Porting or ventilating a propeller

[Horse]

Has anyone tried porting a prop to give a better hole shot without any loss of top end performance. The ones I have seen on the web normally drill three 1/4" holes just back from the leading edge of the blades. This allows exhaust gasses into the prop face while accelerating allowing higher RPM much faster. As the boat starts moving through the water the gases are sucked out the normal exhaust and the prop performs as normal. Mercury do a production model but I can't find out much more about the process for adapting an existing prop

[Swanie1975]

I have a trophy plus four blade prop on my suzi 140 with the vent holes. Mercury have plastic plugs with different size holes in them so you can adjust the amount of slip.

I tried it with no plugs and it just let the prop slip at any speed if I gave it a big amount of throttle. I then run it with full plugs for the last 12 months and was happy with it but hole shot was a little slow (IMO lol) so I bought the plugs with the medium sized hole and trialled those on the weekend and it has improved the holeshot a fair bit and it doesn't seem to affect it anywhere else in the rev range so I'm pretty happy.

If you do a google search for DIY prop venting you should come up with a diagram on where to drill or I could take some pics for you tomorrow in the light if that will help?

Cheers Ryan

[Spaniard_King]

The standard vent hole is 1/2 back from blade and 1/2 inch back from the machined section which sits inside the gear case

Start at 5/6 1/4 does nothing

[Horse]

It looks a bit scary drilling holes through the prop
http://s36.photobucket.com/user/cmarques1/library/prop%20vent%20holes?page=1

There is a bit of info out there but it all seems to be from the same basic source. This pic turns up a lot in various forms

http://smg.photobucket.com/user/perrycl/media/ventingprops.gif.html

[Dicko]

Maybe easier to get hold of a set of Mercury venting plugs & drill the prop to suit. The plugs then come in 3 different sized holes or you can then plug them up with blanks if you don't like it. Usually $2 to $3 each. Most merc dealers will have them.