prop grip problem

IBWET · 17 April 2007, 21:15

I think this is a goodun for someone knowledgeable, my rib when travelling on the plane (speed not critical,but say 25 knts) has a problem I think may be prop related but I'm not sure, so I'll ask the question;

If I trim the boat up after setting the throttle,you can see the wash/wave moving towards the rear of the boat,as it should so the trim works,however if an adult move forward from the rear of the boat to midships the bow lowers back down, wash moving forward again you can feel the prop almost giving up.

obviously redistributing the weight will have an affect but this is pronounced it's as if the prop lets go too easily . Is this normal ? After a bit of googling I think a four blade might solve the problem but I'm guessing anyone experienced this?

Biggles · 17 April 2007, 21:20

Iain,

Are you still running the original prop ?

IBWET · 17 April 2007, 21:24

Hi Nick,

I've ended up after going through 21" 23" and now have a 3 x 14 3/4 x 25" however it is the suz prop.

Quote:

Originally Posted by Biggles

Iain,

Are you still running the original prop ?

Bigmuz7 · 17 April 2007, 21:37

Quote:

Originally Posted by IBWET

I think this is a goodun for someone knowledgeable, my rib when travelling on the plane (speed not critical,but say 25 knts) has a problem I think may be prop related but I'm not sure, so I'll ask the question;

If I trim the boat up after setting the throttle,you can see the wash/wave moving towards the rear of the boat,as it should so the trim works,however if an adult move forward from the rear of the boat to midships the bow lowers back down, wash moving forward again you can feel the prop almost giving up.

obviously redistributing the weight will have an affect but this is pronounced it's as if the prop lets go too easily . Is this normal ? After a bit of googling I think a four blade might solve the problem but I'm guessing anyone experienced this?

Do you mean the prop cavitates ? Its not unusual for the weight distribution to be sensitive underway, but trim should be able to account for that, unless you cant get enough that is, which means your transom angle /vs motor might need more range, sortable by a wedge

Biggles · 17 April 2007, 21:49

Iain,

I had problems with my original one. I got one from Ribshop and it solved all my problems.

Talk to Kieron at RIBSHOP and explain your problem. he has done extensive testing on Suzi 140s and knows his stuff.

http://www.rib-shop.com/contact.asp

regards Nick.

Biggles · 17 April 2007, 21:50

Iain,

I think there is a problem with the Suzi gearcase. I think a new one has recently been released.

IBWET · 17 April 2007, 22:51

That's interesting, where does that info come from? I think the engine is still a little to new for any real knowledge base to have developed yet, but I'll give Ribshop a call.

Cheers nick.

Iain

Quote:

Originally Posted by Biggles

Iain,

I think there is a problem with the Suzi gearcase. I think a new one has recently been released.

Biggles · 18 April 2007, 13:46

Quote:

Originally Posted by Biggles

Iain,

I think there is a problem with the Suzi gear case. I think a new one has recently been released.

Iain,

I read somewhere on the US part of RIBNET that Suzuki had very recently redesigned a new gearcase because the shape was causing some problems. He had one on order for $400. Personally I'll put up with the problem at that price as the prop I got from Kieron solved all my problems. Well it did until my mate went across a mud bank and took some paint off it and scuffed the leading edge.

martini · 18 April 2007, 16:24

Where is the cavitation plate in relation to the bottom of your keel? Outboard may just be sat too high on the transom.

floater · 18 April 2007, 21:56

hi

My new Rib does excactly the same, and i have just had the engine lowered as the manual states that the cavitation plate should be level or below the bottom of the hull, it was an inch higher , will be picking the boat up on saturday will let you know

Andy

IBWET · 20 April 2007, 10:59

Thanks, Andy.

Quote:

Originally Posted by floater

hi

My new Rib does excactly the same, and i have just had the engine lowered as the manual states that the cavitation plate should be level or below the bottom of the hull, it was an inch higher , will be picking the boat up on saturday will let you know

Andy

codprawn · 20 April 2007, 13:11

They put engines higher to give better top speeds as that is what sells boats. Of course under load - in tight turns or rough weather you need the engine in deeper - that's what a transom jack is for!!!

http://www.boatownersworld.com/CMC/pl65_power.htm

With the strength of the £ versus the $ at the moment and the fact most jacks are made in the USA now is an excellent time to buy one!!!

£350 for a hydraulic one ain't bad at all......

IBWET · 20 April 2007, 23:08

Probably a sound theory cod, however the RIB is only 5.85 long,with a 220kg engine, adding more weight on the transom is not an option. I'll see how the cav plate relates the hull, but a 4 blader is my only option I think.

Quote:

Originally Posted by codprawn

They put engines higher to give better top speeds as that is what sells boats. Of course under load - in tight turns or rough weather you need the engine in deeper - that's what a transom jack is for!!!

http://www.boatownersworld.com/CMC/pl65_power.htm

With the strength of the £ versus the $ at the moment and the fact most jacks are made in the USA now is an excellent time to buy one!!!

£350 for a hydraulic one ain't bad at all......

codprawn · 20 April 2007, 23:15

Quote:

Originally Posted by IBWET

Probably a sound theory cod, however the RIB is only 5.85 long,with a 220kg engine, adding more weight on the transom is not an option. I'll see how the cav plate relates the hull, but a 4 blader is my only option I think.

Ahh yes - I was on about bigger boats.

pathalla · 21 April 2007, 02:40

Quote:

Originally Posted by codprawn

Ahh yes - I was on about bigger boats.

Bigger boats?? C'mon Cod, you might as well be piloting a bus out of the harbor.....