Whaler Central - Boston Whaler Boat Information and Photos

Posted by timt1 on 10/31/10 - 8:24 PM

Has anyone heard of or had experience with holes drilled on circumferance of prop hub at the base of each blade ? I believe some props even came factory drilled as such for performance.

Posted by Ralph Iorio on 11/01/10 - 5:15 AM

Just spent a bunch of time looking for the correct prop for my rig and in the process handled quite a few new and used at dealers and marinas. Not one time do I recall seeing anything like you're describing nor have I heard of such a design. Not being an engineer of any sort, can't imagine the benefit of such holes in the hub.

Posted by CES on 11/01/10 - 5:21 AM

The holes you're referring to are on the hub of the prop and are used on higher performance props to help prevent ventilation. Typically you'll see the holes in the hubs when the props don't have a ring on the end of the hub or the hub isn't bent upwards toward the end of the hub.

Edited by CES on 11/01/10 - 7:38 AM

Posted by scrimshaw on 11/01/10 - 8:48 AM

On acceleration, exhaust is drawn out of the vent hole. When the propeller blade strikes this aerated water, it pushes through it much easier than it would solid water – causing engine rpm to increase more rapidly. Once you’re on plane, the water flows over the vent holes and seals in the exhaust, allowing the propeller to again operate in solid, nonaerated water.

Posted by Finnegan on 11/01/10 - 4:24 PM

Prop vent holes have been a staple in Mercury's performance prop arsenal for over 20 years. You can learn everything you need to know here:

http://www.mercurymarine.com/propelle...ogies/pvs/

Many new Boston Whalers come with vented design Mercury props such as the Mirage Plus, Revoulation-4, Enertia, and Laser II.

I would not drill holes in a prop that did not come that way from the factory, and indication they are not needed. They are generally not used on any HP engine 60 or less.

If you englarge this photo full size and look carefully, you can see the prop vents in these Mercury Revoution-4's on my 200 EFI's. I am running the largest diameter vent plugs.

http://smg.photobucket.com/albums/v42...CN1464.jpg

Posted by Tom W Clark on 11/03/10 - 8:01 AM

#10

Vent holes o propellers are very common these days. As mentioned above, they serve to help an outboard accelerate by allowing some slip but for the vast majority of Whalers there is no point in using them because most Whaler do not struggle to get on plane.

Furthermore, vent holes can be a nuisance if you accelerate onto plane gently or try to hold plane at low speeds.

There are some large, marginally powered Whalers that make good use of vented propellers but these tend to be four strokes that have a hard time generating much torque until they achieve a certain RPM.

If you waterski with your Whaler, you may benefit from vent holes to help compensate for the sudden heavy load of a skier.

The Mercury props with their PVS vent hole system is the best because you can simply snap plugs into the vent holes which is the first thing I do when I install Mercury props on my boat.