Last winter I hauled my 85 Hunter 31 out for the winter...gave her a new bottom coating and waxing....planned to do the same this year, but poor weather and very low water has kept me from getting to Crab Alley (where she would spend the winter)..My question, does leaving her in the water over the winter increase the risk of haul problems, blisters, etc. I've had several folks tell me that it doesn't make a difference......
- Status
Probably Not
Those of us in SoCal only haul for a couple of days every couple of years. We get blisters, but not many more than New England based upon the comments on this board. So, I think the short answer is don't let blistering propensity be a factor in your decision. Particularly a one-season decision. Rick D.
Those of us in SoCal only haul for a couple of days every couple of years. We get blisters, but not many more than New England based upon the comments on this board. So, I think the short answer is don't let blistering propensity be a factor in your decision. Particularly a one-season decision. Rick D.
Hauled every two years at Annapolis
Gil; I owned a 32 different brand and kept it in Annapolis hauling every two years. Unless it gets terribbly cold and water is freezing, then I would leave her in but have it hauled in the spring to clean the bottom which I did. Crazy Dave Condon
Gil; I owned a 32 different brand and kept it in Annapolis hauling every two years. Unless it gets terribbly cold and water is freezing, then I would leave her in but have it hauled in the spring to clean the bottom which I did. Crazy Dave Condon
Rick, Yes you do!
Warm fresh water is the worst for blisters! You get more. A 1990 New England may never get a blister!
Warm fresh water is the worst for blisters! You get more. A 1990 New England may never get a blister!
3 Years!
I'm getting 3 years on my haulouts in S. Texas. Last one I had a few blister, nothing unusual. Royce
I'm getting 3 years on my haulouts in S. Texas. Last one I had a few blister, nothing unusual. Royce
Why greater chance in fresh water??
I'd be interested in finding out why someone indicated fresh water boats supposedly have a greater likelihood of getting blisters than those kept in salt water. I can understand temperature may be a factor but salinity? Don Illusion
I'd be interested in finding out why someone indicated fresh water boats supposedly have a greater likelihood of getting blisters than those kept in salt water. I can understand temperature may be a factor but salinity? Don Illusion
Salt vs fresh water for blisters
Fiberglass blisters occur because water passes through the gelcoat. Water soluble chemicals inside the laminate exert an osmotic pull on water outside, and some water molecules find a way through the gelcoat. As more water is attracted into the enclosed space, internal pressure builds. The water molecules aren't squirted back out the way they came in because they have combined with the attracting chemicals into a solution with a larger molecular structure. Instead, the pressure pushes the covering gelcoat into a dome-a blister Permeability of fresh water is much greater than that of salt water.
Fiberglass blisters occur because water passes through the gelcoat. Water soluble chemicals inside the laminate exert an osmotic pull on water outside, and some water molecules find a way through the gelcoat. As more water is attracted into the enclosed space, internal pressure builds. The water molecules aren't squirted back out the way they came in because they have combined with the attracting chemicals into a solution with a larger molecular structure. Instead, the pressure pushes the covering gelcoat into a dome-a blister Permeability of fresh water is much greater than that of salt water.
Still don't get it
Jim Sorry to get anal about this but I still don't get it. I understand the thoery which describes why blisters occur - just not your last statement which doesn't lead from the process you describe about the concept why a fiberglass/gelcoat hull is more permeable to fresh water. Based on the premise that there is sufficient water to initiate the process regardless of whether salt is also present, does the salinity of the water have any affect which changes anything and if so, why? Don Illusion
Jim Sorry to get anal about this but I still don't get it. I understand the thoery which describes why blisters occur - just not your last statement which doesn't lead from the process you describe about the concept why a fiberglass/gelcoat hull is more permeable to fresh water. Based on the premise that there is sufficient water to initiate the process regardless of whether salt is also present, does the salinity of the water have any affect which changes anything and if so, why? Don Illusion
Chemistry 101
Osmotic blisters on boats are due to the diffusion of water molecules through the semi-permeable membrane of the hull’s gelcoat. The osmotic pressure of water on the gelcoat dependents on the molar concentration of water in the liquid and the absolute temperature of the liquid. Fresh water has a higher molar concentration of pure water than seawater; therefore fresh water has a higher osmotic pressure than seawater on the hull’s gelcoat. An increase in temperature will also exert an increase in the osmotic pressure causing more molecules of water to pass through the hull's gelcoat, that’s the reason boats in freshwater lakes in the South have more blisters than boats in cold water lakes in the North. Fair Winds. Clyde
Osmotic blisters on boats are due to the diffusion of water molecules through the semi-permeable membrane of the hull’s gelcoat. The osmotic pressure of water on the gelcoat dependents on the molar concentration of water in the liquid and the absolute temperature of the liquid. Fresh water has a higher molar concentration of pure water than seawater; therefore fresh water has a higher osmotic pressure than seawater on the hull’s gelcoat. An increase in temperature will also exert an increase in the osmotic pressure causing more molecules of water to pass through the hull's gelcoat, that’s the reason boats in freshwater lakes in the South have more blisters than boats in cold water lakes in the North. Fair Winds. Clyde
that s right jim
Been painting boats for years and the fellow is right on the money. Inland fresh water in warmer climates do have a tendacy to produce more blistering. Experience teaches me. Crazy Dave
Been painting boats for years and the fellow is right on the money. Inland fresh water in warmer climates do have a tendacy to produce more blistering. Experience teaches me. Crazy Dave
Always learn something here
Thanx for the explanation - this is a great place to learn... I am a chemical engineer who claims to know little abour chemistry other than its practical utility. Consequently, I'll still believe that the cause of blisters has a lot more to do with hull lamination characterisitics, workmanship which went into the layup and water temp than it does from the density difference. Don
Thanx for the explanation - this is a great place to learn... I am a chemical engineer who claims to know little abour chemistry other than its practical utility. Consequently, I'll still believe that the cause of blisters has a lot more to do with hull lamination characterisitics, workmanship which went into the layup and water temp than it does from the density difference. Don
best thing - being in the water
bottom paint was made to be in the water. having it exposed to above water elements dries it out leading to the fine cracks, flaking, etc., you see which lead to the paint not lasting so long. GOOD quality paint put on a well prepared surface should last a long time. haul out in early spring light sanding and a coat of fresh paint - same sort - is all that is required. fresh/salt water with good quality bottom paints does not make much difference. pettit epoxy is what we use in what i call half salty water. where we do not get much tide - 2 feet at the most. get a leaflet of good quality paint such as pettit which will explain the different paints for different conditions or visit their website and send an email to confirm re keeping boat in water over winter. surface prep is the most important. if applied initially with work, the hull should not have to stripped for several 6-7 years if then. commodore of prestigeous yacht club locally - annual sub starting at 1,500 dollars/year for non-boat owning membership! - takes his sailboat out of water once in 4 years to sand and re-apply bottom coat. has someone with snorkel to brush underwater every yesr. boat looks and sails really great and wins plenty of races! has crossed my mind that minnesota is pretty cold during the winter. you want to be careful that the water does not freeze to any extent around your boat. the actual freezing does not do the harm but when the ice begins to melt around the hull and the boat moves in the ice due to wind, waves, etc. then damage can easily occur to your fibreglass due to the sharp edges of the ice. if this is likely to a problem, use a bubble jet or something else to prevent the water from freezing immediately around your boat. this was not such a problem with wooden boats back in the 'good 'ol days'! hope of some help.
bottom paint was made to be in the water. having it exposed to above water elements dries it out leading to the fine cracks, flaking, etc., you see which lead to the paint not lasting so long. GOOD quality paint put on a well prepared surface should last a long time. haul out in early spring light sanding and a coat of fresh paint - same sort - is all that is required. fresh/salt water with good quality bottom paints does not make much difference. pettit epoxy is what we use in what i call half salty water. where we do not get much tide - 2 feet at the most. get a leaflet of good quality paint such as pettit which will explain the different paints for different conditions or visit their website and send an email to confirm re keeping boat in water over winter. surface prep is the most important. if applied initially with work, the hull should not have to stripped for several 6-7 years if then. commodore of prestigeous yacht club locally - annual sub starting at 1,500 dollars/year for non-boat owning membership! - takes his sailboat out of water once in 4 years to sand and re-apply bottom coat. has someone with snorkel to brush underwater every yesr. boat looks and sails really great and wins plenty of races! has crossed my mind that minnesota is pretty cold during the winter. you want to be careful that the water does not freeze to any extent around your boat. the actual freezing does not do the harm but when the ice begins to melt around the hull and the boat moves in the ice due to wind, waves, etc. then damage can easily occur to your fibreglass due to the sharp edges of the ice. if this is likely to a problem, use a bubble jet or something else to prevent the water from freezing immediately around your boat. this was not such a problem with wooden boats back in the 'good 'ol days'! hope of some help.
- Status