Props slipping

[dog]

Hi, used the boat for the first time in a couple of weeks on Sunday and noticed under hard acceleration the props sounded like they were struggling for grip. Doesnt seem to be any bad fouling as she was lifted an cleaned about 6 weeks ago. I had this one or two times last season but didnt think too much of it. Could it be that the boat is slightly under propped? Twin Volvo D3 130s on SX single prop drives- engines reach 4000rpm WOT.

Any ideas anyone?

 

[DavidJ]

Does it sound or feel like the clutch going on your car. If so it's probable that the rubber connection between the prop and the inner sleeve has sheared. I believe these can be repaired.
David

 

[[2068]]

Possible, but unlikely that the rubber bit has failed on engines & drives so new.

How were the outdrives trimmed when this happened? It can help to have the drives trimmed right down before accelerating. Also with single props, it might be that hard acceleration with the single props is causing cavitation, where tiny bubbles are formed and collapse, which will eat away at your props, in which case the solution is to accelerate more progressively: or buy duoprop drives !!!

dv.

 

[brianrunyard]

Unlikely to have failed on both props at the same time

 

[DavidJ]

[ QUOTE ]
Unlikely to have failed on both props at the same time

[/ QUOTE ]
Thanks Brian you're right, millions to one chance of happening to both at the same time. I read the thread and it triggered a problem I had some years back (with a single engine)

 

[Hurricane]

Are you sure it isnt cavitating?
Get this all the time on RIBs when the trim isnt correct.
I just trim it out.
Just a thought.
I dont know if this sort of thing happens on the bigger boats.

 

[[2068]]

Isn't that what I said, or do I not exist ?
Times two.

dv.

 

[Hurricane]

Sorry - must have missed your post when reading thro'

 

[[2068]]

no probs, churlish to moan really, seeing as I did exactly the same to LakeSailor just the other week... /forums/images/graemlins/smile.gif

 

[duncan]

could be weed growth?

this will lead to the props 'slipping', is likely to affect both in a similar manner

amazingly it stays on!

just a possibility

 

[dog]

Thanks for all the ideas folks- I think that maybe it is a small amount of weed. Ive only ever had this problem after the boat has stood for several weeks- during the summer with regular use it doesnt seem to happen. I had duoprops on my last boat, and not once did they slip- perhaps its just an ism with single props.

 

[duncan]

DP's are more tolerant, and will chop up long strands a bit too, but will still suffer - my BIII certainly does when the weed stands growing on the props are over a few inches long......... /forums/images/graemlins/crazy.gif
as the boat is moored in shallow warm water with a good flow this can only take 4-6 weeks!