Topic: MEMO on Proper Hole Shot Ventilation!

Just for the records sake! We have had lots of repetitive questions on hole shot. So we are hoping this explanation will help to reduce some of those questions. We at BCB prefer to have about a 1 to 1 1/2 second ventilation of the propeller as the nose of the boat begins to fall over on the hole shot. Not all boats have or need this, though if your set up does don't worry about it. This ventilation increases RPM and mid range. Keep the throttle pressed down and allow the full ventilation cycle to occur. If you can not keep your throttle down and get that 1 to just under 2 seconds of ventilation to finish the cycle, then: 1. you either have too much venting out of your propeller hub, 2. you have yoru engine too high, 3. or you have too large of a prop on your rig? This is of course is based on all thing being mechanically right on your outboard. And no hull or internal issues are present on your boat. We hope this helps many of you to understand your goal! Get the height first for performance on top, then the ventilation for your hole shot. BCB

This topic has 4 replies, 3 voices, and was last updated 18 years, 11 months ago by Bass Cat Boats.

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May 14, 2006 at 11:33 pm #438023

basscathash
Participant

I understand both points 1 & 2 but #3 about too large a prop confuses me. My boat blows out just as it breaks over, I let off and hit it again and it hooks up and does fine. It has done this on every prop I have run: 26P & 27P Tempest and 26P Trophy. This is on a 05 Classic with a 05 DFI Yamaha. I thought a larger prop would just bog down.

Brian Hash

May 15, 2006 at 12:50 am #438024

Bass Cat Boats
Keymaster

Yes too large of a propeller will ventilate on most rigs which vent when coming on plane.

They do not have horsepower and thus not enough RPM’s, so the hub ventilation pops the back side of the blade vacuum and poof, no hole shot.

There are two things a larger propeller will do. Just not come out of the hole at all, and ventilate and never break over, unless you feather it up.

When you hold your throttle down, YOUR boat should come on out without loosing bite for more than 3 seconds, and we prefer 1 second.

If you HAVE to feather the throttle, then you have to adjust vent plugs, exhaust rings, or go to a different style or smaller wheel.

That is unless you are running a chopper as you mentioned.

BCB

May 15, 2006 at 10:29 am #438025

Htharp
Participant

Just to be sure I understand, what is happening to the trim during this time of ventilation? Should you be bringing it up, or wait until the ventilation is complete?

May 15, 2006 at 2:22 pm #438026

Bass Cat Boats
Keymaster

Trim as soon as ventilation is finishing.

BCB
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