On my buddy’s boat i noticed on his Rampage (or raptor?) SS props he has exhaust vents on the front of the prop. controlled ventilation?
On the port motor they are open, on Starboard they have rubber in the hole, like it can be removed if needed.
My question is…
is this normal for twins?
shouldn’t you notice a rpm difference in the 2 motors at WOT? there is none.
What do these holes actually do?
should he remove the rubber from the prop that has filled holes?
Thanks!
the holes introduce air to the blades so that the prop spins up faster at take off. once forward motion increases water pressure basically seals the holes. there is no effect on top end, just a holeshot aid.
I don’t know of a reason why one prop would be without plugs and the other with. You can get plugs that have a variety of hole sizes to adjust the amount of air introduced to the prop thereby adjusting the amount of slip during holeshot. regardless, having no plug at all is going to induce too much slip, especially in that application and making the other engine work harder during acceleration. I would install plugs in the prop without before taking the out of the prop with. You can always drill progressively larger holes in them to dial in the holeshot.
Iain Pelto
Edgewater 185CC “Jumpin’ Bean II”
Native Manta Ray 14