Set up ?

[Merc 2.5]

So for yall that run even or above ptp. Is it because light weight which is why ur able to keep your bow lift ? I loose my bow lift after a certain height , but it is a bass rig , but for bass boat I consider it on light side

[OnPad]

That's my experience also. I messed around with different setups low and high, on my bullet and ltv which run flatter high but still have plenty of lift designed into the hull. My champion I run 3+ inchs down.

[FORBESAUTO]

I’ve found surfacing helps stern lift from the blades entering the water from above the water line. I was hitting a wall at 77 running the bow high with conventional set ups, I feel mostly from aerodynamics and some of back end staying too wet on the old girl. When I started surfacing it, I was able to run neutral trim which increased straight ahead thrust. It allowed be to run the noise down more level and the stern up more which decreased wet surface. My hull pad is concaved in beginning then flattens out in rear to help trap air under it, which I think helps me pull it off. The change in set up plus power increases allowed me to get to mid 80’s so far. Pretty sure I couldn’t have gotten there flying the noise high. Plus driving boat is so much more fun and handles better at higher speeds.

[VkingMike]

I would imagine it also depends on the hull design. At a certain speed, the hull creates lift and keeps the bow up, at least on a hydrostream.

[David]

Weight, prop, power, and the aero/hydrodynamic lift of the hull. Boats are all different. I had a 115 on a 16' Baja and raising the motor from 3" below to 2" below did nothing for speed. My SS2000 is the opposite, engine height is critical. The Ally has a lot more power and a very different hull shape.

[FORBESAUTO]

Definitely will depend on hull design. My set up definitely not a typical set up to be surfaced, but once I done it, I love the attitude of the boat. I also want to add, a surfacing set up is all together different, you can’t just gradually raise till you get there, either the center line is going to on or above the surface or it ain’t. I originally played with a trophy. It would start loosing speed if I went any higher than 2 3/4 inches below pad. I figured it was no use going any higher and started trying many other props. Later on after I started surfacing with different props, I put the old trophy back on with motor 1/2 above pad just for protecting my good props just to find out the trophy would run and ran faster than ever with it surfacing. I has to do with lift being generated by the blades entering the water and not having to run positive trim I get maximum speed. Only drawback I’ve had, is with the weight of the boat and surfacing it, it tortures the lower unit. I’ve crushed a stock cast carrier, updated to billet. Then I’ve broken propshafts, just updated to sport master. But I love the set up so much, I’m gonna keep beefing up lowers to handle it

[OnPad]

What FORBESAUTO just said is straight up truth, and I had the same result with a trophy prop. There's a zone in between running high and low that doesn't work to well.

On the two boats I have surfacing. I run real high, right on the edge of losing water pressure with a nosecone, which seems to free up the boat and get rid of that, stuck to water feeling. Propeller choice determines boat attitude when running at these heights.

I'm not running extremely fast with my setups due to weight and hp, but am definitely running faster than I would be running subsurface. I also get better results with 4 blade large diameter props, they seem to have less vibration, more lift, and way better slip #'s, giving me my best top end speeds, and I have a tried a bunch of different props.