I tried searching the forums and did not find anything concrete about how a tunnel hull works with an SD. I want to run skinny, and DON'T have a MUD type application. Someone recommended Jet Drive, but they clog up and get Sh!t and grass in them pretty easily. I want to run some of the rivers where there are some shallow gravel riffles, etc.
My issues is that if you look at the profile of MM Boats/Motors, it appears that the drive still sticks down below the boat like 8-10 inches plus. Maybe these are trimmed down, and running it will be trimmed up a ton more?? That is fine in mud, but in gravel or small rocks, that is like a small outboard.
Anyone with experience on tunnel hulls with SD?

Waste of time don't put a mud motor on a tunnel.

Based on what?

Based on lots of other people trying it. Sd don't need a tunnel and don't run worth a shit on one. It disturbs the water to the prop.

mud motor will will run in 4-6 inches on plane n if u do hit they kick up unlike an outboard. Tunnel doesnt work well from what ive heard better w an outboard if ur gonna run a tunnel

Good input. Wonder if anyone on here runs the (TX) Brazos or Colorado rivers with their smooth bottom rig?
I have myself talked in to one, just trying to make sure.. before I plunk down a chunk o change and find out it wont do what I want it.

I run shallow rocky rivers wi mine and like it better than the jet i had. If ur getting 2 a shallow spot you can trim the props so there is less than half running in the water

Sd generally run better with half the prop in water. Where as outboards like the whole prop in the water. With a tunnel hull it makes more water up around the prop. Which SD do not like

Actually a tunnel would work very good in his case hard bottom the tunnel will allow him to be ably to get up on plane in very little water but it will be a few mph slower

So, when properly trimmed the motor runs at surface level. All you have is the skeg below the surface.

Wonder how much the tunnel hurts the SD? It is probably at top end when it is not getting clean water...?

Sounds like a power trim might be important to me, despite the potential for failures.

Def need trim

garret... u think the transom would need less angle for that being that the tunnel would be shooting water up to the prop?

prob I was told with a tunnel n sd was when it turns the prop exits the water from tunnel

My buddy had a gator trax tunnel hull with a 29 hyper drive and it ran pretty good, but he has since closed it in. He definitely hit less stumps with the tunnel, but it was a tad slower.

I think it has it's place if your not worried about losing a mph or two.

Would one type SD be than another to run on a tunnel?

A. Buddy of mine has a 20x42 weld built with a 36 pro-drive and it runs really good, I thought it wasn't gonna be worth a crap but man it'll run

A prodrive will probably be the one that will trim the highest, which seems to fit your application. But I dunno, this is an odd situation to start with, it's gonna be experimental for sure.

Leo's boat?

When you on Step running fast the water isn't going to be shooting up that much higher them it would without the tunnel. So with that being said you would set the motor about 4 inches higher in the transom if you have a 4" tunnel and it should be the same as Running it normal

I ran a couple SD motors on tunnel boats. From my experiments, the tunnel is 4 inches so normal outboard would be raised 4 inches. A SD with the longer reach, MB GTR GODEVIL, would need to be higher than 4 inches, being the tunnel stream rises the further back the prop is from boat. That is the reason a PD works better, it is similar to an outboard. Also would have to measure width of tunnel being SD props are a larger diameter. But it does work

Damn, don't we have some FE's on this thread!

I see the advantage of the tunnel with a surface drive when going straight, but when you turn, that long outdrive is going to be out of the raised water that the tunnel is making. So the prop would then be out of the water. I think the tunnel is more hassle than it is worth. I would just get a flat bottom. However, i have never had one, so take that for what it is worth...

This is the reason why so many of us have 2 or 3 boats. Cannot have one boat that does eveything.

All good input, guess what I really need to do is do a test drive on my river in question. That would help me figure out I it works! Course, if it doesn't they at not going to be happy.

I run the brazos through Waco (when my motor is up to par). It's a bitch, but if you know the river, and aren't a dumbass about it, it's doable. KNOW THE RIVER though. Six inches on plane in gravel is about as good as I can do. Shallower when I'm prepared for it. I'm running 1854 GT with gdsd. Miss my round chine though. Turning is cool in a lake; detrimental on the river. May I suggest you pony up to an airboat? For what we pay for our rigs, they can be had almost the same. And they make river issues irrelevant.