Grounded Prop

[Jinks]

I'd be grateful if you guys could help with some advice.

Leaving Aberystwyth Marina at low water recently (just tick over speed) I swerved to avoid a fishing line, left the channel and grounded the prop which promptly stopped. Waited for the tide to float me, back in the channel and away to go.

Cruised down to Cardigan with no problems at all until slow reverse to moor when there was a distinct vibration. Had a look at the prop when the boat had dried out and there was a noticeable bend in one of the blades. Took advice from the local boat shop and the guy hit it with a hammer a couple of times until it was back - more or less - in shape.

Took the boat back to Swansea, again with no discernible problems (other than a sea off the Gower that I would NOT have been in from choice) and even the vibration in reverse had gone.

It is my intention to to take the prop off and send it away for reshaping etc., the question is when?

If I don't do it now am I likely to be doing any damage or can I wait until the end of the season when it comes out of the water for anti-fouling, service etc.

Thanks in advance.



<hr width=100% size=1>Of all the things I've lost - I miss my mind the most!

 

[duncan]

martin, firstly if it looks fine, and there is no vibration then it should be ok to run at cruise for a bit but you really ought to get it balanced as soon as practical.
what drive system are you using, and is the prop alloy or stainless? I thought the Yanmar 240 (4LHA-STZP?) only came with stainless props on merc B drives in which case you must have given it a very hard knock to bend it significantly in which case I would be checking out the drive and coupler too.

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[Jinks]

Thanks Duncan. It is a stainless steel prop on a Bravo 1 and I was surprised how hard it had to be hit to straighten it but it wasn't so bad that it couldn't be readjusted "manually". I really was doing minimum speed, less than 4 knots - honest.



<hr width=100% size=1>Of all the things I've lost - I miss my mind the most!

 

[greatspirit]

Was that the tidal race off Oxwich point?
Can be very unpleasant on a spring ebb against the wind

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[duncan]

your speed isn't the big thing - it's that the blade must of hit something pretty solidly to do that damage and therefore put quite a shock back through the drivetrain.
However you should have the SS mercruiser coupler shaft on that rig so you can just hope none of the gears in the drive took exception to the 'shock'!
As you can drop the propp off easily enough with the boat int eh water I think I would get it sorted 'midweek', taking it with me when I left and sticking it back the next weekend - but only you can really judge. However if you think it needs doing do it earlier rather than later!
btw what revs do you find your engine running up to?



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[Jinks]

No, just as I reached the Worm from Carmarthen Bay. I was about 2 miles off shore and had a following swell of at least 3 metres. Had the boat on tickover doing about 6 knots until a wave picked me up and accelerated me to about 25 kts. Soon realised there was no point fighting so 'surfed' the wave until it left me behind, dropped back to 6 kts and waited for the next one.

This continued until we reached Mumbles head and turned into the bay. An interesting hour or so.

<hr width=100% size=1>Of all the things I've lost - I miss my mind the most!

 

[Jinks]

Yes Duncan, I suppose I knew that was the sensible thing but was hoping to avoid getting in the water in the marina. Can't reach it from the pontoon because of the swim platform. Is there any way of finding out wether any of the gears did take exception?

Unfortunately, I can't answer your last question. When I bought the boat, it was fitted with a petrol engine tacho which showed either maximum revs or none at all and even that stopped working altogether after about 80 hours. I have been speaking to the Monterey dealers who sold the boat originally. They agree that this is a warranty item and have ordered a replacement for me. I have been waiting for this since June. I've been reading all about engine efficiency and output at different percentages of maximum and am looking forward to experimenting. In the meantime I just drop it back a little from maximum and carry on (conditions permitting of course).

<hr width=100% size=1>Of all the things I've lost - I miss my mind the most!

 

[duncan]

have you tried sticking 4 guys on the bow - this can often allow the drive to stick the prop up out of the water (or close) even when not in trailer position and let you change the prop from the pontoon - works for me.

re revs I look forward to hearing the results with interest - I say this because mine (and others) rev comfortably to the goverened speed (3650) although max power is (one hour rating) 3300 and continuous rating 3100

good luck

<hr width=100% size=1>madesco madidum ..../forums/images/icons/smile.gif

 

[Jinks]

Have you any idea how much beer it would cost me to get four guys to sit on the bow and hurl insults at me while I take the prop off and drop it in the marina? You've been really helpful up to now as well /forums/images/icons/wink.gif.

<hr width=100% size=1>Of all the things I've lost - I miss my mind the most!