Hi!

I will test out Bravo One propellers on my twin Merc 2.5 EFI SS setup. To get the rpms up, I have been reccommended to make vent holes (PVS) like Merc use on their outboard propellers such as Laser II, Tempest, etc.

How large holes should be used?

Can BBlades or Throttle Up make such?

Other Phantom 25's running this setup use twin Chopper II 28 pitch props. Should I concentrate on the same size with the Bravo One propellers?

Cheeeers, Toffen G

bblades is making me a set of Bravo I's with vent holes.

Putting vent holes in Bravo Propellers is a common practice. The vent holes are rather large, typically in the .75 to 1.25" range.

Stainless is not an easy material to drill. We use a CNC mill to cut the vent holes. We have found the mill will make a much cleaner hole than a drill bit does plus we can make virtually any size hole we want.

Matt

We started this process at Mercury Racing in the late 90's with the inception of the 300 Pro Max. The engine had a low rev limiter and was used on Bass boats requiring large propeller pitch. The Bravo 1 prop was one of the few props we had with high enough pitch offerings to hold the rpm's to 6400 and perform on a 21-22 foot bass boat. The low end torque however wasn't there to get the prop spinning enough to get out of its own way. Trouble to get on plane and trouble to get on the trailer. We started drilling holes in the hub and it fixed the problem. We usually go with 1" hole on the Bravo propellers, but do adjust it as needed. When the prop was retooled in 2000 to the current configuration, I asked for the PVS system to be installed in the Bravo props but was shot down because of cost. The Mirage Plus got the PVS system though because we knew it ran on more outboards than the Bravo 1. We see the Bravo 1 on many outboards now and drill many holes.

The location is important to achieve maximum results.

So what do those vents on my laser 2 's give me? I did total re power this season and may not be able to use them any more but I'll start there.

is this something that can be done to hydros

It can be done to pretty much any propeller with a large exhaust tube. It depends on the inner hub attaching webs. Their location can affect the ability to locate the holes correctly.