My boat (H466) was kept in all winter. Had a diver scrub the bottom recently and from the dock it looks black like it should. BUT...slow boat now. Last year with a clean bottom after launch, 7.8 kn easy. Now, 6.5 is the best I can do under power. I can't imagine anything else slowing the boat down. Leaving on vacation in a few weeks and considering haul and power wash for speed. QUESTION: Anyone have experience with diver clean vs. haul and power wash and the effect on speed?
Power wash vs diver scrub on speed
- Thread starter drchpete
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My boat stays in the water all year round. Using a diver I go 3 + years between haul outs. I usually do it when the diver says I need a bottom job. I make a point of being around to see her come out of the water and have always been pleased at how clean she is, just the anti fouling is getting thin in places.
A good diver would tell you when he could not do an effective job. Otherwise it should be as good as if it had been hauled out.
A good diver would tell you when he could not do an effective job. Otherwise it should be as good as if it had been hauled out.
Prop
Was the prop cleaned real good and when was the last time you checked your mixing elbo,are the RPM's reaching the same.
Nick
Was the prop cleaned real good and when was the last time you checked your mixing elbo,are the RPM's reaching the same.
Nick
RPM's are fine running at 2700 - 3000 which is what I always do. Keeps the temp at 180-190 which it always has. I changed the antifreeze this spring but that can’t have any effect. Nothing else is different. Same load same everything, just a lot slower. I can't come up with any reason other than the bottom.
Re: Prop
just checked the prop, it's pretty clean. Bottom already has some algae on it but very thin film.
just checked the prop, it's pretty clean. Bottom already has some algae on it but very thin film.
A thorough cleaning is a thorough cleaning regardless of whether it happens in the yard or in the water. The end result is the same. Are you confident the diver cleaned the entire hull?
Yes, I think the hull looks clean. It's black which is the color of the paint. How else can I judge it? I can't get under there and check the entire hull or I'd do the job myself. All I can do is hold my breath for 30 sec or so and take a peek. 466 is a big hull. Is it possible the paint being it water for a year just has a rough surface creating drag? Only 2 things in this equation. Power output (which looks fine) and Drag.
I did check the speed via GPS SOG and it coincides so it's not the wheel which I cleaned prior. Seriously considering haul-out wash and paint.
Haul out vs diver cleaning
The economics are, diver cleaning costs about $400 per year, for which we keep a clean bottom, clean prop and get zincs changed (if needed) and some inspections and feed back e.g. cutless bearing check. That puts off a haul out for 2 years or more. I am currently at 4 years since the last haul out.
Maybe the fact that I take my boat into fresh water from time to time also has some benefit as it is probably very upsetting to some of the growth. Whenever I do I take advantage of the fact that the water is 20 deg warmer than the bay and dive under myself for a look around.
If you are going to haul out I suggest you be on hand to see what she looks like when she comes out.
Realy there is nothing magic about a haul out clean vs. diver clean. The divers efforts make a big difference, even after just 3 months, but as long as the anti foul has not reached the point where he can't keep ahead of it we don't haul out.
The economics are, diver cleaning costs about $400 per year, for which we keep a clean bottom, clean prop and get zincs changed (if needed) and some inspections and feed back e.g. cutless bearing check. That puts off a haul out for 2 years or more. I am currently at 4 years since the last haul out.
Maybe the fact that I take my boat into fresh water from time to time also has some benefit as it is probably very upsetting to some of the growth. Whenever I do I take advantage of the fact that the water is 20 deg warmer than the bay and dive under myself for a look around.
If you are going to haul out I suggest you be on hand to see what she looks like when she comes out.
Anyone know what the diver actually does to clean the hull? I was SCUBA-certified many years ago and, although it's been a few years since my last dive, I am/was planning to clean the hull myself every year. I assumed a plastic scraper and stiff brush would be the primary tools needed, but am now wondering what actual tools might be used, and how much time and effort would be required.
Thanks!
Thanks!
