Bow thruster problem

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Sailorsam101

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Left the marina on Saturday and all was well..until I needed a bit of thruster to get the bow out...two seconds of OK and then the rpm dropped and it started making a growling/growling noise.

I can't see anything in the tunnel and a bouncy day did not clear it either.

It's a lewmar with a stick to control it. I can't tell if the prop'is turning as the water is not disturbed at all when its on.

Any ideas folks?
 
Sailorsam101 said:
Left the marina on Saturday and all was well..until I needed a bit of thruster to get the bow out...two seconds of OK and then the rpm dropped and it started making a growling/growling noise.

I can't see anything in the tunnel and a bouncy day did not clear it either.

It's a lewmar with a stick to control it. I can't tell if the prop'is turning as the water is not disturbed at all when its on.

Any ideas folks?
Click to expand...

sheerpin gone easily replaced just unbolt the motor
 
Do I need to lift her out of the water to replace the pin...also I guess I need to find out what caused the pin to shear in the first place.

But if pin had gone would the motor not spin faster than normal?
 
Does it have an oil reservoir ? Under the fwd bunk .If so gravity pressurises the gearbox ,so direction of travel of fluid -oil - is out through the so called seals on the prop axle ?
When this runs dry -not topped up --then water is sucked in = rusty cogs = cease up .
Has the anode on the gearbox been replaced ? Help stop the case rusting at the bearing , protecting the gearbox .
Shear pin # does indeed cause motor to spin only -
Either a bag or weed or busted gearbox due to water ingess
 
From what I understand Lewmars do not have an oil reservoir and I'm not sure if mine even has anodes.

Out she comes I guess..!!
 
You don't need to lift the boat to change the sheer pin, but the ability to hang upside down in a confined space would be an advantage.
I had a pin go a couple of months ago and went through the same thought process as you, I was pleasantly surprised to find the sharpen is an easy fix.
 
Thanks for the replies but the bit i don't understand is should the motor spin at 1/3 speed with the pin broken...surely it should spin much faster as it's not connected to anything...and should it make the grinding noise it does?
 
The plastic prop failed on my QL bow thruster !
It sounded like a bag of washers.
The motor is mounted vertically in my case and i suspect a Lewmar is similarly arranged.
In my case there is a shear pin which is accessed from inside the boat. The motor unbolted and lifted off reveals the drive coupling and shear pin. Worth investigating. Even my limited spanner skills could have changed the shear pin , if it had failed.

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