sportsmaster

[water]

Hello nice guys I have a sportsmaster on a 200 hp 2.5 litre the sportsmaster is with the fat shaft on it I have a tempest 27 p with solid vents plugs it`s rpm are 5700. it`s plane good.
If I make the vents plug the large ones what are the advantages, incraese about the last 100 rpm to 5800 ?????
Thanks very much

[Raceman]

Vent holes are about gettin' sluggish boats on plane. They won't increase top end.

[boilerdawg]

like raceman says the vent holes in the prop are to allow for exhaust gases to escape from around the center area of the prop. this gas will make the prop cavitate/slip and help spin up the motor to get you on plane faster.

[ssmith007]

Could he have the prop reworked to 1 or 2 degrees less pitch? I would think you would want the vent holes open. Good luck. Smitty

[boilerdawg]

Could he have the prop reworked to 1 or 2 degrees less pitch? I would think you would want the vent holes open. Good luck. Smitty

the vent holes are adjustable to help keep prop blow out to a minimum while gettin on pad. to much opening and the prop blows out, not enough opening and the longer it takes to get on pad. thats the total purpose of the vent holes in this prop.

sure he can change the pitch of the prop and increase rpm...but does that equate to more boat speed? i think he'd hafta look at what rpm range that motor makes its horse power and prop it accordingly.

[water]

Ok guys thank for your threads but another question which are best vents to from midrange to top end for eg from 3000 rpm to 5000 or more thanks guys ??????