What size prop do i need...

[dotandjohn1]

I have a 1976 Monark 17B with an 85hp mercury...im getting ready to buy a new prop, however i cant figure out which one to get (pitch and diameter)...i pull tubes with the boat now and use it for fishing...currently it has a 26 pitch alum...is that a good size propeller or should i go with one bigger or smaller...Thanks for any info. John

 

[Robbabob]

Re: What size prop do i need...

Hello Dot and John and welcome to iBoats!

Take a look at the top of the prop forum page, you'll find what we call "Stickies" at the top of the list. These stickies are like little reminders telling us what information is necessary to allow us to help you. We'll gladly assist once we know more about your current setup and what you want to correct.

Thanks!
Robb

 

[dotandjohn1]

Re: What size prop do i need...

Well that sums it up the easy way...im going to go with the 19p...i kinda wished all questions were answered that easy...and since i can buy two alum. for less than a stainless one im ordering two today...Thanks John

 

[steelespike]

Re: What size prop do i need...

How did you come to that conclusion? Did you figure out your present rpm and speed, and your slip numbers seem ok?
Did your gear ratio seem to be right, And a 7" reduction in pitch would put you near your motors wot rpm.
Is the Monark 17B a light fast boat?

 

[dotandjohn1]

Re: What size prop do i need...

This boat only weighs 720lbs dry...its a very light boat...from what i seen on the test performed on the different sizes and pitches a 19 or 20 would possible be the best choice...

 

[wissam]

what size prop is ideal for my boat

what size prop is ideal for my boat

hello,

just bought a 26' cruiser (its called silvercraft 26 dubai made boat) and it has 2 115 four storke mercury engines on it, i noticed that some time the rpm is going up and the boat is bearly moving then when u put on full speed it takes time to get there, i contacted the agent and he said that the problem is that my propeller is 19' and he suggested changing it to 17' claiming that this would solve the problem and am not convinced. what do you think about what is he saying and what do you think is the ideal propeller size for such a boat (btw wieght of boat is 3300 pounds) and i use it for sometimes pulling a tube and sometime fishing in open sea.

 

[Robbabob]

Re: What size prop do i need...

This boat only weighs 720lbs dry...its a very light boat...from what i seen on the test performed on the different sizes and pitches a 19 or 20 would possible be the best choice...

It seemed the 26P was rather aggressive, but a 7" change could mean there is something else at stake. OR, the previous owner put something on that was ridiculous.

I hope it all works out -- using the stickies can be quite rewarding!

Happy boating

 

[Robbabob]

Re: what size prop is ideal for my boat

Re: what size prop is ideal for my boat

hello,

just bought a 26' cruiser (its called silvercraft 26 dubai made boat) and it has 2 115 four storke mercury engines on it, i noticed that some time the rpm is going up and the boat is bearly moving then when u put on full speed it takes time to get there, i contacted the agent and he said that the problem is that my propeller is 19' and he suggested changing it to 17' claiming that this would solve the problem and am not convinced. what do you think about what is he saying and what do you think is the ideal propeller size for such a boat (btw wieght of boat is 3300 pounds) and i use it for sometimes pulling a tube and sometime fishing in open sea.

Hi Wissam and welcome to iBoats!

Please start a new thread post with this same information. It keeps us al on track to what data goes where.

Thank you,
Robb

 

[steelespike]

Re: what size prop is ideal for my boat

Re: what size prop is ideal for my boat

Hi Wissam and welcome to iBoats!

Please start a new thread post with this same information. It keeps us al on track to what data goes where.

Thank you,
Robb

There is a new thread tab at the top of the prop forum.
Before starting the new thread read"read this first" and get us as much info as possible.

 

[steelespike]

Re: What size prop do i need...

I did the same thing the boat is 26' with twin 115s with 19" pitch.

 

[wissam]

Re: What size prop do i need...

I did the same thing the boat is 26' with twin 115s with 19" pitch.

you changed to 17" and it worked better?

 

[steelespike]

Re: What size prop do i need...

you changed to 17" and it worked better?

I was referring to robbabob mistakenly thinking he was running a 26" prop.when actually
was a 26' boat.
17" props would normally improve hole shot over a 19.But we need the info from the Qs in "read this first"
before any changes.

 

[Robbabob]

Re: What size prop do i need...

Come on guys, move this thread. I was not mistaken in my comment regarding the 26P as it was a comment to DotandJohn [OP]. I then asked Wissam to move his comment to a new thread to keep any confusion to a minimum; which keeping his comments have caused confusion as to which post I was talking, then Wissam got confused about a comment Steel made... and so on.

Steelspike has a gigantic amount of experience over me -- and I respect his word to the end. I do try to help where I can... and I can help; because we all make mistakes and don't hold a grudge when useful information is presented.

Thanks guys, I knew you would understand.

Happy boating!