BartW
Well-Known Member
Well thats a very generous offer J,
I'll be at the boat tomorrow (by car) and will think about it,
but perhaps its all too tight, boat goes back in on 18/6
prop pitting, repair or not ?
- Thread starter BartW
- Start date
Well thats a very generous offer J,
I'll be at the boat tomorrow (by car) and will think about it,
but perhaps its all too tight, boat goes back in on 18/6
Ripster
Well-Known Member
I have used Hamble Props several times in the past to cure exactly this type of problem and fill the holes with weld. From memory, the last pair of bronze 22" props they did were about 400 quid all in about 2 years ago. That included re-profiling the blade ends too.
jimmy_the_builder
Well-Known Member
Hi Bart, it's not my car!
It's another member of the PV posse. I don't know the exact timings, but if you think it might help, I can find out.Cheers
Jimmy
Bandit
Well-Known Member
Bart
Providing the props are not going pink ie electrolytic action and starting to show scales you should be OK.
The holes look like cavitation on the root of the blade near to the boss of the prop, classic cavitation.
I understand that you generally run fairly slow due to price of fuel?
Have these holes got any larger in the last year.
Have you got rope cutters with a fixed blade in front of the holes or are the holes on all blades?
I used to operate hydrofoils, 35 knots with props in 1.5metres of water and in disturbed water ie behind the after foil.
We used to get horrendous cavitation on props especially on the last hydrofoil which was the largest and the fastest a prop would last 450 running hours before we gouged out the blade root cavitation and filled in with bronze weld then balanced by hand. With repaired props we found we had a higher incidence of loosing a blade and the boat being out of service . In the end we ran the props way past the repairable point and scrapped them at 850 hours, we suffered less failures and less down time.
We even tried props with two holes through the blade route to avoid cavitation and the worked slightly better.
To be honest the cavitation does not look that bad , not bad enough to cause a failure so repair would be largely cosmetic and will improve the looks of the prop but not its strength.
Euro 2000 per prop for a repair is taking the piss cost wise.
If it was me I would get the pitch and diameter details as well as the name of the manufacturer off the prop as well as to measure the taper and keyway details and get a price for a new set , sometimes you can get a serial number off the prop often on the face of the boss if you get the manufacturers details with serial no they can trace their records to match them
I would then consider getting a new set as spares and when the existing props are badly cavitated or one failed you can change them and keep old props as spares.
what size props are they ?
Providing the props are not going pink ie electrolytic action and starting to show scales you should be OK.
The holes look like cavitation on the root of the blade near to the boss of the prop, classic cavitation.
I understand that you generally run fairly slow due to price of fuel?
Have these holes got any larger in the last year.
Have you got rope cutters with a fixed blade in front of the holes or are the holes on all blades?
I used to operate hydrofoils, 35 knots with props in 1.5metres of water and in disturbed water ie behind the after foil.
We used to get horrendous cavitation on props especially on the last hydrofoil which was the largest and the fastest a prop would last 450 running hours before we gouged out the blade root cavitation and filled in with bronze weld then balanced by hand. With repaired props we found we had a higher incidence of loosing a blade and the boat being out of service . In the end we ran the props way past the repairable point and scrapped them at 850 hours, we suffered less failures and less down time.
We even tried props with two holes through the blade route to avoid cavitation and the worked slightly better.
To be honest the cavitation does not look that bad , not bad enough to cause a failure so repair would be largely cosmetic and will improve the looks of the prop but not its strength.
Euro 2000 per prop for a repair is taking the piss cost wise.
If it was me I would get the pitch and diameter details as well as the name of the manufacturer off the prop as well as to measure the taper and keyway details and get a price for a new set , sometimes you can get a serial number off the prop often on the face of the boss if you get the manufacturers details with serial no they can trace their records to match them
I would then consider getting a new set as spares and when the existing props are badly cavitated or one failed you can change them and keep old props as spares.
what size props are they ?