Watch a hull cleaner at work (cleaning a Hunter, BTW):
https://www.youtube.com/watch?v=qzawnxVPlL0
https://www.youtube.com/watch?v=kgPmXg1-o5g
I have a 466 that is always in the water. It is scrubbed by a diver about once a year and hauled every 3 years. All I can add to this discussion is perhaps the diver missed some growth on the very bottom of the keel. That is prone to get some growth as it is usually the last portion of the boat to get painted, if at all. One year I had what I thought was a very clean hull (BTW, I see no difference between a diver or haul cleaning) and there was a section about a foot long and the width of the keel with some seaweed about three feet long. Geez. Must have been similar to dragging a 5 gal bucket. When I cleaned that off I gained .2-.3 kts.
Wash and paint clearly superior
Pursuant to the above comments by myself and others, I now can confirm that the haul, wash and paint is superior. Frustrated with the loss of speed I had the boat hauled, washed and painted after one year in the water and a diver scrub. The hull looked pretty clean when hauled with the beginnings of a super thin slime layer in some areas but no weeds, The prop had no barnacles but there was a little thin crust in some areas of it.
Results:
Before haul, 5.6 cruise and 6.3 max with all water tanks empty.
AFTER haul, wash, paint, 7.3 cruise and 7.7 max and that's AFTER taking on 200 gallons of water and 50 gallons of deisel plus a family of 6 with gear just before a cruise so it woudl have been faster without all this extra weight.
Conclusion: These are objective physical findings which are measurable and not asumed or guessed at. I can't argue with the results. Haul wash paint is clearly superior to diver scrub. No offense to the divers out there, they do a great job but the results are what they are.
Pursuant to the above comments by myself and others, I now can confirm that the haul, wash and paint is superior. Frustrated with the loss of speed I had the boat hauled, washed and painted after one year in the water and a diver scrub. The hull looked pretty clean when hauled with the beginnings of a super thin slime layer in some areas but no weeds, The prop had no barnacles but there was a little thin crust in some areas of it.
Results:
Before haul, 5.6 cruise and 6.3 max with all water tanks empty.
AFTER haul, wash, paint, 7.3 cruise and 7.7 max and that's AFTER taking on 200 gallons of water and 50 gallons of deisel plus a family of 6 with gear just before a cruise so it woudl have been faster without all this extra weight.
Conclusion: These are objective physical findings which are measurable and not asumed or guessed at. I can't argue with the results. Haul wash paint is clearly superior to diver scrub. No offense to the divers out there, they do a great job but the results are what they are.
Is a brand spanking new bottom (not part of your initial inquiry, BTW) preferable to an old one with an indeterminate amount of fouling scrubbed by a diver who may, or may not have done a good job? I guess so. But that's all you've shown here. You certainly cannot make a blanket statement about hull cleaners based on this flawed experiment and your experience with a single diver.
Perhaps you're right, a fresh coat of paint is not an exact comparison vs. scrub. Scrub vs. power wash is more fair. But if one has paid for a haul you might as well paint. So I guess what I should say is a haul wash and PAINT is going to be faster than a scrub. There is no arguing this. My scrub speed was 5.6, my paint speed was 7.3 and I was carrying 2065 lbs. (the math is correct) of fluid more + gear when I did the 7.3. So I guess the only way to really answer my original question would be to wash and not paint but that's unrealistic. The bottom line is that the scrub cannot bring a year-in-the-water boat back up to speed. It cannot according to this "experiment".
"Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passion, they cannot alter the state of facts and evidence." - John Adams
"Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passion, they cannot alter the state of facts and evidence." - John Adams
Sure, a haul, power wash and new paint will always outperform a diver's scrub at the end of the useful life of the paint. fstbttms has repeatedly pointed out on this and other forums that paint has essentially a shelf life, regardless of how good the paint "looks" its chemicals only last so long.
My experience is that within the useful life of the paint, after a diver does his thing, I'm just as fast as right after we have a paint job. As the paint ages, once past its useful life of two to three years, only a new paint job will restore the speed.
You're right, one HAS to compare apples to apples.
My experience is that within the useful life of the paint, after a diver does his thing, I'm just as fast as right after we have a paint job. As the paint ages, once past its useful life of two to three years, only a new paint job will restore the speed.
You're right, one HAS to compare apples to apples.
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