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Amel Super Maramu 2000

Bow Thruster - double propeller loss

The wind was 16 kt, I proceed out of the tight slip, I reverse 10 meter then I heard I lost the bow thruster propeller (higher pitch).

I dove to confirm the prop was gone. No problem, I have spares.
Strange enough the plastic hub was still resting on the (tufnol) shaft.

Out of my 5 bow thruster propeller:
The 3 whites had the hubs stuck.
One black had 8 holes
so 1 useable left (lesson to learn)
First bad news, the plastic hub was too large to fit on the black prop. I spent 3 hours sanding by hand the prop to make it fit.

Dove to put spare propeller, it felt wobbly. After 4 burst of 3 second each I lost the bow thruster propeller again.

I found both propellers, the nylon bolts still on. which makes me suspect the hub failed.
Closed inspection showed the normally round holes around the pin retaining the propeller were now oval.
Also the nylon bolt pull right through the thread
Is this from wear? Something else?

Is the spare propeller with 8 hole propeller still useable? Seems a little weak.

Then started the Bow Thruster removal in the water following the:
http://nikimat.com/bow_thruster_overhaul.html

I had to use a prop or bearing puller in order to remove the plastic hub of the white propeller.
Not normal considering you should be able to change these propeller in the water or I am mistaking?

Somehow these propellers are made of Aluminum, while the other 3 in composite. Is this common?

Next bad news: the removed hub is too thick for the tulfnol shaft.
The pin will not fit/slide in.
More bad news, it is also too thick for my spare tulfnol shaft.
Not to mention the spare tufnol shaft does not the same dimension as the one I have.

Out of my 5 bow thruster propeller:
The 3 whites had the hubs stuck.
One black had 8 holes
so 1 useable left
note: the blue was later found.

First bad news, the plastic hub was too large to fit on the black prop.
I spent 3 hours sanding by hand the prop to make it fit.
 Amel Super Maramu 2000 Bow Thruster lost propeller

 

I found both propellers, the nylon bolts still on. which makes me suspect the hub failed.
 Amel Super Maramu 2000 Bow Thruster lost propeller

 

 
 Amel Super Maramu 2000 Bow Thruster lost propeller

 

Closed inspection showed the normally round holes around the pin retaining the propeller were now oval.
Also the nylon bolt pull right through the thread
Is this from wear? Something else?
 Amel Super Maramu 2000 Bow Thruster lost propeller

 

 
 Amel Super Maramu 2000 Bow Thruster lost propeller

 

Is the spare propeller with 8 hole propeller still useable? Seems a little weak.
 Amel Super Maramu 2000 Bow Thruster lost propeller

 

I had to use a prop or bearing puller in order to remove the plastic hub of the white propeller.
Not normal considering you should be able to change these propeller in the water or I am mistaking?
 Amel Super Maramu 2000 Bow Thruster lost propeller

 

 
 Amel Super Maramu 2000 Bow Thruster lost propeller

 


 Amel Super Maramu 2000 Bow Thruster lost propeller

 

Somehow these propellers are made of Aluminum, while the other 3 in composite. Is this common?
 Amel Super Maramu 2000 Bow Thruster lost propeller

 

Next bad news: the removed hub is too thick for the tulfnol shaft.
The pin will not fit/slide in.
 Amel Super Maramu 2000 Bow Thruster lost propeller

 

More bad news, it is also too thick for my spare tulfnol shaft.
 Amel Super Maramu 2000 Bow Thruster lost propeller

 

Not to mention the spare tufnol shaft does not the same dimension as the one I have.
 Amel Super Maramu 2000 Bow Thruster lost propeller