14' V with 25hp; What prop pitch to choose?

[AaronR]

I am getting my old fishing boat back in the water. I had a fuel problem with it and gave up on repairing it and parked it. I knew the prop had been slipping but for slow speed river fishing it never really bothered me, now I will be using it to fish on the lake and so I want a new prop for it.

My main question is with a lowe 14' deep, wide, V boat and a 1978 25 hp johnson would a 9,10,11,or 12" pitch work the best for me?

Currently the boat is just bare with no extra weight on the hull except a fish/depth finder. Eventually I would like to add a very small front deck and two seats so I would like to have this in mind when choosing a prop.

Any opinions or advice will be appreciated.

Thanks.

 

[usskydvr]

Re: 14' V with 25hp; What prop pitch to choose?

I'd go with the 11 pitch

 

[steelespike]

Re: 14' V with 25hp; What prop pitch to choose?

"standard prop listed in the brochure is 11" Thats a good start.
As far as decks and such keep in mind the boats rating.
Is the boat really a deep wide 14"?
While a healthy 25 can plane with 1100lbs total weight It may struggle if the boat is small.Regardless there wouldn't be much margin for more weight and a 14 may not be rated that high.
You also may want to use a couple of planks to help determine what its like to move around on a deck.Perhaps place some weight approximating a deck and see how the boat handles.

 

[AaronR]

Re: 14' V with 25hp; What prop pitch to choose?

I consider it deep and wide, it is 48" wide at the bottom and 26" tall up the sides, there are taller, but also some shorter.

I should have been more clear with my deck comment. I dont want anything huge, just would like to make the front area from the first seat forward(~2') level with the first seat so it is easier to get aboard the boat. The seats will just be bolted to the aluminum benches, I only plan to have two so I am assuming the total added weight will be in the ~150lbs range.

I was thinking a 10" or 11" myself but wanted to get more opinions.

If I went with a 10" how much top speed would I lose compared to the 11"?

My current prop doesn't say what it is so I have no idea where I'm starting. I believe my top speed before the prop started slipping to be in the ~20-25mph range from running with another boat that had a speedo.

Does this sound about right?

 

[steelespike]

Re: 14' V with 25hp; What prop pitch to choose?

In ideal conditions a healthy 25 should be close to 30mph lightly loaded
on a boat like yours.Aluminum boats speeds seem to vary widely over similar sizes.
probably due to bottom shape,number of keels and rivots.
I would stick with the 11 as it is intended for boats similar to yours.
Mount your motor as high as possible using sticks to support it while you tighten clamps.In the extreme you could gain a couple of mph. A new prop will allow maximum height.
You have the old style gearcase so your height may be limited.
Can't hazard a guess on speed loss with a 10 over 11; you would gain hole shot and ability to get on plane easier with an extra load.