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BartW
Well-Known Member
A week ago I was able to take the props off,
and bring them with me in the car, and then to a service co in Holland.
last friday one of my guy's picked them up, and during the weekend another friend came down and brought them with him
I had to purchase a new big spanner size 85,
and the props were repaired, ballanced, and polished at a fraction of the SOF inflated prices.
thank you all for advice, comments and proposal for assitance, much apreciated !
and bring them with me in the car, and then to a service co in Holland.
last friday one of my guy's picked them up, and during the weekend another friend came down and brought them with him
I had to purchase a new big spanner size 85,
and the props were repaired, ballanced, and polished at a fraction of the SOF inflated prices.
thank you all for advice, comments and proposal for assitance, much apreciated !
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jfm
Well-Known Member
Nice job! And I love the spanner 
What size are the props btw?
How is the shipyard work going generally? Stabilisers?
What size are the props btw?
How is the shipyard work going generally? Stabilisers?
Portofino
Well-Known Member
Silly Q ? But is there a way of telling which is left or right before fitting ?
Looks good by rhe way
I think the French ( marine tradesmen) generally try it on with repairs .
More people are now not accepting the local " quote " and finding alternative solutions .
But I think it's the law of demishing returns - less viable foreign boaters so they increase the price to somewhat compensate .
It does not work cos we find alternative - homegrown solutions .
Well done Bart .
Looks good by rhe way
I think the French ( marine tradesmen) generally try it on with repairs .
More people are now not accepting the local " quote " and finding alternative solutions .
But I think it's the law of demishing returns - less viable foreign boaters so they increase the price to somewhat compensate .
It does not work cos we find alternative - homegrown solutions .
Well done Bart .
BartW
Well-Known Member
there was a number on the props,
810 970
diameter is approx 81cm,
so I assume 970 is pitch ?
do you want to know gear ratio or are they all the same ?
shipyard generally is good, almost finished works, including sand blasting of the hull
but GRP subcontracter started too late, they are half way now, outside GRP work is finished, now the inside part.
luckyly I planned for some extra delay for the work,
me and my guy's finished the wiring about a week ago,
so allmost ready to fit a pair of stabs
I'm here now almost 3 weeks in Sanary sur mer (with a few interruptions)
one of the nices villages in the area imho.
so very "special" feeling, lots of exitement and discussions with the work on one hand, and a pre-holliday athmosphere on the other hand.
will post updates later
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BartW
Well-Known Member
well I know how the props have to turn, so quite easy to know which is L&R.
and my friend wrote P and SB on them, so absolutely no problem.
don't tell me about the french marine tradesman, this whole sof boat business is completely opportunity driven,
at least the yard here knows and experienced they can't ripp me off. (re props service)
they nevertheless thread me respectfull, considering the stab work that I have to manage myself with the subcontracter,
(very little to none input from them, but they are nevertheless helpfull and friendly)
today another story with water maker service from SOF guy, (will make another thread about that)
sarabande
Well-Known Member
Bart
a couple of questions if I may pls.
1 Did the repair shop offer any comments as the cause - cavitation / casting flaw ?
2 How are the big nuts held on ? locking tabs / split pin / adhesive
TIA
a couple of questions if I may pls.
1 Did the repair shop offer any comments as the cause - cavitation / casting flaw ?
2 How are the big nuts held on ? locking tabs / split pin / adhesive
TIA
BartW
Well-Known Member
they told me that:
- the material the props are made off is old, not used today anymore (I forgot the name)
- the cavitation holes were old, might have been there for several years,
- they didn't tell me exactly why, but cavitation on props seems to happen frequently in that area of the hub, and sometimes with more disaster consequences...
- the big nuts where very easy to take off, there is a security M6 bolt in the border (will post a pic later)
but the prop was more difficult, we had a very big pulley puller to take it off, but that didn't work, (so much force that we were afraid damaging the puller or the prop)
so I went to the DIY shop to buy a gas burner torch (to fit on my campinggas tank) and after a few minutes heating the prop hub, it fell off (approx 50...60 kilos !!!)
we did this work during the weekend while the yard was closed.
rafiki_
Well-Known Member
Good result with the props Bart. Look great now. Good luck with the water maker. I have no experience of these, so cannot comment, sorry.