Paint coming off props

P

PGD

Well-Known Member
Joined
9 Jul 2001
Messages
1,032
Location
Thames - non tidal
www.peter-davey.com
Had the props reset and repainted by Steel Developments about a month ago and have been down on the tidal Thames for two weeks having a zip about. Props were also lacquered.

Have had to have the boat lifted due to leaking sea cock, boy that’s annoying, 120 quid each way on the lift out and in all for 10 quids worth of gate valve./forums/images/icons/frown.gif

But anyway, had a look at the props and on the inner sides of some of the duo prop blades the paint has come off, looks like someone has been scrubbing them.

Any ideas.

Peter


<hr width=100% size=1>Who gives the best service? tell us <A target="_blank" HREF=http://www.mssa.org.uk>Marine Service Standards Assistance</A>
 
Most likely to be cavitation, almost burns the surface of the prop. Also if the water has a lot of silt that will also speed up the process.

<hr width=100% size=1>
 
One of the reasons for Volvo going over to SS props for higher powered motors 'cos the plastic coating just pinged off under deflection. Only cure is to go SS next time you 'ding' a prop and use your repaired Al as a spare.

<hr width=100% size=1>
 
Def worth spending a bit more and getting rid of the gate valves is favour of the ball valve. It is much less likely to have a problem with a small bit of barnacle. and at £120 each way for the lift is a valid spend to save measure /forums/images/icons/smile.gif

<hr width=100% size=1>
 
Re: Absolutely NOT ball valves!

I have been a trained plumber in my time, Ball valves should never be used under these conditions, it is well known that the ball can wear and come unseated! Gate valves are the correct valve for this type of job. Why do you think all the manufacturers use them?

They should of course be serviced regularly, by spraying WD40 on the thread and also when the boat is out of the water it should be sprayed directly into the valve and the valve operated several times to ensure the oil is lubricating the gate.

Barry


<hr width=100% size=1>I just want to retire with my boat to the Med!
 
In my experience nothing stays on a prop! but you might have helped it come off by touching soft ground without knowing it?

Barry


<hr width=100% size=1>I just want to retire with my boat to the Med!
 
Re: ball valves are good

I accept that some ball valves are not acceptable for marine use, but exactly the same is true of gate valves. Furthermore, when ball valves are no longer closing properly, it is immediately apparent whereas gate valves can have all the appearance of being correctly shut, but arent.

It is no co-incidence that the article on repacing sea cocks in the JUly PBO features the use of ball valves.

As to why a lot (def not all) of manufacturers use gate valves, that is easy, they are cheaper /forums/images/icons/smile.gif

<hr width=100% size=1>
 
hi guys, cheers for the advice, so here is the background info.

Boat is 20 yrs old with original kit on board. Gate valves, ie look like central heating valves, are used on the boat, 3/4" inlet to toilet and 2" outlet with and 1 1/2" valve to change between holding tank and sea outlets.

The change down to 1 1/2 " causes blockages all the time and I wanted to change this, now I have a reason to.

Also the pipes stink, not low / no odour pipe work, so want to change that too.

The gate value on the inlet leaks when open, doesn't when shut. The outlet to sea, hardly used, doesn't close properly and lets air out all the time as the water bubbles even when changed to holding tank.

So the plan, rip the whole lot out, including the toilet and start again, have been advised not to go for electric toilet so will stay with manual, the plan was to change to ball valves so you could easily see if they were open or closed..... forgot to shut the intake when on the tideway and wondered why I had a bowl full of water, then the penny dropped /forums/images/icons/smile.gif.

So I could do with a decisive answers ….balls or gates /forums/images/icons/wink.gif

cheers in advance

Peter


<hr width=100% size=1>Who gives the best service? tell us <A target="_blank" HREF=http://www.mssa.org.uk>Marine Service Standards Assistance</A>
 
Hi deffo not touched ground, alarms would have gone off, only chewed up a few twigs when returning home up river after the storms on Wednesday, thought I'd dinged a prop then but looking at them they are fine, just half the paint missing /forums/images/icons/frown.gif, so will black paint them again and cover in lacquered again.

As has been suggested being on the tideway of the Thames in the muddy brown waters may have “sand blasted” the props which they would not normally get at 4 Knts up river.

Oh well

petet


<hr width=100% size=1>Who gives the best service? tell us <A target="_blank" HREF=http://www.mssa.org.uk>Marine Service Standards Assistance</A>
 
You STILL have blades on your props.

My recent trip,resulted in a lump about 50cms wide going AWOL from one of the blades on my starboard prop.
Somewhere around Tower Bridge there was a rather pronounced thud.

<hr width=100% size=1>There I was,upside down with nothing on the clock....../forums/images/icons/laugh.gif
 
Re: You STILL have blades on your props.

Ow! must say i was a bit worried about chewing something up and as I have duo props it would be expensive.

Is yours repairable?



<hr width=100% size=1>Who gives the best service? tell us <A target="_blank" HREF=http://www.mssa.org.uk>Marine Service Standards Assistance</A>
 
Re: Props.

The prop is off to Steel Dev (again) today.Am thinking of inventing some sort of quick release attachment device.

<hr width=100% size=1>There I was,upside down with nothing on the clock....../forums/images/icons/laugh.gif
 
Re: Props.

Did you have to do a lift out and are you on Legs and can do the job in the water?

<hr width=100% size=1>Who gives the best service? tell us <A target="_blank" HREF=http://www.mssa.org.uk>Marine Service Standards Assistance</A>
 
You must log in or register to reply here.

Share this page

Top