Jack plate and bow lift

[FurFlyin]

I decided to start another thread instead of continuing the one about my motor problems. Those are fixed. Now I've got to get my jack plate tuned in. I need more bow lift. I don't know if a jack plate will help, or hurt that, but in my mind it should help.

I started out with the center of the prop 4 1/2 inches below the level line of the keel. I didn't get the bow lift that I needed. The boat performed well. It handled better than it did prior to the jack plate. The top speed did not change one bit. The porpoising at WOT did not improve, nor did it get any worse. I made the executive decision that dropping the motor would help lift the bow and I lowered the motor an inch. It had no effect. None. Boat performed exactly the same as it did prior to lowering the motor.

I did pick up about 100 RPM's with the jack plate. Now I'm running 5500 RPM's on a 98 115 Yamaha V4 2 stroke. I figure that's pretty dang close to optimum. Dropping to a 19 pitch prop should put me at around 5700 and that was recommended to me, but I don't know if that's actually what I need to do or not.

Would a 4 blade prop give me more bow lift? Seems to me that it would, but that's really just a guess on my part. What negatives would I experience with a 4 blade prop and would I need to drop pitch if I go with 4 blades?

EDIT: Forgot to mention, it's a manual 6" Vance jack plate.

Thanks for any advice.

[Rip Bass]

The problem with bow lift on a smaller engine like that is lack of blade area on the smaller diameter props for that engine. So a four blade should give you more bow lift. You could try a larger diameter three blade too. Mercury makes one for their smaller engines but I can’t recall the name of it right now. You will still need to be around 4” under to get a good bite with the smaller props.I would stay with a 19”. If I can remember that prop’s name I will post back.

[HokieV20]

Having you prop blueprinted will also help. The added cupping on the blades helps alot.

[K-DAWG]

Yes a jack plate will help. It changes the leverage the motor has over the boat by moving the pivot point back farther on the hull. That in turn makes the bow lighter easier for the motor/prop combo to tote the bow. No down side to adding a jack plate as long as the boats transom is in good shape and can handle it.

[bluebonnet2]

good morning,

Cbaily foil, hole shot on my skeeter zx200, about 30 ft. he is on here and facebook......plane level at about 20 mph.....just saying

good luck,
PURA VIDA,
bluebonnet2

[FurFlyin]

Thanks for the replies. bluebonnet, I'm gonna need a little more details on what your talking about, or at least an interpreter. LOL If you're talking about a hole shot plate, I already have a custom one for it. It's a FurFlyin Customs hole shot plate. I would have made my own jack plate but I don't keep the angle on hand to make it from and by the time I ordered a whole stick of it I wouldn't have saved enough money to cover the costs.

[hatcreek]

...I'm gonna need a little more details on what your talking about, or at least an interpreter...

Here ya go...

http://www.bbcboards.net/member.php?u=74090

[FurFlyin]

For those of you who have followed my saga, MY BOAT FINALLY RUNS GREAT!

I am a member of an AL hunting forum and the members there recommended talking with William Bush at Huntsville Prop Sales and Repairs. I called him today asking about a 4 blade prop. He then asked me about 20 questions about my boat and set up. After telling him everything he wanted to know, he told me he wanted to see the prop that I was running. (Laser II) I told him I had bought it online from a prop shop in TX around 2 months ago and it was in great shape. He said he still wanted to look at it and check it, before he made any recommendations about what I needed to do. I asked him if he could look at it today and if so I'd head that way with it. He said he could, so I left work and made the 45 minute drive.

When he looked at it, he said "it looks okay, but I'm going to check it." I walked over to his bench with him so I could watch what he was doing. He put it on a spindle and put a gauge on it to check the pitch. Turns out, one of the blades was nowhere near correct. The back edge of the blade was about 3/8" from where it should be. He put it on his block for that prop and beat on it a few minutes. Got up and polished it up and told me he wanted me to try it before we did anything else. I brought it back, put it on the boat and headed to the lake. The porpoising issue is 100% gone. The boat jumps out of the hole and the bow stays up off the water like it should. In one 2 hour fishing trip I got to run my boat on all types of water from flat to white caps. It performed fantastically in every condition. I am so happy that this mess is finally behind me!

[larryhyco]

Yes a jack plate will help. It changes the leverage the motor has over the boat by moving the pivot point back farther on the hull. That in turn makes the bow lighter easier for the motor/prop combo to tote the bow. No down side to adding a jack plate as long as the boats transom is in good shape and can handle it.

Excellent answer !!!!

[bulldog44]

Great news...
Is this with or without your jackeplate?

[fastman151]

Glad to hear your problem is solved!

[FurFlyin]

Great news...
Is this with or without your jackeplate?

With the jackplate.

[FurFlyin]

Glad to hear your problem is solved!

Me too, thanks!

[bulldog44]

On that Laser II prop...was it a new out of the box prop or a used prop?
Following your lead, I sent off my Stiletto 15 to have Mark repair it and add some cup. I have a new Turbo I 17 that I will be revisiting this weekend, going to play with both to see what works best. Do you feel the 6" Vance made a difference, or was it totally the prop? And when you say stopped completely, is that no matter how high you trim? What distance did you finally settle on PTP with your jack plate?
I'm been reading threads, disgesting all the fixes, and going one step at a time working to improve my boats performance. I have not ordered a jackplate yet, but I will after testing my two props.

[FurFlyin]

I can't say for sure if the jack plate helped the porpoising issue or not. The jack plate did help the ride and handling of the boat in rough water.

The Laser II prop was bought from a prop shop in TX and sold to me as being checked and having a new bushing in it. It did have a new bushing in it, but it was nowhere close to right.

I'm not sure what my pad to prop measurement is and I'm not sure I'm finished adjusting my jack plate. The porpoising is fixed but I'd still like more bow lift. After talking to the prop guy again he recommended a Michigan Wheel Apollo prop. I called MI Wheel and spoke to them. They recommended a Ballistic prop. I ordered one from a dealer in Michigan or Minnesota (can't remember which) because they offer a prop swap deal where if my prop doesn't perform well, I can swap it for another one and I'm just out the shipping to get it back to them.

When I finally get every little thing dialed in perfectly, I'll post the info or PM you. If you haven't heard anything in 2-3 weeks, send me a PM.