NEED Stern LIFT Prop Suggestions

[vroom ZOOM]

that motor looks way too short for your hull. is the boat new to you?

Well, I just got it this spring, didn't touch the motor height since.

 

[vroom ZOOM]

Height is set for pretty high performance at that height. Wouldn’t say it is wrong shaft length. It’s a performance hull guys. Has a flat pad on it.

yes, this boat has a pad. First it gets out on plane, then if I manage to get past the porpoise then it gets out even more on the pad.

 

[vroom ZOOM]

Agree on the pad and height could be part of the performance desired. Problem I have is recalling the rule of thumb from the big guns on here, especially a guy from Coral Gables, Fl. I think, with a 300 Johnson on a Donzi I think among other things: 1"up from even per 6 inches of setback.

Using the diameter of the LU gearbox as a quasi reference, if he trimmed out like he was running on that pad just prior to blowing out, he might get a foot of separation indicating a 2" rise in engine height. Looks a lot more like a short shaft on a long shaft transom, or long shaft on a 25" transom. Limited knowledge, but I know of no BBs with a 25" transom mounting position......but like I said....limited knowledge.

There are no 15" suzi's. I'm pretty sure this is a 20"

 

[vroom ZOOM]

May be right. Hard to tell with the angles engine is at in pictures, but I think 1” up would be a sensible set up for your average speed boat. 2-3” would be high performance and with a pad set up.
Hard to say...but I’m not sure it’s as much as 5” there to suggest it may be a short shaft. Would sure be a rare find to get a short shaft motor like that on a boat. Probably more likely the engine is just high on the transom. Need more pics perhaps ? All the best.

i'll get more pics as soon as I get it parked out of the bush in a different spot

 

[vroom ZOOM]

From what I can gather to this point, it seems like when I have more weight in the boat, the pad keeps sinking and the porpoise starts. i have to figure out how to get that pad up. as I mentioned before if I can get past the porpoise it is going fast enough to be fully out on the pad, then I can trim out A LOT. I am getting a whale tail first, it should allow me to speed up, and then when on the pad it shouldn't be much drag.

 

[Texasmark]

Speed is what forces the boat out of the water and on plane and finally on the pad. The boat weighs X pounds. The water pressure against the hull has to exert essentially that number of pounds in "pounds force"....an active dynamic for you to get on the pad. If you can't get enough speed to do that it will not perform as designed. Otherwise it will act like a "deep V" hull which rides "IN" the water, not "ON" it and the required propulsion for a given speed is high as compared to other hulls of the sort....displacement hulls (Ships, tugs, barges, sailboats etc.) exempt from this comment.

 

[QBhoy]

Speed is what forces the boat out of the water and on plane and finally on the pad. The boat weighs X pounds. The water pressure against the hull has to exert essentially that number of pounds in "pounds force"....an active dynamic for you to get on the pad. If you can't get enough speed to do that it will not perform as designed. Otherwise it will act like a "deep V" hull which rides "IN" the water, not "ON" it and the required propulsion for a given speed is high as compared to other hulls of the sort....displacement hulls (Ships, tugs, barges, sailboats etc.) exempt from this comment.

Mine on the pad...to demonstrate this exact point. Spot on TM

 

[Texasmark]

Mine on the pad...to demonstrate this exact point. Spot on TM

Lookin good! Wink!

 

[QBhoy]

Lookin good! Wink!

Some machine texasmark. Goes so well for her unusually heavy hull. 1 of 15 ever made. Lucky to have her.