Prop or Jet for this Tunnel

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jtf

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Need some 1st hand advise please. I traveled to look over the Alweld Marsh boats. Liked what I saw. However, the factory says they make only the "performance tunnel" in that series. It's only 3" deep and nearly flat.

Intended to use a prop (like a former boat was set up), and the factory insists it's their best design for a prop. I don't see how it can help compared with Alumacraft or SeaArk designs.

Can someone that uses their tunnel give me some pointers? Btw, their Mud series uses a small 4" prop tunnel, but the former is not available in the Marsh.

https://www.alweld.com/custom-boats?lig ... -j2tao6ju2

Will it help a prop or a jet? The factory says that most run a prop with it.
We run rocky tail water rivers with few public access ramps, so the Hyde drift boat will not motor the distance.

Thanks
 
I find it really surprising they wont put the marsh tunnel in the marsh boat model. Either way the performance tunnel for a prop is going to be a waste of money. You could get the same effect with a jack plate and some setback and a cupped prop. And not have to deal with the loss of draft. It sounds to me though that you need a jet. Thats an even different tunnel if you go the tunnel route. Alweld is typically a build it like you want it company. I hope they're not changing that. I have had several of their boats.
 
I agree it's a waste, asked that question of the factory. They do make a larger tunnel in the Mud Series.

They said "Marsh has only the small tunnel." They also said they were "selling a lot of Marsh Series with a prop and small tunnel." I think the jet would do fine with it. Even the Mud tunnel is smallish too but looks like it's vented from the factory.

https://www.alweld.com/custom-boats?lightbox=dataItem-j2tao6ju1


Going to look at the Alumacraft today. It has a similar build to the Lowe roughneck I used to run with a prop/tunnel.
 
Just because they are selling a lot of them dont make them worth a crap. If you're looking at alwelds dont pass up looking at weld-craft and southfork. Same kind of deal and just as good if not better. Probably the majority of aluminum boats on the river here are weld-craft. They're solid. Also produced in arkansas.
 
What area are you in? If your willing to travel I wouldn't rule out custom builders a lot of times you can get a lot better boat for not a lot more from a custom builder as you can get supposedly custom boat from big manufacturers. To me the performance tunnel looks more like a jet tunnel and the mud tunnel looks like one for a prop. If your considering tunnel hull talk to some other manufacturers like wooldridge who I'd venture to say have one of the best obj tunnel designs. Not saying they are the only one or the ones to get, but seems like a lot of people have had issues with tunnel hull set ups, but very rarely are the issues with wooldridge boats or ones similarly designed. I'm not a tunnel expert, or boat designer, but from what I've gathered seems the boats with obj tunnels that work the best are ones with slight dead rise in the bottom, some outward strakes on the bottom, and I guess what you would call a delta pad area in front of where the tunnel starts. My understanding is the dead rise helps air evacuate away from the tunnel preventing cavitation, the delta pad in front of the tunnel helps with having good flat flow of water coming into the tunnel, and the strakes help lift the hull while it's underway, they also help it to plane out a little higher, and help with turning. Like I said I'm buy no means a boat design expert this is just what I've gathered from my own research on tunnels out of curiosity. Sure they work on flat bottoms but seems like they aren't optimal on flat bottom or nearly flat bottoms.
 
I'm in northwest NC and familiar with the west coast boats. Owned Kofflers (built like tanks RMTB 14') and now row a Hyde lowpro metal with uhmw bottom. Our problem here is lack of access and having to run 6 miles to get up in the tailwater and a drift boat only makes 4-5mph. Very rocky freestone rivers.

Pricing a 1756 Alumacraft this week, all ready priced the Marsh Series Alweld performance tunnel. I like their no side rib design and fit and finish is very good.

The 3" Alweld tunnel would work well for a jet. The factory says 40/30 Yamaha will do fine on this model and I don't need speed. https://www.alweld.com/custom-boats?lightbox=dataItem-j2tao6ju2
 
If your going to have more than two people or two people with any significant amount of gear go for a bigger engine at least 60/40 spinning a 6 7/8" impeller with a large series obj on it. That 40/30 will have a medium series obj on it with a 6 1/8 impeller most likely, which wouldn't be very good for moving a boat that size with much weight in it. If you make the trip to virginia james river jets makes pretty stout boats that guys up there like running similar rivers. Probably could find a deal on a used one around there in the 17-18ft range with a 90/65. This is just my opinion at the end of the day it's your boat get what you want, but for obj powered boats I wouldn't want anything less than a 60/40 powered boat of some kind. Even if your not after speed you at least want it to be able to plane out without needing an 1/8 mile to do so.
 
Thanks Andy, I'm equally on the fence between the Alumacraft 6" prop/tunnel and the Alweld jet 3" performance tunnel. The prices came in today, comparable trailer/options and 1756 boats are only $200 difference. The folks at Alweld said the 50/35 two stroke Tohatsu would run their hull .
 
It would run it I'm sure, but an engine that spins a 6 7/8" impeller will do much better. The tohatsu two stroke is a good engine one of the lightest in that power rating.
 
Planning to take the Hyde drift boat up a 7 mile section of river this week. It motors with either low hp prop or trolling motor, but, it's SLOW! Trying to determine if a smaller jon will be better suited to these two local rivers. May not get too far, it's a rock garden the whole length looking at google maps. But it's a great smallmouth run.

During the week, should be fewer paddlers to get mad at me. Another stretch without good shuttle service and ramps.
 

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