VP folding prop vibrating in reverse

[Elliot_SG]

Hi all,

Yesterday during a fantastic sail, I anchored in a favourite spot and felt significant vibration when reversing. Went back into the marina later on and when trying to reverse into the slip as soon as I increased revs in reverse (to open the prop) there was a huge vibration and no reverse control. It felt like I had some (but not much) power in reverse, and I didn’t want to push it as didn’t want to risk damaging the gearbox. Ended up getting towed into the slip. My cleaner will dive down on Monday to check the prop. I’m hoping it’s just a barnacle or simple fouled prop, however the fact it works perfectly in forward gear makes me suspect something worse.

Any ideas or things to check on?

Yacht is a ‘05 Bav 39 Cruiser, with VP 130 sail drive and VP 3 blade folding prop. Prop was removed, polished, checked over and fitted with new anodes back in June this year and has since covered several hundred miles of both motoring and sailing.

[PEA-JAY]

When you engage reverse the thrust from the prop will be acting on the bearing housing and if somehow this became loose it could result in vibration during reversing. You would also find the oil in the sail drive contaminated by sea water. In forward the thrust is in the opposite direction and a loose housing will be pressed into place and there might not be vibration. I don’t think it’s to do with prop balance as it would be unbalanced in any direction. A loose prop hub central lock nut might also have the same effect.