Boat speed decreased by 1 knot
- Thread starter mytime
- Start date
fstbttms: My boat does not grow any of that stuff. I said just slime, which is only about 1" fine thickness. By the time it dries it is basically just the ablative paint with a loose powder like stuff on it. If I had any of that growth I definitely would clean it! Chief
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This is a Sabre 402 at a brokerage in Alameda. I assume that it has not left the slip in that time.
Why do you need to be a "Anode expert" to be a competent sailor?
The following is a cut and paste written by a New Zealand sailor and electrical engineer:
"It could also be that, in some cases, overdoing the number of anodes may encourage bronze parts to foul up with marine growths:
George Taylor (retired editor of the magazine 'Practical Boat Owner' observes that bronze cannons from ancient warships are often recovered after centuries of submersion in excellent condition and free from marine growth. However when bronze propellers are protected by large numbers of zincs, they frequently grow large amounts of weed and barnacles. If anodes are not used propellers can rot away but remain clear of marine growths.
The most likely explanation for this is that when left to its own devices a small amount of copper is leached from the bronze which discourages marine growths. By using large amounts of zinc, this leaching is reduced and so barnacles, weeds etc. can take hold, but there is a delicate balance to be obtained between using just enough anodes to balance out any corrosion currents without blanking off just sufficient copper release to deter fouling."
"It could also be that, in some cases, overdoing the number of anodes may encourage bronze parts to foul up with marine growths:
George Taylor (retired editor of the magazine 'Practical Boat Owner' observes that bronze cannons from ancient warships are often recovered after centuries of submersion in excellent condition and free from marine growth. However when bronze propellers are protected by large numbers of zincs, they frequently grow large amounts of weed and barnacles. If anodes are not used propellers can rot away but remain clear of marine growths.
The most likely explanation for this is that when left to its own devices a small amount of copper is leached from the bronze which discourages marine growths. By using large amounts of zinc, this leaching is reduced and so barnacles, weeds etc. can take hold, but there is a delicate balance to be obtained between using just enough anodes to balance out any corrosion currents without blanking off just sufficient copper release to deter fouling."
mytime: not knowing basic concepts for anode use can result in high bucks mistakes. Thats far from an "anode expert".
All you need to know is provided for you by post #11, fstbottms. Copy it. Chief
All you need to know is provided for you by post #11, fstbottms. Copy it. Chief
Ablative paints are often slower than hard, so that might explain the speed difference.
As for the use of zinc vs Al or Mg in brackish or fresh water - isn't zinc still less noble than what needs to be protected? So if there's not enough corrosive effect to deteriorate the zinc before it self-insulates, then why would other underwater metals be at risk? (Ignoring the possibility that you deactivate the zinc then travel somewhere more corrosive).
Calm down, I was replying to Scott, who said he's going slower, but didn't specify by how much. I agree it shouldn't be the cause for the OP losing a full knot.Really? 15-20% slower? Give me a break.
A ridiculous assertion that ablative paint is slower than hard all else being equal? Someone should tell all of the racers who use VC17 and hard epoxy based paints rather than ablatives. Also someone should tell that to Interlux, who states - "The club racer is usually better off with a higher level of antifouling protection offered by a Micron® product, while Grand Prix level racers prefer the hard and slick surface provided by a VC® product or Baltoplate". (http://www.yachtpaint.com/literaturecentre/winning_boat_concepts.pdf). While they don't quantify the difference, I'd hardly say such an assertion is ridiculous.
All else is not equal. The reason racers like a paint like Baltoplate is because it can burnished to an extremely smooth finish, which is not the case with an ablative paint. Hard paints are not by nature faster than ablatives.
To make a blanket statement that a 20% difference in speed is attributable to anti fouling paint type is absolutely ridiculous.
To make a blanket statement that a 20% difference in speed is attributable to anti fouling paint type is absolutely ridiculous.