Cavitation problems

[rentprop1]

Re: Cavitation problems

think i should try this before swapping lower units?

yes

 

[dabood]

Re: Cavitation problems

I would have to buy the props, however I can return them with no problem, they would guarantee or return.

RPM is around 5000, it should be closer to 5500 to 6000 correct? 2005 150 OptiMax That's where the lower pitch might come in with the 4 blades.

When I pull the whole shot it cavs. a little at first than gets up and goes with no problem, it does about 50 MPH. Clam water no problem.
I fish last week 1 to 2 ft. seas no problem. 3 people and all tackle and ice and (10 Dolphin).
Than I fished Sat. 2 to 4 ft. seas and had to stop and turn around. Cav. badly.

I can go to a lake in my area and swap props back and forth.

 

[Dhadley]

Re: Cavitation problems

I would have to buy the props, however I can return them with no problem, they would guarantee or return.

RPM is around 5000, it should be closer to 5500 to 6000 correct? 2005 150 OptiMax That's where the lower pitch might come in with the 4 blades.

When I pull the whole shot it cavs. a little at first than gets up and goes with no problem, it does about 50 MPH. Clam water no problem.
I fish last week 1 to 2 ft. seas no problem. 3 people and all tackle and ice and (10 Dolphin).
Than I fished Sat. 2 to 4 ft. seas and had to stop and turn around. Cav. badly.

I can go to a lake in my area and swap props back and forth.

You typically run / fish in 2 - 3 foot seas but want to test in a lake? Are you sure that's what you want to do?

 

[bob johnson]

Re: Cavitation problems

going down in pitch and over to a 4 blade from a 3 blade seems to be countering each other..and maybe leaving you pretty close to 5000 rpms still...

I dont know the optimax's rpm range, but over 5000 seems likely....

hopefully , you will have calm weather to test the props...you need to be in the right range for RPMs at WOT on plane, and trimming for the best speed...

to set up your motor prop combo...the cavitation should have less to do with the prop, and more to do with the relationship of the hull and waterline to the motor!!!

and at some point rough seas are going to mess up the performance of your boat!!!!

I have never been in your boat, but can you actually go WOT in 4 foot seas???

at some point you just got to slow down

bob

 

[dabood]

Re: Cavitation problems

Heck no, I have to go alot slower in rough seas, thats where the problem came in. 18 MPH plowing bow high.
I would not be there that day but the wind window was not there that day. I would have came back anyway. It did however bring this problem to my attention.
Its a catch 22 about testing, If its calm the only thing I have to go by would be the whole shot and rpm. Than I really wouldn't know the fix or not till It blew up a little while I was out.

 

[bob johnson]

Re: Cavitation problems

I only have an aluminum Mod V, 20.5' boat (22.5 with pods on the back) and since i use it mostly in the winter in new england 4 foot seas is not uncommon at all. and i dont call my prop catching air,in 4 foot seas.... Cavitation.... I call it LIFE!!!

thats the way it is!!!! doesnt seem to be a way to get around it other than leaving the rig on the trailer!! hja ha ha ha

when i had a 16 footer with an 18 hp on the back and got caught in 8-10 foot seas seemed the whole boat was falling through air when i broke over a wave.....didnt call that cavitation either !! ha ha ha

good luck

listen to whsii and Dhadley....

that offshore rigging has to be a secret unto itself

bob