CLEANING HULL BOTTOM

[RHC]

Due to bad planning, my boat will be in a slip for a week (maybe 2) w/ no bottom paint while trailer is under repair.

I've done this once (obviously did not learn my lesson), so I expect the bottom to be green w/ algae when I get it out of the water.
Besides brute force w/ pressure washer, is there a better way to clean? Does it help to let it dry out first, or does that make things worst?

thanks,
RHC

[Matt19020]

Two weeks is not too bad ...I think you could pick up a "hull cleaning solution" and a pressure washer it should come up like new. I left mine in for 5 weeks before I used bottom paint and it looked pretty good after that procedure.

[NiceAft]

Do a search of Slimy Grimy. I've always had good results. Others...........not so, but me, yes!

Ray

[bscott]

Do not let it dry out

Bob

[Currie]

Some info here...

http://www.macgregorsailors.com/forum/v ... =8&t=13355

~Bob

[waternwaves]

If I need the hull cleaner after pressure wash....... goggles, gloves, overalls.......

I use the hull cleaner that is the 3 acid combo.....hydrochloric, phosporic, oxalic.......acids..., used very very sparingly. Especially useful at removing the brown water stain, apply, wait 60-120 seconds........softscrub off with lots of water.

But be very very careful and wax when done.

[puggsy]

Sorry, but I have to disagree somewhat with BScot..You can allow a fibreglass hull to get as dry as it wants...thats the hull...NOT so with a timber hull...
What he probably means is to not let the GROWTH dry out before hitting with the pressure washer. A while back I posted pics of SEAHORSE's hull after about 8 months...pretty bad...The moderate KARCHER [ 1500 psi] got it all off the morning AFTER THE DAY I put her on the trailer...but I would not have left it a week...
If you are continuing with applying antifouling, what does not come off with the pressure clean...just leave it on and paint right over it with this years coat.

[Duane Dunn, Allegro]

Perhaps things are different down south, but I've had mine in the salt water without bottom paint up here for 2 - 3 weeks many times and there is never much more than a bit of fuzz at the water line. Perhaps this is because I have been using the boat and the water flow has limited the growth.

The trick is as mentioned, don't let whatever growth there is on the hull dry out, it becomes twice as hard to get off. If possible scrub what you can at the launch right after you pull the boat out. When it is fresh and alive it will come off with a light scrubbing from a brush on a pole, later in the driveway when dried even the pressure washer may not take it all off.

[Chinook]

Since I normally store my boat on the trailer, I've opted not to bottom paint. I've grown a number of interesting collections of marine life on her bottom while on extended cruises, both in cold northern and warm southern waters. In each case I scrubbed the bottom at the ramp right after pulling her out, while things were still wet. It's always a hard job, but I figure bottom painting involves work too, plus expense. I have used anti fouling wax instead, and feel that it has helped, but can't quantify the benefit. Maybe I'll do a little test sometime, and only wax half the hull. For removing the harder, calcified growths, I've found a 4 inch metal putty knife to be effective. I've rounded off the sharp corners with a file so they're not prone to scratching. Used with care, it does a good job and doesn't scratch up the hull. On the Sea of Cortez cruise I cleaned the bottom while on the water after about 4 weeks, and it worked out great. I'd tried beaching before, but the boat moves around too much with wave action, and there are always places you can't reach. What I did down near La Paz was find a nice shallow bay with a clean white sand bottom. I anchored in about 2 1/2 feet of water, about an hour before low tide. I set both bow and stern anchors (easy since all I had to do was walk around and place the anchors - I love the Mac's shallow draft qualities), and pulled both rodes tight, so the boat remained nice and stationery. Then I hopped in the water with my putty knife and a white scrubbing pad and went to work. I could easily clean the sides around the water line, and could reach all but a 4 foot wide strip down the bottom of the hull. With my face mask and weight belt on, I held my breath and easily finished the hard to reach places. I experimented with a breathing tube, but found it easier to just hold my breath and clean with repeated dunks. This is definitely the best way I've found to clean the bottom, but obviously it requires relatively warm water to be practical.

[RHC]

Well, the estimated 1 week repair on the trailer turned into 3. Since slip price for 3wks is same as per month, just kept boat in the water for the month. Pulled it out last Sunday, algae growth looked gross. Most of it came off w/ pressure wash, but still quite a few bits left, by the time it got dark.
No time after work, so it'll be nxt week end when I finish off cleaning. As I read this thread, looks like the last 10% of the work will be a bear.

I like the comment: "what does not come off with the pressure clean...just leave it on and paint right over it with this years coat". I guess it's all cosmetic, right? Keeping bits stuck does not degrade Fiber glass???

RHC

[Currie]

The hydrochloric didn't do the trick? I powerwashed and even sanded almost to tears, until the growth just literally fell off using TheWorks. It took me a little over an hour and about $11 to get it spotless.

~Bob

[Boblee]

Last year I spent nearly three weeks getting all the growth off after only 6 weeks in tropical salt water so trialled using lanolin grease below the waterline at Gippy Lakes last year and was so pleased I rolled a full coat on before launching this year on the Roper River.
Spent about 9 weeks on the water while away but probably only 5 weeks on salt water, haven't touched it yet but I expect it will just blow off with the pressure washer as there is absolutely no marine growth just muddy slime from the last bit of fresh in the Norman River.
Some of the bottom is clean where we beached accidently on a shallow bar, actually run aground on sand quite a few times.
The Dinghy looks to be a far worse job than the Mac.

[bubba]

We have bottom paint that was painted on before we bought our M and in all our sailing we have not collected any groth on the bottom but our dagger board was only painted about 18 inches up from the bottom and needs to be cleaned regularly to keep grouth off. I just pulled the dagger board off last week to clean it, we had barnical footprints all over it above the bottom paint from the previous owner leaving it down at dock for the 6 months they owned the boat. I plugged the holes in the bottom of the daggerboard and added 50 lb of lead and repaired the back edge where it had chipped with 1/2 inch of CPVC epoxied to the board. Since many inland lakes now check for Zibra mussles at there launches I did't need to be turned down for having mussles growing inside the dagger board like where I found there shells.

[johnnyonspot]

In the other linked thread someone said Starbrite is a joke. This is directly contrary to my experience. I had my boat in a slip all season long up here in Minnesota and Starbrite cleaned it right up. Took slightly less than one bottle to clean a Mac 25 hull. My bottom may have gotten less gunk on it being up here in Minnesota where the water is fresh and relatively cold, but it cleaned up real nice and the Starbrite was not nearly as irritating as the muratic acid I once used.

[NiceAft]

I thought I would post this picture I took of my hull after I sprayed with Slimy Grimy, and let it run down the side.


Ray