Rumbling coming from prop area when in gear

[jellyellie]

Hi guys

So, just got my engine working again (the old starter motor died, fitted a new one yesterday, works a treat) only to find there is now a really horrible loud vibration/rumbling coming from the prop area when I run her in gear. The rumble isn't coming from the engine, gearbox or prop shaft; when you stand outside in the cockpit and put the engine in gear it comes from right beneath you.

It's a horrible noise. I'm guessing it might be the cutlass bearing? Or maybe excessive barnacle growth/bits of weed whacking round and hitting the bottom of the hull? Any ideas? I was planning on sailing her to Shoreham to dry her out on a tide and anti-foul to save on the extortionate lift-out fees here in Brighton, but I guess I'll need her in the yard for a while if this is something big.

Any suggestions? Take her out and have a look?

Thanks!
jelly

 

[sarabande]

nobble a passing diver to take a pic for you before decding on further action.

When is the last time you used the engine and gearbox to turn the prop ?

 

[nigelmercier]

nobble a passing diver...

I'm sure jellyellie can go down herself.

 

[vyv_cox]

Propshaft anode come loose? Rope cutter likewise? When the bearings on a Stripper wear out you hear a knocking noise at x2 shaft revs as each blade passes, so probably not that from your description. I have fixed both of those using a mask and snorkel, so don't rush to haul out.

 

[jellyellie]

Yeah, I'd like to see what's under the water but you're not allowed to dive in the marina (even commercial ones) and I don't fancy "falling in". How about a waterproof video camera? That might work.

It's been two months since I last went out for a sail, thus turned the prop with the engine/gearbox. (I know that I need to do this much more regularly, and will do now I have the new starter motor fitted - well, need to sort this rumbling out now too.)

 

[nigelmercier]

How about a waterproof video camera? ...

Try looking on eBay.

 

[rjp]

I've occasionally had nasty rumblings and vibrations from the prop area when I haven't used my boat for a time. Always sorts itself out after a run, so I've put it down to fouling probably unbalancing the prop.

John

 

[Vara]

I've occasionally had nasty rumblings and vibrations from the prop area when I haven't used my boat for a time. Always sorts itself out after a run, so I've put it down to fouling probably unbalancing the prop.

John

+1. Just pile some revs on and you might well find it clears, if not shouldn't do any harm.

 

[Spyro]

If it's not the anode or a cutter It could be the prop shaft hitting the stern tube. Do you here a loud bang or knock when you start it up?
Try putting your hand on the stern tube and see if you can feel it knocking.
Try motor sailing on either tack and see if it gets worse or goes away on one tack. if it does I'd put money on the shaft hitting the stern tube.
If it does turn out to be this you need to get the shaft aligned centrally in the stern tube.

 

[Poignard]

Yeah, I'd like to see what's under the water but you're not allowed to dive in the marina ...

Supposing you happened to fall in accidentally?

 

[Burnham Bob]

identical problem here too - usually does clear itself although i know my cutless bearing does need replacing. happens sometimes when the boat hasn't been used for ages. with the boat out of the water at the end of last season no problem seen. so it probably is fouling on the prop or similar.

 

[Ruffles]

identical problem here too - usually does clear itself although i know my cutless bearing does need replacing. happens sometimes when the boat hasn't been used for ages. with the boat out of the water at the end of last season no problem seen. so it probably is fouling on the prop or similar.

Me too. Caused by heavy fouling. Doesn't do the bearing any good either.

 

[bumblefish]

Hi, is the rumble present when going both ahead and astern? A friend of mine had a loose shaft anode which would only cause a rumble when going astern, I imagine it moved forward and rattled aginst the bearing.

 

[Ex-SolentBoy]

I assume that the noise and vibration are not there when you run in neutral.

What prop do you have?

 

[onesea]

Yeah, I'd like to see what's under the water but you're not allowed to dive in the marina.

If you have the gear surely you just do it one night? Bright torch, a friend standing by...

Try looking on eBay.

As a none diver I was tempted by one of these, do they actually work?

When we got this boat we got the occasional odd rumble, from its improved with use but never really got a hand on why...

 

[affinite]

Loose propshaft anode would be my guess also.
I dont think that an U/W camera will see that.
Cant you get the boat outside the marina for a look ? (tow with tender ?)

 

[Ex-SolentBoy]

I have one like this. http://www.maplin.co.uk/underwater-colour-surveillance-system-223963

Works perfectly, but of course you have to steer it to the right place.

 

[AIDY]

I have one like this. http://www.maplin.co.uk/underwater-colour-surveillance-system-223963

Works perfectly, but of course you have to steer it to the right place.

I have a black and white camera and monitor from maplins think i paid about 60 squid for it works perfectly for checking anodes on prop. i attach it to a boat hook saved me loads on lift out's over the years.

 

[charles_reed]

Most probable fouling, possible loose shaft anode, improbable loose prop.

 

[jellyellie]

Thanks for all your replies and suggestions.

Yes, it only happens when in gear - and is the same in both forward and reverse gears.

I'll run it a little more to see if it's fouling, but it really does sound horrible.

My dad is just down at my boat with me at the moment and has brought his waterproof video camera with him, I'm going to give it a shot and see if I can see anything. I would rather not go in the water.

This is the underwater profile/prop: