Happiness Is a Clean Bottom

[Beenjammin]

Thanks i2f, Donradcliffe,fstbttms, & healer.

And thanks again Minggat....you are of course correct about the hard growth if I inverted it. Maybe if I painted it with antifoul?

For clarification...you said it wasnt cost effective..what did you factor in as the potential savings? Anodes? Antifoul? Lifts? Or just scrubbing the greenery away from the waterline?

Thanks again!

[mbianka]

Wish I had one when my boat spent a little over a month here on the mooring while I did some refitting work. Maybe then I would not have had to deal with this:
THE BIANKA LOG BLOG: JUST SCRAPPING BY

Capt. Mike

[Minggat]

Wow Mbianka !!! Don't know where you are, but I'm thinking that's a lot of critters for 1 month !!

Beenjammin,

Sorry. It's been many years and brain cells ago. I'll throw in a couple of thoughts though.

Cost of unit- vs- cost of antifouling, lift, diver for monthly scrubbing. Anodes,... the jury is still out on anodes. In the end, you only get about 5 years out of it. If you have to haul out for any other reason, the cost of that could be weighed against the cost of the unit.

Painting it with antifouling to make inverting it would be a cost to figure in. Then bear in mind that WITH antifouling paint already on the bottom of a boat, you still need a diver to clean the bottom from time to time. In my corner of the world, that's once a month. And cleaning the bottom of something.. less than rigid... (you push against it, it moves away)... Nothing sounds good about that.

After all of that, if you leave your slip for a week or 3, without bottom paint, you might have growth. If you bottom paint AND buy one of these,...

I'm getting a headach. Please don't make me think.

Like I said. In my former marina, you would see them on weekender powerboats only. And I talked to a diver who made money off of boats that needed work below the waterline because the owners fell for the "preserves the zincs" line.

[mbianka]

Minggat:

I'm in the Northeast U.S. Yes, I was surprised at the amount of growth too. But, the waters this summer are really warm and the marine organisms love it as much as I do. Now I plan too to keep the boat moving more now that my work on the new dodger is done.

Capt. Mike
THE BIANKA LOG BLOG

[Beenjammin]

Thanks again Minggat, and apologies for the headache!

I got a quote for one of these things at AUD$3700. Over 5 years thats AUD$740 per annum. For that kind of dough I can get her lifted and pressure cleaned 3 times a year. Think I'll spend the money on dive lessons, some scuba gear and a stiff brush instead.

OK next question folks, and a real newbie owner one......for a GRP production boat with a fin racing keel, LWL 41.5 feet, beam 13 feet, draft 6 feet, roughly how many days would it take 1 keen sailor, armed with a power sander, to prep and paint her nether regions with antifoul? (assuming good weather...we always have good weather in Queensland!

[Minggat]

Aarrrrgg. I don't remember a price like that. Good choice to move along from that one.

Pretty big boat for a "real newbie'.

I'd start a new thread with that question. As for me, it would take years to do that job. (too far from my boat now)

[gandalf]

Are you removing all the antifouling back to the gelcoat? If so, the time would depend on the thickness, whether or not you're allowed to dry-sand (not recommended) or if you're going to use a scraper to remove the old stuff. If you're just going to give it a scuff-up you could knock it off in a couple of days, cleaning the surface with a scourer and water before overcoating with antifouling.

I've just done the same thing the hard way, removing all the anti-fouling, then sanding the gelcoat to investigate the blistering problem, before planing the hull to a depth of 2.5mm to remove all the problem material before reglassing and epoxying. So far to the planed and sanded stage I've spent about 10 full days on it. But then again, I'm somewhat of a slow learner!

[Beenjammin]

Thanks Minggat. Newbie Owner more than Newbie Sailor.

Gandalf (youve gotta be worth listening too with a name like that): No I'll just be wet sanding back the existing ablative paint to scuff it up. Im wondering if I'll be cursing myself for attempting to single handedly antifoul a 43 footer and if I should just bite the bullet and pay the $1800 for a pro job. Believe me I have better things to spend money on right now with this baby. A couple of days doesnt sound too bad.....anyway Ill see during the survey if theres any osmosis which will definitley mean paying the pros. Otherwise I might have a crack at it unless anyone out there has words of caution for me to consider, which Id very much appreciate.

I might follow Minggats suggestion and move this issue to a new thread.

