removed to clean, lube, replace the drive pin.
Boat needs to be short hauled or work done by a diver.
No need to touch motor on mine or the ones shown in the diagrams.

Don, What make and model of thruster do you have?

[PhilPB]

If it requires partial removal of the motor hopefully it can be done in the water without having water intrusion.

[Bmarler]

There are usually two different pins on a thruster, (depending on model) the drive pin behind the prop is usually a more robust one and the shear pin under the motor is designed to fail if the prop draws in a piece of rope or similar. The clearance in the tunnel is usually really tight and you don’t want the thruster grinding a hole in the tunnel.
The pin under the motor is designed to be replaced with the boat in the water. There is no water ingress as it’s a sealed gear case.

[mvweebles]

Originally Posted by Bmarler

There are usually two different pins on a thruster, (depending on model) the drive pin behind the prop is usually a more robust one and the shear pin under the motor is designed to fail if the prop draws in a piece of rope or similar. The clearance in the tunnel is usually really tight and you don’t want the thruster grinding a hole in the tunnel.
The pin under the motor is designed to be replaced with the boat in the water. There is no water ingress as it’s a sealed gear case.

Well, I'm confused about my 3-year old SidePower SE80 (6hp) bow thruster. The video I posted up-thread shows a sheer pin on the motor which is replaceable from inside the boat. But the exploded diagram doesn't really show anything - except two different Woodruff keys. The Troubleshooting section makes no mention (see screenshot). Any comments from Sidepower owners?

Full Install Manual HERE

Peter

[Hippocampus]

Look carefully at the tunnel. Know you probably know this but others may not.

Went to top off before leaving Skull creek at Hilton head. Strong current there. Went to fuel dock then turned around to be going into the current docking. Before we leave it’s our habit to check the transmission and thrusters before the first line is thrown off. Everything was fine. But as we made the turn into the fuel dock the bow thruster failed.

Had the boat short hauled in Marsh Harbor. Found out the upper unit rotated a wee bit causing the prop blades to just scrap the tunnel a wee bit in one area. However over time this was enough to burn out the motor. Was cost effective to remove the whole thing and replace with new even though it meant new controls.

Without a bow thruster wasn’t sanguine about doing the ICW so after getting fuel had to dock again. That one was more difficult as was the one in Marsh Harbor. Still no harm no foul. Definitely worthwhile to practice without thrusters. Was fortunate all were side ties although quite tight.