Better performance - 18x42 or 18x48 tunnel hull?

[redfish150]

What would perform better, 1842 or 1848 tunnel hull? I'm running a Mercury 40 3 cylinder?
Anyone have any experience with a 1848?

[weedeater]

I have a Nissan 40TLDI on an 17x44 and like it, it gets up shallow and runs well (30ish loaded).....

[Montauk17]

1842 will run better due to the lighter weight....1848 weighs a good bit more. My podna runs a 1842 southfork tunnel with a 60 merc 2 stroke,thing is awesome in the the mud.

[cmcnabb]

Wider boat will probably run better

[FF_T_Warren]

Wider will carry a load better. If u ever plan to switch to a surface drive I would not get a tunnel hull.

[Natural Light Kid]

Originally Posted by FF_T_Warren

Wider will carry a load better. If u ever plan to switch to a surface drive I would not get a tunnel hull.

You can always have the tunnel closed in later if you decide to go surface drive.

[swamp snorkler]

wider also has more drag in the water

[SuperDave]

Longer and skinner will be faster with a light load. The wider boat will be slower but can carry more weight with less draft.

What are you going to use the boat for? Do you carry light or heavy loads?

Heavy loads, wider boat.

Is stability a concern? If so, wider boat.

The tunnel hull is nice when on plane, but it was squat more on take-off and draft more at rest.

[redfish150]

Boat will always run loaded. 2 batteries, lots of gas, fat boys, dogs, hunting and fishing gear and used to haul alligators too. Like the idea of better stability with wider but don't want to lose a lot of speed or hole shot?

[Nick1230]

Originally Posted by swamp snorkler

wider also has more drag in the water

Incorrect. The wider the boat is the higher it will sit out the water which means less drag.


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[cmcnabb]

Originally Posted by Nick1230

Incorrect. The wider the boat is the higher it will sit out the water which means less drag.


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I agree

[Bart Bridges]

I run a 2000 1842 tunnel with stock Merc 3cyl 60HP & 4 blade prop. I run 32.5 loaded down with 10 year old, Brownings, 2 dogs, a limit of ducks, and my big boned hunting partner. I don't know if his weight or wind resistance causes me more loss of performance. I have had 28 alligators and my BBHP and still got up on plane but had to run the bilge pump the entire way back.
All I know is the longer you go past 40 years of age, stability of the boat becomes more of a concern.
I could probably cut back on CFM sandwiches, that may help a bit also.

[j.e.hagen]

I have 18x42 weld built tunnel with a 3 cylinder 2 stroke mariner on it that runs 36 with just me and a gas tank or with me and mcnabbs chunky *** his dog and our huntin gear it runs 36 no matter what with a 15 pitch slightly cupped 3 blade prop and a vented tunnel

[SuperDave]

1844 with a manual jackplate.

[jchief]

For what you want the boat for, if it was me, I would go with the 48. It should carry more easier

[j.e.hagen]

If it was me and I had the money I'd go with the 48 also it's gonna be quite a bit more but a much more stable and handling boat I wouldn't worry with speed so much if your gettin a tunnel ur not gonna be racing so speed is a lagniappe

[Bad Boy]

I have a 18' x 42" Southfork Tunnel with a 2 Stroke 60 Merc and a 15 pitch 4 Blade Power Tech on it. I am still in the process of getting the bugs worked out of it but I can only get 31 mph out of it. I need to get my power trim working and it feels like the 15 pitch is to much for it. My question is how are these guys with the same hull and less HP running 40 & 43 mph? I would like to see at least 40 mph am I asking to much are these tunnels that slow?

[Montauk17]

Originally Posted by Bad Boy

I have a 18' x 42" Southfork Tunnel with a 2 Stroke 60 Merc and a 15 pitch 4 Blade Power Tech on it. I am still in the process of getting the bugs worked out of it but I can only get 31 mph out of it. I need to get my power trim working and it feels like the 15 pitch is to much for it. My question is how are these guys with the same hull and less HP running 40 & 43 mph? I would like to see at least 40 mph am I asking to much are these tunnels that slow?

Has alot to do with the motor height as well....if your motor is too low it will cause alot of drag.

[scott craft]

Originally Posted by Bad Boy

I have a 18' x 42" Southfork Tunnel with a 2 Stroke 60 Merc and a 15 pitch 4 Blade Power Tech on it. I am still in the process of getting the bugs worked out of it but I can only get 31 mph out of it. I need to get my power trim working and it feels like the 15 pitch is to much for it. My question is how are these guys with the same hull and less HP running 40 & 43 mph? I would like to see at least 40 mph am I asking to much are these tunnels that slow?

CajunChristian could help you with your prop and setup. You should probably get more out of it than what you're getting. I would take with a grain of salt anyone saying they are running 40-43 on a tunnel with a stock 40.

[CajunChristian]

First thing you need is a tach, can't tell anything without one. If you don't know how many rpm's you are turning, how can you make any adjustments???
I can assure you, a 15 is waaaay to much prop on a tunnel boat for that motor. Once you add enough cup to that 15 to stop cavitation, the average pitch goes to about 17 or 18 pitch, a 60 can't turn that much pitch. My guess is you are turning right around 5000 rpm, if that. That motor makes the most torque at 6000 rpm. Torque moves the load, not horsepower.
D