Help chosing the correct prop for a slightly unusual speedboat.

[limecc]

Prerequisite is to optimise engine height or else the final pitch choice may be different or even no change be needed!

Start with the AV plate 1 hole (20mm) above level with keel and if it doesn't ventilate raise it another hole or lower it if it does.

If it's fixed trim those holes are another thing to experiment with so you're not scrubbing speed burying the bow.

 

[Crunk]

UPDATE!

I feel like a bit of an idiot but will share my idiocy incase it helps anyone else in the future.

The Suzuki Diagnostic cable arrived today so I was able to check for any fault codes: None!

Fired up the motor and checked the RPM, at idle it more or less matched what was on the dashboard gauge however when I increased the rpm to 2,000 on the diagnostic reading it was only showing 1,100rpm on the guage. It suddenly occured to me that I hadn't adjusted the scaling on the dashboard gauge! As it was reading correctly at idle I had completely overlooked scaling at higher RPM.

The scaling is now correct so I will hopfully get a chance to test the boat in the water this weekend. It may well be that I still need a different pitch prop as it still doesn't "sound" like it's hitting 6,000rpm but at least I'll be working from reliable data.

 

[ChromeDome]

UPDATE!

I feel like a bit of an idiot but will share my idiocy incase it helps anyone else in the future.

The Suzuki Diagnostic cable arrived today so I was able to check for any fault codes: None!

Fired up the motor and checked the RPM, at idle it more or less matched what was on the dashboard gauge however when I increased the rpm to 2,000 on the diagnostic reading it was only showing 1,100rpm on the guage. It suddenly occured to me that I hadn't adjusted the scaling on the dashboard gauge! As it was reading correctly at idle I had completely overlooked scaling at higher RPM.

The scaling is now correct so I will hopfully get a chance to test the boat in the water this weekend. It may well be that I still need a different pitch prop as it still doesn't "sound" like it's hitting 6,000rpm but at least I'll be working from reliable data.

Well, as rpm are crucial so are means of reading them. When i doubt use a laser gun -reads anythng that turns