small prop question

[bigeasy1]

This has nothing to do with my Tsunami,but only a question on a prop.I have a 17 ft aluminum boat for fishing small lakes when im not on the 23 Seacraft.
So,anyway its time for a new prop for this small motor(20hp 1986 Johnson).The 10-1/2 x 11 prop that's on it has a series of slots around the inner edge that faces the motor.
I found a replacement OMC prop with the same size and pitch and the same 14 spline shaft,and it fits fine.
The only difference is that it doesn't have the slots,its just a plain edge. Both are actual Omc props and are listed for this older 20 hp motor(1984 to 1997)

Can anyone tell what purpose the slots serve,and do they both function the same?
Thanks all

[Bushwacker]

Some props have 1/4"-3/8" vent holes in the hub near the pressure side leading of each blade. The purpose is to allow exhaust gas to blow out onto the blades to cause some ventilation and a lot of slippage when you first hit the throttle, to allow the engine to immediately rev up to it's torque peak. Same idea as the automatics with high stall speed torque converters back in the muscle car days. This would be particularly useful on props with very high pitch on high speed boats that have a poor hole shot.

How wide and deep are the slots on your little motor's prop? I doubt that they are large enough to cause ventilation, so my guess is that both props will have similar performance. Don't know why they would do extra work to machine slots into forward edge of hub.

[bigeasy1]

Thanks Denny it's appreciated. The slots are not very big, about 1/8" wide at the most and are only the thickness of the prop casting at that rear area.there is about 6 cut out slots around the prop so it leaves 5 or 6 small anchor points to keep it all one piece.
After reading your reply, I think it will be fine.75% percent of the time it will be trolling and the balance will be drifting and casting.

Thanks again

[gofastsandman]

Originally Posted by Bushwacker

Some props have 1/4"-3/8" vent holes in the hub near the pressure side leading of each blade. The purpose is to allow exhaust gas to blow out onto the blades to cause some ventilation and a lot of slippage when you first hit the throttle, to allow the engine to immediately rev up to it's torque peak. Same idea as the automatics with high stall speed torque converters back in the muscle car days. This would be particularly useful on props with very high pitch on high speed boats that have a poor hole shot.

How wide and deep are the slots on your little motor's prop? I doubt that they are large enough to cause ventilation, so my guess is that both props will have similar performance. Don't know why they would do extra work to machine slots into forward edge of hub.

I`ve seen this with yammi props.
Not sure why either.

Why would you want heat there?
Baffling.