Vector 115 hp prop set up

[Apollo]

I've run the boat and it seems you are right in that 10.5" seems like too large of a set back. Porpoising is a little more than ideal. The main problem is safety. it seems that at around 55 to 60 mph it seems to be running straight and true but can suddenly seem to fall off and veer sharply to left. stability is not good. Seems like maybe with the 10.5" set back jack plate the pad may be too far out of the water causingSthis lack of stability?? Also the weight of the motor being so far back makes it hard to carry rear passengers as water pours over the transom no matter how careful you are when you slow down and comes off plane.

We are going to take the present jack plate off of the boat. I am returning it for a full credit. For now i will temporarily mount the motor directly to the transom but with the knowledge of how it runs we will mounted it a little higher.

I am going to try to locate a 3 or 4 " set back jack plate. Do any jack plates of the this size have the motorized option or are they all manual units?

[Surface Scratcher]

Good lookin' Vector!

There a probably others but Bob's has a four inch hyd. plate.

http://www.bobsmachine.com/Products/jackplate_hydraulic.cfm

The sudden veering off is concerning. Tight steering and solid motor mounts may be in order. I'll bet it will be better when you move the pivot point forward by lessening the jack size. JMHO...a jack may not get you to go 65. You may about 150 hp.

[Apollo]

I truly appreciate the help.
When boat came out of the water last night after being in the water for 2 weeks I noticed the directional adjustable fin located above the prop gone (not there). I have ordered a new one will install and try to find best setting. I guess a 10" jack plate combined with no directional fin was the problem.
I'll check out bob's .

JB

[Yingchun]

The high five is a good ski prop with stump pulling low end. Choppers are a good all around prop as long as you don't have a lot of weight in the boat.

With a small performance boat set up is key.10" of setback is too much, 2-5 is optimal.

[silkeysak]

I truly appreciate the help.
When boat came out of the water last night after being in the water for 2 weeks I noticed the directional adjustable fin located above the prop gone (not there). I have ordered a new one will install and try to find best setting. I guess a 10" jack plate combined with no directional fin was the problem.
I'll check out bob's .

JB

You don't need that adjustable fin. It's generally out of the water anyway. Try a torque tab instead. It might help with your stability issues.

[Andyhydro]

I bought my dad a new stainless 4 blade for his 20ft Monterey IO. While I was trying different models at my local marina (helps being drinkin buddies with the owner) one of the 4 blades we tried lopped off the adjustable fin lol. Think thats what happened with your prop?

[jannypan]

With a small performance boat set up is key.10" of setback is too much, 2-5 is optimal. Dual cable steering, might also be a good investment. As is a water pressure gauge so you know how high you can run the motor.