Oh OK. :bong:

Trim down for what? :grinser010:

haha yeah, not that kinda hydrofoil. That’s the problem, most people are familiar with just a v-hull, the stepped hulls are much different and most people have zero familiarity with them. And I think the stepped hull is more successful with larger boats, a 25’ boat I think is pushing it. My thought is that the front of the boat will have the most stability since that’s where it’s mainly ridding on, the outdrive is a sort pivot point for the boat. Trim tabs make no sense for what I’m trying to do and I’ve talked to other senza spectre owners about trim tabs. I just didn’t feel like getting into this conversation since I already did the research and I’m not trying to diagnose this problem, I just wanted to know if any stepped hull owners saw or thought a hydrofoil on the outdrive would help. The hydrofoil is kinda like a trim tab anyways but there’s no where to put the trim tabs that would benefit the boat, the step glides on an air pocket, the trim tabs would be literally in the air.

Yikes

Same problem on my Seafari 25. The brain trust doesn’t think the hydrofoil will do enough on the Seafari 25’ that’s a variable deadrise hull. Trim tabs have same issues as you noted above. One guy I know pulled a mold off hull to modify the tabs. I’m planning to install Volvo penta trim tab system that lowers a bar straight down from the transom to adjust ride. I’m toying with making an aluminum mounting plate with slots so I could raise and lower it to fine tune the final mounting point but I’m not sure it’s worth the effort.

For the cost of one, it's worth a try. Beyond that maybe a different style of prop, with less stern lift?

By “hydrofoil” I assume you’re referring to the fins that mount on the drives cavitation plate? What prop are you running now and how deep is the center or the propshaft below the bottom of the boat? If setup properly trimming up should alleviate the bow steering issue you’re describing, unless the prop is not deep enough, or contributing to the issue and lifting the stern because of wrong prop.

I had a step hull 22 DONZI with a 3 blade on it. Can not remember the make or pitch.

I ran one of those hydrofoils that bolt to the cav plate and it did help it get on plane faster. Didn't seem to affect the high speed handling of that hull.

As for TABS not helping because its a short step hull, that makes no sense at all unless you are mounting them ski high on the transom. Post a picture of your transom straight on from the back. What exactly is the boat doing?

If the boat is new, before you start trying things, does the dealer or manufacturer have any advice?

Props can make a huge difference..... On my boat, I was running a 23 mirage, I tried a cleaver and I though I was going to die it was so squirrely. With the mirage it was always predictable and very forgiving.

doubled the hp, raised the drive 2.5" and went to a 4 blade, it runs very flat and stable, if I try to trim it upit starts getting squirrley. I have a different 4 blade to try this summer with the bell cut off to decrease stern lift.

Too much stern lift can be a problem.....

If you guys don’t have or have never had a stepped hull, I’d appreciate it if you just let the guys with stepped hulls talk.
https://cimg0.ibsrv.net/gimg/www.off...7d226752a.jpeg
Not mine but it’s the same hull, rides on a pocket of air… do you see why I’ve said that trim tabs won’t work besides the fact that I talked to owners that said they didn’t help