I have read in this forum about fibreglas having osmosis absorption problems. I have the use of a slip for the summer. I didn't plan on
keeping the boat in the water continuously...but the slip would make it
more convenient (rigging,etc.)
So my question is how long can I leave my 26 in the water before I would have to put her back on the trailer to 'dry out'.
How many owners don't have bottom paint...and if so how long do you
keep your boat in the water before you haul it back out.
How long can you keep a Mac in fresh water before a bottom paint would
become imperative?
Mine stays in a slip from May til Sept, and last year was the first year I bottom painted. Before that I used lots of wax to try and keep the crap off, but still had a big job in the fall to get it clean. Last year, 20mmin with a pressure washer and done. This year, just a few touch ups , and back in the lake.
Some freshwater lakes have zebra mussels that are almost as aggressive as barnacles. Bottom paint is a good thing if in one of these lakes. Probably includes most of the great lakes by now. For sure lake Erie and probably Ontario. Not sure about the other ones but I would guess they would have spread around by now with all the ship traffic. .
This also is a reminder that we should be aware, as water ballasted boaters, that we should make sure that we do not contribute to the spread of these generally unwelcome beasties. In other words, heavily bleach or otherwise treat the ballast tank if moving the boat from a zebra mussel lake to another fresh waterway.
If no zebras, you can probably get away with less than bottom painting, if you want to put in extra work waxing and cleaning the bottom.
Personally, I would just paint the bottom and be done with it. But I know it is tough to mess up a nice shiny new bottom with paint.
I put 10 coats of PolyGlow below the waterline, and 6 on the upper hull.
(PolyGlow states at least 6 coats).
I am going to keep the boat on an inland lake...no zebra mussels etc.,
could have some algae buildup...but I figured if I had to I would pull her
out and pressure wash before the end of the summer.
I am not so worried about plant growth as I am about osmosis problems.
Well, keep in mind there are two issues, each requiring a different solution...
Blisters and growth... These are two different issues.
You need a Barrier Coat (essentially expoy paint) to prevent blisters. Trailering isn't an issue with this... This goes on smooth, actually smoother that the stock polyester resin... This won't present a high drag surface.
You need Bottom Paint, which is the thick rough stuff, to prevetn growth. This will present a high drag surface. This also is what looks like crap if not kept up. We've all seen 'those' boats...
As I understand it, the common approach it to apply a barrier coat and then apply bottom paint on top of that...
I understand that there are waxes that 'temporarily' address both problems.
We just got our boat and have nothing on the bottom. So, we'll store it on the trailer for the first year. Then, over the winter, I plan to have someone fix the little dings/gouges my learning curve is inflicting, and apply a barrier coat. Next year, we'll try to store it on the water and see it we need the bottom paint...
My 2002X had a brand new clear epoxy bottom paint on it when I purchased it,and that should of alerted me to the possibility that there had been a problem. The previous owner got the factory to pay for the job when the boat blistered after sitting in the water a few weeks unprotected.
I applied 2 coats of Aurora bottom wax to the newly epoxied hull and then put it into Lake of the Woods at a slip for the summer.When I hauled it out in the fall,it was covered with tiny blisters. A phone call to the previous owner and to the shop that did the epoxy coat revealed that the wrong product had been applied.
I sanded the bottom and applied Interlux Interprotect 3000 (4 coats) followed by 2 coats of antifouling.
My 1988 26D also blistered and was repaired with the barrier coat and no antifouling.
I think that some boats come from the factory more susceptible than others and I think that Northern fresh water lakes cause more problems,but I can't explain why.
Doing research and talking to a lot of folks before getting my boat last year, the common wisdom seemed to be that I didn't need a barrier coat because (a) blisters should not be a problem with "modern" fiberglas resin/gelcoat unless the boat was going to be in the water year-round for more than a year, and (b) I knew the boat was going to spend 5-6 months of the year on the trailer.
So, I did not get a barrier coat. Left the boat in her slip in salt water for six months straight last year, with one ten-day trip to a fresh water lake, and no blisters at all.
I'm using ablative bottom paint - it is rough and chalky, so does impact boat speed, but it is not affected by exposure to air - so you do not waste it by leaving the boat on the trailer. It works wonders against marine growth!!
Does anyone have a photo of the kind of "blisters" that are being mentioned in this thread? It would be great if a photo could be posted, as it would be very interesting to see an example of just what it is we should be looking out for.
Blisters are caused by osmotic pressure across a semipermeable membrane (gelcoat or the outer layer of resin). This is the same force demonstrated back in beginning chemistry classes, where a salt water solution is put on one side of a membrane and fresh water on the other. The fesh water "wants" to to join up with the salt. (the salt cannot cross the barrier, but the water is small enough to go through the pores). So the fresh water crosses the barrier and joins the salty side. THis is shown in the experiment as a rise in water level on the salty side.
Same thing happens on the hull. Especially if the fiberglass has a messed up composition, or has areas that were not wetted out properly, water is pulled across the semipermiable barrier (the gelcoat or outer layer of resin) and builds pressure once it enters the defective fiberglass area, pushing out the barrier to form the blisters.
Salt water is much less prone to causing blisters, because the water is already mixed with salt and there is little or no osmotic pressure between that and the defective fiberglass. WHile the fiberglass is probably not salty, it has other stuff in it that acts like salt for the purpose of osmotic pressure generation. This is one of the properties referred to as colligative properties, where the effects are independant of the actual component. (osmotic pressure, boiling point elevation, etc).
The temperature of the water would simply effect the rate of blister formation.
The epoxy bottom coat is applied to close up the pores in the semi-permeable membrane to make it a true barrier and keep the water from crossing into the defective fiberglass areas.
Other examples of semipermeable membranes are found in batteries, to force the electron exchange to occur across the terminals, instead of by simple movement through the electrolyte.
I am going to cross my fingers and hope that not too much damage might
occur this summer by not having painted the bottom.
If I find this fall that blistering has occurred...would sanding and applying an epoxy coat stop the blistering? I probably would have a professional do the painting.
Does painting the bottom stop any further damage...or will I have permanently damaged the hull?
in the water before I would have to put her back on the trailer to 'dry out'.
