Question

[nola mike]

Even with a 21 that boat should not take a minute to get on plane with 2 people unless it's severely overweight, or the motor is not producing good power.

Once you get on plane what is your WOT?
What do you mean "Ok so I found it online it’s 13 3/4 X21 so 21 pitch I’m guessing"
How did you come up with that number?

Do you have the outdrive trimmed all the way Down / In when trying to get on plane?

Agree with this. Your boat should have zero problems getting on plane (2500# from what I looked up). Has the boat always been like that? How long have you had it? Whats the WOT speed and RPM (you should be 45-50 mph and 4400-4600 RPM). My 30 year old 4 cylinder with a tired engine still pops on plane and can pull anything short of my fat ass on a short single slalom (even I can get up, just takes a minute).

 

[JimS123]

I didn’t say I was going to put one on my boat. I was just asking what people thought of them. And I’m going to change the prop on my boat but was just asking if someone was running a hydrofoil and if they liked it or it helped or if it was worth buying that’s all!

A hydrofoil (the best model) is an awesome way to optimize the "performance" of your boat. I've documented data that shows that time after time. But first you have to have the hull / motor combination running reasonably well.

You clearly have a prop problem. Your boat performance is lousy. Fix that first so that you can drive the boat with a few people aboard, and then let's talk about making it better.

 

[nola mike]

You clearly have a prop problem. Your boat performance is lousy. Fix that first so that you can drive the boat with a few people aboard, and then let's talk about making it better.

He doesn't clearly have a prop problem. Saying that poor boat performance is due to the prop without other information is just wrong.

 

[JimS123]

He doesn't clearly have a prop problem. Saying that poor boat performance is due to the prop without other information is just wrong.

The specifications would indicate he has the wrong pitch prop. Surely the boat may be waterlogged or the engine might be crap, or the outdrive might have been replaced with the wrong gear ratio, or the tach is broken, etc. Nevertheless, its obvious that the OP does not have the knowledge or experience to solve the problem, and has been given bad info in the past. Thus, without further adieu, replacing the prop would be the easiest next step short of an on-site visit to trouble shoot his dilemma.

 

[nola mike]

Agreed, easiest next step. Also absolutely the wrong next step. Proper diagnosis is the correct next step. Just some info would be helpful. What specs indicate the wrong prop? His WOT? His RPMs? Calculated slip? Factory specs? Who knows what this guy's capabilities or knowledge are? This forum is great just because most of the advice does not consist of "throw some parts at it and hope it works".

 

[JimS123]

Who knows what this guy's capabilities or knowledge are? .

And therein lies the rub. It sounds like the info we might get back might not be accurate, so thus our recommendations might be wrong anyway.

As they said when puters were first invented...."garbage in, garbage out".

We all want to help. QQs have been asked already. Why don't you summarize them in bullet form and re-submit.

 

[roffey]

As they said when puters were first invented...."garbage in, garbage out"..

I am an IT specialist and have been in the business for 40 years, you made me crack a smile. I have not heard that expression in years. Ever heard of a PEBCAK error?

I'll not hijack this post any further...

 

[JimS123]

I am an IT specialist and have been in the business for 40 years, you made me crack a smile. I have not heard that expression in years. Ever heard of a PEBCAK error?

I'll not hijack this post any further...

No, we didn't have keyboards back in 1967, we had keypunches. So, gotcha beat at 53. Our laughs at the time was that the remote terminal was bigger than our VW Beetle, and the mainframe was bigger than the house.

No hijack, I just ran it thru my 286 and the data indicated that considering the size of the boat and the OP's desired usage a 17 incher would be appropriate.

 

[roffey]

No, we didn't have keyboards back in 1967, we had keypunches. So, gotcha beat at 53. Our laughs at the time was that the remote terminal was bigger than our VW Beetle, and the mainframe was bigger than the house.

No hijack, I just ran it thru my 286 and the data indicated that considering the size of the boat and the OP's desired usage a 17 incher would be appropriate.

I started with key punch for a wee bit and I still support mainframe computers for the Federal Government. I'm not 53 years but started in 1982 as a tape librarian (MVS/JES2). You would be surprised how many people say shut them down while the covid pandemic on ongoing.

I agree Jim. if he is having problems getting on plane, assuming his motor is running well and his boat is not water logged I would start with a prop swap. I bet he can borrow one to give it a try...

 

[JimS123]

I started with key punch for a wee bit and I still support mainframe computers for the Federal Government. I'm not 53 years but started in 1982 as a tape librarian (MVS/JES2). You would be surprised how many people say shut them down while the covid pandemic on ongoing.

I agree Jim. if he is having problems getting on plane, assuming his motor is running well and his boat is not water logged I would start with a prop swap. I bet he can borrow one to give it a try...

One last diversion to the thread and I apologize ahead of time.

On my very last trip to the mainframe with my classmate carrying huge boxes of (computer) punch cards we finally had the resolution to the Engineering Thesis resolved. At about 1AM he said come to my house and we'll have a beer. His sister was still up, home from college, and wearing a ratty housecoat and curlers. Two weeks later I took her for a boatride and she's been my first mate for 49 years now.

I just conferred with her and she said no question at all - 17 inch.

 

[Coalminer5156]

Ok thank u all for the replies! I do appreciate it FYI I bought the boat last yr. guy I bought it off of said it needed a carb I rebuilt carb new plugs wires dist cap basically a tune up. Took boat out had fuel probs first couple times then got it figured out. And wot is 4500to 5000 if I’m not correct. This is my first boat and I was used to my buddies 86 Supra that got on plane wright now lol. That’s why I was asking the ? I thought maybe a prop but just wanted to see what people had to say!