[boatbag]

Ps you may be able to scrub your antifoul off - (probably against the law) but more often than not the big problem is shells growing on props and getting into your cooling system. this will run into BIG $$$$$. not to mention bellows and seals...a Bertram owner in Sydney recently paid a large amount to have his bellows redone. Having used boatbags in the past he purchased one for his new 25 Bertram and installed it before leaving for a 1 month trip to California. Just thought I would share this story with you.

[model 10]

OK next question folks, and a real newbie owner one......for a GRP production boat with a fin racing keel, LWL 41.5 feet, beam 13 feet, draft 6 feet, roughly how many days would it take 1 keen sailor, armed with a power sander, to prep and paint her nether regions with antifoul? (assuming good weather...we always have good weather in Queensland![/QUOTE]


Depends, if you use a littlle girliy sander, days and days. If you man up and use a 7" job with 36 grit, 2-3 days.

[donradcliffe]

Originally Posted by Beenjammin

Thanks again Minggat, and apologies for the headache!

I got a quote for one of these things at AUD$3700. Over 5 years thats AUD$740 per annum. For that kind of dough I can get her lifted and pressure cleaned 3 times a year. Think I'll spend the money on dive lessons, some scuba gear and a stiff brush instead.

OK next question folks, and a real newbie owner one......for a GRP production boat with a fin racing keel, LWL 41.5 feet, beam 13 feet, draft 6 feet, roughly how many days would it take 1 keen sailor, armed with a power sander, to prep and paint her nether regions with antifoul? (assuming good weather...we always have good weather in Queensland!

Depends on what condition the bottom is currently in. If its ablative paint with no significant buildup and no flaking, one day for a light sand and one long day for rolling 2 coats. If its harder paint and you need to take it down to bare fiberglass, figure 2-4 hard days work for the prep, assuming you are capable of holding a sander over your head for hours at a time. You can use 36 grit and a 7" softpad sander if you know what you are doing, but 60 grit on a 5" random orbital is easier to control and keep fair, even if it takes 50% longer.

[boatbag]

Hi - having done this type of work on 26- 66 feet of boat 2-3 days seems ambitious. there is a lot of ground to cover and painting on your own - including moving gear to stand on to reach (safely) is hard going. Not sure how fit you are but holding a grinder at or above your shoulders is no mean feat. I also recommend getting a vacumn extraction sander.

Antifoul is highly toxic stuff!!!!!!!!

[Seaworthy Lass]

Originally Posted by donradcliffe

Depends on what condition the bottom is currently in. If its ablative paint with no significant buildup and no flaking, one day for a light sand and one long day for rolling 2 coats. If its harder paint and you need to take it down to bare fiberglass, figure 2-4 hard days work for the prep, assuming you are capable of holding a sander over your head for hours at a time. You can use 36 grit and a 7" softpad sander if you know what you are doing, but 60 grit on a 5" random orbital is easier to control and keep fair, even if it takes 50% longer.

This is an old thread and the OP hasn't posted for a couple of years, but clean bottoms are always of interest .

A word of caution - International state the following:
Antifoulings should only be wet sanded. Never dry sand or burn off antifoulings.

Antifouling is toxic both inhaled and absorbed through the skin, and unless extreme precautions are taken with cover up gear and breathing apparatus, exposure is unavoidable when dry sanding.

If a significant amount of old antifouling is still left then the active ingredients leach into this and the new antifouling is less effective, hence there is an advantage to getting as much of the old stuff off as possible. This would be of lesser importance if you haul out yearly.

Interestingly, the latest PDF files from international for both Micron 66 and Trilux 33 no longer mention sanding the old antifouling as part of the preparation (only washing and if needed stripping with Interstrip). Although the above warning about not dry sanding antifouling is still included.

My experience is just with hard/slow polishing antifouling. Wet sanding a 47 footer after thorough pressure washing takes about 20 man hours and is HARD work.

Once masking is done, painting is relatively easy. One coat takes about four hours for me to do on my own. As time is generally not critical I have only ever applied one coat a day (total of 3). It needs to be applied while the surface is dry (wait for morning dew to dry) and fresh paint should also not be exposed to moisture. These limitations often make it difficult to apply two coats under ideal conditions.

Only one case to report here, but we wet sanded almost all the old antifouling off last haulout (15 months ago) and our bottom shows only minor scant patches of fouling - the best result in six years of using the same antifouling paint.

I'm getting good at this, I'm but I'm not out for hire .