I've been away from this forum for a couple of years, so I apologize if this has been discussed recently.

My 1982 Nacra 5.0 hulls are having some problems. I keep the boat in a freshwater lake for 5 months of Minnesota summer. I get a lot of algae growth that slows me down and looks ugly. I've also noticed a fair amount of pitting below the water line, which I think contributes to the algae growth. Waxing (after a good cleaning) doesn't seem to help...

I've been reading up on both gel coat repair and antifouling paint. Any recommendations?

I'm looking for solutions that I can implement at home (sorry, I don't have access to a body shop or lots of high-tech equipment). But I'm also not looking at having hulls that are mirror smooth. I'd be happy if the algae fur is shorter than my boyfriend's hair!

Karena,

Most folks here would say "don't leave your boat in the water". However, since that is what you are doing and are comfortable with it, it only remains to get rid of the algae.

You aren't racing, so your best solution is simply to clean the hulls and inspect them for any serious structural issues. If they pass that inspection, choose a good antifouling paint and brush or roll it on following the instructions.

There are probably boat owners on your lake that know what works best there.

And...you can always clip your boyfriends hair. There are also more boys out there if that doesn't work. One of them might have a hot racing cat and you won't even need the bottom job.

Good luck.

great advice Jack!

there are several products on the market that claim to be able to restore old gelcoat. some people swear by them. You can also wet sand the gelcoat (if not shot) to remove crud and restore its shine.

also there are many acid products that are great to clean the surface. many people in my area use sno-bowl (toilet cleaner). it is a good idea to wax the boat after using an acid wash to seal the newly clean boat. this will help to keep it clean.

I just went through a gelcoat restoration job on my N20.

First, clean it with FSR "goop". Its blue. It comes in a jar at West Marine.
http://www.westmarine.com/webapp/wc...1151&partNumber=108753&langId=-1

Then after a thorough washing.... comes the rubbing compound. It goes by quicker with a random orbit buffer.
http://www.westmarine.com/webapp/wc...&subdeptNum=10384&classNum=10385


Then hit it with the finesse-it glaze with the buffer.
http://www.westmarine.com/webapp/wc...&subdeptNum=10384&classNum=10385

Then finally hit it up with a wax of your choosing. I prefer the McLube Hullkote wax.

(Note to Rick, I tried looking for these products in the marine store but it seems that all thats available there is the cleaning wax)

"Hullkote wax" How secure is your footing when righting?

i personally don't wax the top 8" or so of the outer hull, and don't wax the standing area (where i stand to right) inside the hulls.

Pete:

Never had a problem with footing - but I also have straps sewn on the bottom of my trampoline to help me get up on the hull during a capsize.

I also have lots of real estate both on the inside of the hull and on the bottom of my foot

None of that will solve her problem. She needs to prevent algae because she leaves the boat in the water.

She also said she doesn't need a smooth bottom.

Maybe we should rename Tad "Sasquatch" he has big feet too.

Karena,

In all the posts above I haven't seen anyone mention "Gelcoat Blistering" .... these are caused by moisture being trapped between the gelcoat and the underlaying fiberglass. This was a big problem on manufactured fiberglass boats, big and small, if they were left in the water to absorb it over time with boats produced in the late 70's through the 80's. How do I know .... I have a set of TheMightyHobie18 hulls currently in my backyard that will need to have the gelcoat sanded off to remove these "blisters". These hulls were bottom painted which I removed ... discovering the extensive gelcoat
blistering.

Now I think that the solution was that the hull was sanded ... then a coat of epoxy (or coats) were applied ... then bottom paint was used as a outer coating. We had a family friend who had to go through this process w/ his 36ft sailboat at the time.

So I would suggest that some questions/investigation is in order before you use a roller/paintbrush .....

Harry

Thanks to all who have replied. I'm in total agreement with Jack that preventing the growth of algae is essential. Harry's comment has me wondering how to check for blistering. I'm wondering if the pits are blisters that have popped. If so, is further sanding needed? Better to do what's needed instead of making the problem worse, but I just don't know how to tell.....

Karena,

Gellcoat Blistering looks like a really bad case of mosquito bites ..... basically small welts, about the size of a dime or nickle ... a large blister is quarter sized. I can tell exactly how low in the water this TheMightyHobie18 was floating as the hulls have a distinct line which all the "blisters" are below .... and smooth hull above.

