Slipping or cavitating?

[Sorkarn]

Hello

Yesterday I went out for the first time with my just bought Tigé 20i -00 to do some surfing. Everything was well until u had the wave really great and the boat was under heavy load. It sounds and feels in boat like something is slippingtho when we tried Google it seems like slipping Velvet drive(71C) or the prop is cavitating. How does the boat act while cavitating? The prop is also changed from a 4-blade to a 3-blade, don't know make or model tho.

Happy if someone could tell me how to know if I should start with drive or prop!

[dj2]

I would recommend getting the prop make and model to help with troubleshooting.
Did you feel the “slipping” constantly while under way? Just when starting off? Just while turning?
How much weight did you have in the boat?

[chpthril]

Theres always a small amount of slip from a prop, but I think you are experiencing is cavitation or the prop just gulping air from the heavy weight and maybe listing over. It feels like a shudder and often times you hear a growl and the motor might rev a little.

best to know the props dia and pitch.

[bait28]

It will be helpful to identify what prop pitch and diameter the boat was designed for as you try to diagnose. Koolaid can probably help there. You can also call acme and ask for their tech to hep ID.

To ID prop on there now, look at the face of the prop shaft where the prop nut rests against. There are engravings record them and let us know.

Also, possible step to diagnose a slipping 71c: keep taps at 1. Accelerate and run near or at full throttle. Watch the rpms relative to mph (on your phone). If the trans is slipping you may see the rpms increase and mph stay the same or decrease.

Those transmissions are sensitive to fluid level. They will definitely slip if the fluid level is low and/or if the rise of the boat is substantial causing the internal pump to suck air.

[NICKYPOO]

I fought this same issue for a long time until I found the right prop. It’ll still do it if I really push the setup with too much weight in the back. Moving as little as one person up to the bow makes it go away.