Prop diameter on SSM props
#11
VIP Member
VIP Member
Thread Starter
Re: Prop diameter on SSM props
Thanks Matt,
I'll gather as much data as I can when I run it with the new power and go from there.
Randy,
You are correct about the boat being very stable in the 90-109 mph range with the 16 x 33's. I really didn't get enough seat time in it to fully "figure out" how to run it...or dock it. Those props spinning in were tricky around the docks!! There is nothing like running a boat with twin 1200's, dry exhaust and a flashy paint job until everyone is watching and you look like a 12 year old trying to park for the first time!!
With the new engines, I'll be turning the props out...but still running the dry Stellings
I'll gather as much data as I can when I run it with the new power and go from there.
Randy,
You are correct about the boat being very stable in the 90-109 mph range with the 16 x 33's. I really didn't get enough seat time in it to fully "figure out" how to run it...or dock it. Those props spinning in were tricky around the docks!! There is nothing like running a boat with twin 1200's, dry exhaust and a flashy paint job until everyone is watching and you look like a 12 year old trying to park for the first time!!
With the new engines, I'll be turning the props out...but still running the dry Stellings
__________________
Happily retired and living in Heavens waiting room.
Happily retired and living in Heavens waiting room.
#12
Registered
Re: Prop diameter on SSM props
Originally Posted by OldSchool
With #6's???
I asked the question because I am re-powering my Top Gun with a pair of lower HP engines. It was running 16.5 X 33 four blades @6000rpm's. I've got a pair of 16.5 X 29's to try when I get the boat back. I no idea if they'll be right or not...but I'll be finding out in a few weeks
I asked the question because I am re-powering my Top Gun with a pair of lower HP engines. It was running 16.5 X 33 four blades @6000rpm's. I've got a pair of 16.5 X 29's to try when I get the boat back. I no idea if they'll be right or not...but I'll be finding out in a few weeks
#13
Registered
Re: Prop diameter on SSM props
Originally Posted by OldSchool
Thanks Matt,
I'll gather as much data as I can when I run it with the new power and go from there.
Randy,
You are correct about the boat being very stable in the 90-109 mph range with the 16 x 33's. I really didn't get enough seat time in it to fully "figure out" how to run it...or dock it. Those props spinning in were tricky around the docks!! There is nothing like running a boat with twin 1200's, dry exhaust and a flashy paint job until everyone is watching and you look like a 12 year old trying to park for the first time!!
With the new engines, I'll be turning the props out...but still running the dry Stellings
I'll gather as much data as I can when I run it with the new power and go from there.
Randy,
You are correct about the boat being very stable in the 90-109 mph range with the 16 x 33's. I really didn't get enough seat time in it to fully "figure out" how to run it...or dock it. Those props spinning in were tricky around the docks!! There is nothing like running a boat with twin 1200's, dry exhaust and a flashy paint job until everyone is watching and you look like a 12 year old trying to park for the first time!!
With the new engines, I'll be turning the props out...but still running the dry Stellings
#14
Offshoreonly Advertiser
Offshoreonly Advertiser
Re: Prop diameter on SSM props
Old School,
I know I'm getting into this conversation late. I was out of town for the Holidays. I love working with these types of situations.
Working with #6 drive propellers can be tricky but the options you have are also largely diverse. As Matt stated, there are many different issues to consider when working with #6's.
You kind of answered your own question when you mentioned the fact that the boat handled great with the 33's. If you are only decreasing HP, keep the same diameter and decrease the pitch! The boat will be the same old boat but a little slower. Now that being said, it depends on the history of the props in question. By that I mean do they match on a basic geometry level? We would need to measure that.
OK, now we are talking about changing rotation. Everything changes from here as far as our original handling base line is concerned. Yes, your docking will improve. Every other characteristic will also change. From planing to trim characteristics will be different.
Do what you said, test, take notes, retest and we can talk some more.
To answer the original question.................................
changing diameter changes "many" things...................
depending on the boat, too many to list........possibly.
Best advice, use as much diameter as the boat will "allow" you to use!
If you would like, call us anytime and we can go deeper into the subject.
I know I'm getting into this conversation late. I was out of town for the Holidays. I love working with these types of situations.
Working with #6 drive propellers can be tricky but the options you have are also largely diverse. As Matt stated, there are many different issues to consider when working with #6's.
You kind of answered your own question when you mentioned the fact that the boat handled great with the 33's. If you are only decreasing HP, keep the same diameter and decrease the pitch! The boat will be the same old boat but a little slower. Now that being said, it depends on the history of the props in question. By that I mean do they match on a basic geometry level? We would need to measure that.
OK, now we are talking about changing rotation. Everything changes from here as far as our original handling base line is concerned. Yes, your docking will improve. Every other characteristic will also change. From planing to trim characteristics will be different.
Do what you said, test, take notes, retest and we can talk some more.
To answer the original question.................................
changing diameter changes "many" things...................
depending on the boat, too many to list........possibly.
Best advice, use as much diameter as the boat will "allow" you to use!
If you would like, call us anytime and we can go deeper into the subject.
__________________
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
#16
Offshoreonly Advertiser
Offshoreonly Advertiser
here's a old one brought back to life.
My diameter is more blades area. This means better efficiancy, cruise and top speed due to more water being moved.
However, adding diameter decreases rpm and increases stern lift. If your boat becomes negatively affected by these changes, reducing diameter is required.
Therefore, use as much diameter as the boat allows you to.
My diameter is more blades area. This means better efficiancy, cruise and top speed due to more water being moved.
However, adding diameter decreases rpm and increases stern lift. If your boat becomes negatively affected by these changes, reducing diameter is required.
Therefore, use as much diameter as the boat allows you to.
__________________
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]