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Hey all, did a quick search and didn’t find this question so I’ll ask it...

On a long run today at Lake Cumberland there was a lot of debris in the water. We felt a bump early in the trip but all seemed ok. Later, we were running at 3900 RPM (Volvo 8.1Gi) and suddenly lost speed. RPMs remained steady. Tried again and at higher RPMs before it planed it clearly topped out like the prop was spinning. High RPMs but no additional power. We limped home at 1500 RPM and took it in to the repair shop.

Seemed like what I’ve seen described as a textbook spun prop. BUT am also reading the Volvo Duoprop does not have the sacrificial hub that protects the drive train. Anyone have this experience - what was the issue and diagnosis? I’ll report what the shop says.

Thanks. Hope everyone is healthy.

Chris

Hopefully not the engine coupler. You smell rubber burning?

No, nothing like that. Checked the prop, no damage. Odd.

How's reverse?

Reverse worked fine. Didn’t rev it high though. I did notice that the boat shifted considerably smoother than before. No “clunk” when shifting in forward and reverse like before.

I know Merc B3 doesn’t have a sacrificial hub, not sure about the VP. We’re the props clocked when they were installed? Mine are, and I would be able to very easily see if they slipped at all.

Thought I’d chime in on this since I spun the hubs on my Volvo DPS FH4 props this weekend hitting sand at just over idle speed. Boat moved ok at idle speed to about 1500 rpm, but didn’t move much faster than 8-10 mph when revving up to 3500 to try to get on plane. Like Akor said, I could tell at least one had spun because the propellers were no longer clocked the way I had installed them, but I’ll likely punch marks on the prop and the hub for future reference before reinstalling.

Local prop shop (PropMD) said they see it more with the newer bronze hubs in Volvo props, and it’s an easy but expensive fix to pop in a new pair of hubs.

Btw, a pair of FH series helical spline hubs look something like this: