I realize most the people on this forum don't have the same requirements as I. On the off chance this info could help someone I thought "why not"?
I just picked up an old 24' X 60" Monarch with a decent bottom. The largest I've run, previously, was a 24' X 48" Alweld with a 35 SD. After taking care of some cosmetic repairs on the Monarch I mounted a High Transom SD on it and took it to the river. I loaded it down with about 1000 lbs not including the engine and battery. This is close to the load I have on a 5 day fishing trip on the Yukon. Upstream speeds in the current was 18mph. If I ran in the eddies next to shore it climbed to 20mph. Downstream speeds were consistently 23-24mph My best speeds came with the tach reading 3550-3570rpm. The engine is a box stock Briggs. Steering was very easy with no push or pull if the load was heavy on one side. Shifting considerable weight forward only decreased speed by 1 or 2 mph. If I kept the load balanced fore and aft the boat only drafted about 4 inches. I was impressed! I really didn't expect it to perform that well.

Thats pretty good for a stock motor.Good info

Stu, can you try running a prop with less pitch to get the RPM's up some? IIRC the 3500 RPM rpm range isnt the best to run the engine at a heavy load. 3700-3800 would be ideal and have more mechanical advantage.

That's a good idea there white Marcus.

Yep Briggs don't like being loaded down and run 3500-3600 rpm's . They create a bad vibration and shit will happen lol!! When I bow fished out my small boat I ran a prop that would turn 4000 with my normal load!!

Critical speed,for those that don't know google is your friend

Hats off to you once again Mr Stu

without photo's it's all talk.........Duckdon

Sweet. I would be curious to know if it does better. Theoretically speaking when pushing that much of a load you want some mechanical advantage to help you out and get strain off the motor! Sounds like you got a plan!

Now that's a Yukon runner........ I'm in on the pike fishing just don't know when I can fit it in. Duckdon

Just came to me..........That's a late "70's" vintage riveted boat with maybe a .83 thick hull and it's still getting the job done. Nice........Duckdon

That's Awesome!
You could bring 6 people hunting along with their personal pirouges and still have room.

Let us know how the new gears do stu I'm curious to see if it gets your rpms where they need to be

Stu Congrats on 50 years of marriage!

Damn good job!!! 50 years and fishing and hunting Alaska today! The good life.

Stu, Congrats on the 50th!

I'm curious about those RPM's too. Got your bud to weld my tunnel off...still not gettin it.
John