Wow, Rafiki has lost 10 kn in 6 weeks due to fouling!

rafiki_

rafiki_

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Had what should have been a quick blast over to Penarth last evening, except it wasn't so quick. We could only make 17kn, against the 27 last time out. A friends boat did just the same.

The crossing was really quite unpleasant, quite a strong wind over tide.

Reports in our marina are that they have never seen such growth as this summer :(
 
We've lost 5knts. The fouling on the legs is horrendous with tiny barnacles which we don't normally have a problem with. Just spent the last hour pressure washing as best we could on the berth.
L
:)
 
Is this something that affects legs more than shafts? Being first year in the Solent I was expected to lose a few knots (a couple of friends said I would). In fact I thought I was until I realised it's the log that's under-reading whereas the GPS shows (accounting for tide) that we're still pretty close to our 20knots cruising.
 
It certainly affects fast planing boats more than 20 knot boats and more than displacement boats, what is scary is what it does to your MPG which rockets.

MBM took a boat that had been in the water for 12 months it was a 42ft mobo and at cruising speed it lost 3.3knots the MPG increased by 29%.

I would say on a fast planing boat with say a clean cruise speed of 27 knots the fuel burn as MPG would probably increase by considerably more northwards of 40%.

A mid season lift and pressure wash makes a considerable difference in fuel burn.
 
rafiki_ said:
Had what should have been a quick blast over to Penarth last evening, except it wasn't so quick. We could only make 17kn, against the 27 last time out. A friends boat did just the same.

The crossing was really quite unpleasant, quite a strong wind over tide.

Reports in our marina are that they have never seen such growth as this summer :(
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which marina?
 
Legs have Trilux, fouling is about the same as last season in Brixham.

Guess the good weather has played its part. Shame sealift is no longer in east Cowes , can't justify £400 odd for a mid season lift and scrub
 
I also increased my fuel consumption by 30% & speed down by 6.5 knots & it wasn't that badly fouled.Pressure wash & a bit of scrubbing/sanding the props brought it back to health.Lesson learnt.That was East coast river & took about 12 weeks
 
Ha, ha, Med boating arrives in Penarth! Its fairly typical for us Med boaters to lose several knots in a few weeks due to sterngear fouling. In fact one boat I had in Palma wouldn't actually plane after 3 months of summer fouling. Is this due to global warming (ducks for cover!) or some kind of water pollution?
 
Deleted User said:
Ha, ha, Med boating arrives in Penarth! Its fairly typical for us Med boaters to lose several knots in a few weeks due to sterngear fouling. In fact one boat I had in Palma wouldn't actually plane after 3 months of summer fouling. Is this due to global warming (ducks for cover!) or some kind of water pollution?
Click to expand...

Hmmmmm, doesn't feel very warm here today! Have been watching the Extreme Cat racing in Cardiff Bay. Fantastic spectacle. Will post some pics when I get home early next week.

Actually, I think the warm spell we had in July accelerated the fouling. Cooled down a lot now.
 
Hmm , odd, been boating in the med(mallorca) now for 8 years , no loss of speed at all throughout the season. Boat is in the water 365 days of the year,no mid season lift out required, just once every 12 months .
 
It's the worst I have seen it this year by miles!! 1 week after my boat was scrubbed the legs were covered in growth!
 
Just out of curiosity if your losing knots at planning speed are your engines making the normal revs or are they getting to a rev point and just stay there regardless of adding more throttle

Thanks
 
Gemini said:
Just out of curiosity if your losing knots at planning speed are your engines making the normal revs or are they getting to a rev point and just stay there regardless of adding more throttle

Thanks
Click to expand...

They would only pull just over 2000 rpm, normally they will run up to 2800.
 
julians said:
Hmm , odd, been boating in the med(mallorca) now for 8 years , no loss of speed at all throughout the season. Boat is in the water 365 days of the year,no mid season lift out required, just once every 12 months .
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Where are you based because I reckon we all want to base our boats there? I've had boats based in SoF, Costa Blanca, Majorca, Croatia and now, Italy and without exception, the sterngear gets fouled in only a few weeks in the water and speed/rpm is lost. Have you got sterndrives or outboard engines on your boat and do you lift the props clear of the water when you leave the boat?
 
rafiki_ said:
We could only make 17kn, against the 27 last time out. A friends boat did just the same.
Click to expand...
Both wrong boats, I reckon.
Mine doesn't struggle at all to make her usual 8 to 9 kts cruising speed, through the whole season! :D
 
We lost 12 knots after a few weeks due to the Weymouth worm and barnacles covering the props. Fresh water flows into Weymouth harbour and I believe the combination with seawater gives particularly adverse conditions for fouling.
A couple of years ago speed would not exceed 10 knots despite antifouling etc in March and after flogging along for a short time at WOT the engine temperature alarm went off but no harm done. Again this was fouling on the props.
I had fitted an ultrasonic antifouling system to the hull that does some good. On lift out at Portland marina it had a coating of slime and the log had stopped working however I suspect that if I could have got up some speed it may have self cleaned a little. The shocker was the state of the props!
Would shaft drive props be less prone to fouling than sterndrive?
 
It has been bad this year. Tk on the props failed and they were barnacled up. So were the trim tabs, shafts, p brackets and bow thruster.
The Coppercoat had a thicker layer of slime than I've seen too.
I dived about 4 weeks ago and removed all the barnacles. But before a france trip i decided on a lift and hold to get rid of the slime. The props were 1/3 barnacled again.

Anyway, shaft boats dont get the props fouled quite as easily, but they do foul. And i cant clean them lying face down on the pontoon with the legs raised.
 
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