I remember reading somewhere years ago when I was in printed circut board manufacturing/assembly that "fiberglass" can assorb up to 1/3 it's wieght in moisture/water .... this is why those of us who race sailboats usually store them in "dry storage" ... even the larger sailboats. The lighter the sailboat ... the less force (wind) it takes to move it ... the faster the sailboat is ...

So ask around for some advise from some of the professional marine people who maintain 25ft or larger boats that spend most of the year in the water. I believe that they have developed "barrier coats" that prevent the absorbtion of moisture .... some of the newer bottom paints may already have been formulated to prevent gellcoat blisters. I just do not know as my boats is "dry" stored on the Yacht Club's lawn or on it's trailer in my backyard.

Of course if you could find away to store your beach cat on "dry" land it would eliminate all of this problem. Now when my boat is sitting on "dry land" (and not on it's trailer) I have made wooden blocks of 4"X 6" Pressure treated wood w/ a 2"X 10" piece of pressure treated wood as a base about 12-14" long (we have termits/carpender ants in Chesapeake/Maryland that love kiln dryed lumber since we usually do not have deeply frozen ground in the winter) ... I use nylon carpet and styrene that do not retain moisture/water to pad the 4X6 to protect the hull. Just having your hulls resting for long periods on wet/damp ground can cause "gelcoat blisters" too.

Harry

PS: When I retire ... I want to grow a long ... long ... ponytail.

Karena - google 'osmosis' in relation to fibreglass. There are instructional videos and links to corrective products out there. Main thing is to get ALL the affected gelcoat and surface resin off and allow the hulls to air-dry (anything up to 6 months) before restoring the bottom finish. Trapping moisture inside the layup with a barrier coat is a total no-no!

Harry, good point.

Because polyester gelcoat will absorb water over time people who leave their boats in the water usually apply an antifouling paint which actually sloughs off over time revealing more of the toxic copper or organic compounds to fight off growth. A lot of the racing mono's will apply an epoxy barrier coat to help reduce water absorption under the ablative paint.

Blisters have to be broken and allowed to dry out completely before they can be repaired, faired, and recoated.

I have actually seen some cats with small blisters forming from resting on the carpeted sections of the hull cradles on trailers that had remained damp.

While it may not happen in this case if your thinking of re-gelcoating your boat there is vinylester gelcoat available. Does not absorb water. It's a much better product. I'm to the point where I don't use polyester for anything.

Consider googling a Barrier Coat such as VC 17 Tar.
(by the way 5 coats per manufacturers recommendation, 1 coat does not work)
http://catalina-capri-25s.org/forum/topic.asp?ARCHIVE=true&TOPIC_ID=8955
http://forums.sbo.sailboatowners.com/printthread.php?t=13082

Harry et al,

Thanks to all for the advice - there are so many possibilities here. I've re-examined the hulls are there are no blisters. Osmosis may be a factor, in that the last two years the hulls have taken on a small amount (~1 gallon during 5 months) of water without a discernable leak.

I'm hoping that a coat of anti-fouling paint (epaint?) after a winter in a dry garage (humidity is low up here, but the snow is high) will both seal things better against osmosis and prevent the algae growth.

I really wish I could store this lovely boat out of the water, but proximity to a good lake; the time, effort, and logistics of taking it in and out frequently would curtail my sailing time so much that I'd probably only take it out once or twice a year, and it would eventually die a sad death in a back yard. I'd rather do some extra work every year or two, sail frequently even if not at optimal speed; and thoroughly enjoy every day I'm out there.

If you have power in your garage, store the boat with hatch covers off and dangle a 60w or 40w bulb (on continuously) through each of the two centre hatches. Low tech way of 'force' drying the hulls over a long period at low cost with low risk.

Jalani,

I've done the same thing using lightbulbs to dry my hulls out over the winter .... just don't let the bulb get close or touch the fiberglass as you can "burn" the resin (fiberglass cloth won't burn at those low tempatures) .... don't ask how I know but I have personal experience w/ that mistake .... (afterwards) ... I used old hull port covers/hatch covers and mounted a light, centered, in them using lamp sockets/lamp cord/hardware purchased at my local hardware store. So for the winter I "tent" the boat w/ a "blue poly tarp" and just set the hull covers in place (loosely w/o gaskets) .... I can see the hulls glowing from the internal light in my backyard during the winter.

The garage is usually filled w/ (other) active projects so the hulls can not be stored there .... luckly we usually don't get alot of snow here .... except for last year!!!!!

Harry