Prop problems

Richard B · 27 October 2003, 22:04

OK - update on the prop situation...

In the botton RH corner of the photo are the bits of rubber which look as if they had melted/worn away from the outside of the rubber bush:

Richard B · 27 October 2003, 22:06

And again from a different angle:

The Jackeens · 27 October 2003, 22:39

a thread that may be of interest along the same
lines
http://www.sterndrive.com/board/show...351&TopicID=42

Richard B · 27 October 2003, 22:41

Paul - it don't work!

Your search - cache:WSDtvVyGFXkJ: - did not match any documents.
No pages were found containing "wsdtvvygfxkj"

OK I registered there now.... what was the thread called?

Ribald · 27 October 2003, 22:52

Richard, I don't suppose you noticed any drop-off in performance during your trip to Alderney & back - could you have snagged a rope/net briefly which would have "snatched" the prop but not got tangled up on same?

Richard B · 27 October 2003, 23:01

No - definitely not. It was quite a trip - I reckon that the prop spent more time out of the water than in it (trying to keep pace with an 8.5 you see

) so unless the fishermen were setting nets for flying fish, I reckon we were well out of their way!

Ribald · 27 October 2003, 23:04

Perhaps that's the answer then - the prop revving nicely when in the air and then dropping back into the (solid) water so often.

Was it a new or s/h prop?

Richard B · 27 October 2003, 23:13

Well, my thoughts entirely. However... We were OK on the way out, maxed 41kts with quite a bit of time airbourne. Return was different altogether... 22-25kts with a lot cannier driving required (Daniel taught me a few things) but the failure happened in flat calm water after a bit of a "breather" rafted to Liquidator to transfer the scruvey crew. Then it all went pear shaped after gentle acceleration to 46kts.

The Jackeens · 27 October 2003, 23:22

Quote:

Originally posted by Richard B
to transfer the scruvey crew.

Steady On I might get the hump.

The link is sorted above.

paul

Richard B · 27 October 2003, 23:30

Quote:

Originally posted by jackeen
I might get the hump...

You mean you're going to buy a Camel RIB???

Ta for the link.

Ribald · 27 October 2003, 23:59

Quote:

You mean you're going to buy a Camel RIB???

Complete with roof rack I hope

Just out of interest have you ever seen one of these being trailed on the road - saw one a while ago - bl**dy massive

- almost the height of a s/d bus. Not for the faint hearted or low bridges.

Richard B · 28 October 2003, 00:02

Double, surely!

Also, spotted one out on S'hampton Water a few weeks ago - full canvas! Like a trailer tent, had side covers attached to the frame. Probably quite nice and warm in this weather though. I'd have jumped into it without question on Saturday night when we had the brass monkey on board.

Hey Peter, what's wrong with the PPC forum? we registered in good faith but find that we can't post

All the threads appear to be "closed" and we've been on our best behaviour! Is it because those guys winterise their boats at the end of September and go into hibernation until next June?

Or is it a hint that we oughta join?!?

Daniel · 28 October 2003, 22:17

Just got back for working hard for a few days

not something i enjoy.

Anyway, Richard, mentioned our 'situation' on Saturday to my local Marine guy who knows everything, and he almost brushed off the occurance with a comment like "Oh, you blew the bush then" as if this is normal!

Naturally his attitude changed when i told him prop was under a week old and had done about 5-6hrs work! I never even knew this was possiable - should we be checking our props, especially on older engines?

Will enquire more tommorow and let you know. Keep me posted how you are getting on (PM me if you don't want to divulge everything to the world here!)

Julian

Next trip might involve my new boat, but i'd be leagues behind you @ 27knts and Richard @ 22-24 knts in that sea i think.

Richard B · 28 October 2003, 22:28

Quote:

Originally posted by Daniel
should we be checking our props?

The answer to that is yes - especially if you've bought a Solas prop, or had a prop re-bushed by Steel Developments, or if your engine's over 130hp. 3 out of 3 for me, as it happens. I shall explain, but first a picture of the repaired prop (don't know if you'll see much difference...)

Richard B · 28 October 2003, 23:37

OK - here's the explanation, and the full story behind the prop, no names apart from the manufacturer and supplier as that's completely relevant.

Start at RIBex2002 and the owner of a reputable South Coast RIB charter company buys a new Solas prop from the Steel Developments stand. First time out on the water, he suffers the same fate as me but within 30 mins. High profile corporate charter abandoned, prop returned to Steel Developments for replacement, with apologies and assurances that this a very rare event. But boat sold before it can be re-fitted.

September 2003 and yours truly buys the replacement prop (at bargain price!) from the reputable charter company and fits it to my RIB. Fails after a cross-channel trip, and I look around for a prop repairer I can trust.

Spoke to a chap recommended by forum members whose first comment is "Bushings on Solas props for big motors aren't up to the job". UhOh!

I took the prop in for repair this morning and wow, what an eye-opener! First thing is that the prop appears not to be a "new" prop, but a repaired unit. Not the fault of the charter company I hasten to add, as he is as much the victim as me in this episode. Rubber bush removed and compared with stock bushes. The bush fitted is not a heavy duty unit, but only suitable for engines up to 130hp. I compare medium duty (up to 130hp) bushes and heavy duty bushes (130-250hp) and there's quite a difference in construction and material. More on this later.

My trusted repairer then fits a new heavy duty bushing, using a hydraulic press and lubricating the bushing with a special rubber lubricant (not fairy liquid or swarfega) which will both harden with age and then dissolve in water. Because of this, new props should be run at tickover only for the first 20 mins use to eliminate any slip.

Here's a picture of the offending bushing, deformed after being subjected to torque outside its design spec and polished from slippage.

Richard B · 28 October 2003, 23:48

These bushings are a rubber compound mounted on a bronze shaft. The higher the engine power, the thicker the bronze shaft should be, and the harder the rubber. The bronze shaft on the medium duty (up to 130hp) is about 5mm at rear of the shaft, and for the heavy duty (130 - 250hp) is about 10mm at rear of the shaft. The picture should show this - on the left is the old bushing and on the right the new one mounted in the prop:

Richard B · 28 October 2003, 23:53

So, in conclusion Steel Developments are not flavour of the month for me. In fact I've a few choice phrases for them.

If you want a good prop repairer, drop me a PM or email.

Thanks to Pete7 and Jackeen for their assistance in getting this sorted.

Dirk Diggler · 29 October 2003, 08:35

Quote:

Originally posted by Richard B
If you want a good prop repairer, drop me a PM or email.

Is it a secret then that you don't want to share with everyone.

I've always used Prop Revs in Poole, very experienced with high perf props, alway I've only ever heard good things about Steel Developments.

Perhaps we need to hear the other side of the story from them.
I've always found that their is no substitute for quality, and I can't understand why anyone would buy what is a cheap prop to use in a "high perf" installation. The props that both Yam & Merc supply may not be cheap, but they are excellent.

However, prop failure is quite often caused by pilot error, perhaps you need to understand how to throttle a boat in rough conditions. Maybe you should take advantage of some of the excellent RYA approved courses that are available in your boating area!

Your never to old to learn!!!!

Julian · 29 October 2003, 08:59

Dirk

I dont believe it was pilot error that caused Richards prop to let go. We the same problem on our 200 Mariner a few years back and it was down to a worn bush as with Richards it was not the right one for the job. To maintain 22 -24 knots in the sea conditions we encountered showed that Richard was driving the boat well otherwise he would have been down to about 10 knots.

Julian

Charles · 29 October 2003, 09:03

Quote:

Originally posted by Dirk Diggler

However, prop failure is quite often caused by pilot error, perhaps you need to understand how to throttle a boat in rough conditions. Maybe you should take advantage of some of the excellent RYA approved courses that are available in your boating area!

Your never to old to learn!!!!

Bullsh*t - bushes fail - end of story!