A Bazillion Blisters - Will They Get Worse?

[El Pinguino]

The main problem that you will have with those blisters ( in the short term ) is that every time you haul all the 'yard experts' will be telling you and everyone within earshot that she is unseaworthy, about to delaminate and fall to bits, and that, if you go to sea in her she - and you - will simply disappear without a trace.

That said it will be easier, faster and cheaper to fix her now than in five years time.

[minaret]

Originally Posted by ScottMeilicke

From what I read in the article I posted earlier, if you don't get rid of the glycol (hydroscopic), you will still have water, which will then continue to suck water through your hull via osmosis, causing more blisters. Since glycol is molecularly much larger than water, it has a much harder time migrating out through the plastic. Therefore you have to cut/grind it out, and washing with warm water helps. Perhaps in your case the epoxy has slowed the osmosis, but it will come back at some point, perhaps through the inside!

Oh, well researched! You are certainly more well informed than the average joe on the topic. There are two basic approaches-remove the affected material, or dry it out/remove the contaminants. Both can be done efficiently, with the right approach. Whether one approach or both are used depends on the severity of the case.

[minaret]

Originally Posted by Steady Hand

The previously linked article was a very interesting read. Lots of information and well illustrated too.

Here are a few excerpts I found interesting and thought might spur some comments here in this thread:

SOURCE: http://www.passionforpaint.co.uk/pdf/osmosis3.pdf

__________________________
EXCERPTS:

PAGE 6

"Ironically, the most widely accepted answer to this problem is to ‘dry’ the hull with infra red heaters and dehumidifiers, after which the hull is quickly painted with an epoxy coating scheme ‘before the water gets back in again!'

Unfortunately, this rather simplistic approach to correcting high moisture meter readings usually causes more problems than it solves; for whilst a correctly applied epoxy may slow down the rate of moisture ingress, its densely cross-linked polymers will also prevent the escape of hygroscopic solutes - which means that blistering is even more likely to occur than if the gelcoat was left unprotected!

So: whilst ‘drying’ will undoubtedly help to reduce moisture meter readings, it will do nothing to remove the solutes which are the real cause of our problems, and will not provide a permanent cure. Osmotic breakdown is not a reversible process, so simply removing moisture will never cure it!

I am not suggesting that abnormally high moisture readings should be ignored; but there is usually no need for alarm.

In practice, many yachts are sailed for with ‘high’ moisture readings for ten years or more without their owners being aware of any problems; so the perhaps best advice at this stage would be to leave well alone, whilst keeping an eye on the problem, and delaying any further damage by wintering ashore if at all possible.
_______________

Blistering:
Osmotic blistering is usually a comparatively superficial problem, which only affects the protective gelcoat layer on the outside of the hull. The gelcoat itself is rather like a thick coat of paint, typically about 500 μm (1⁄2 mm) or 20 thou thick; although there can be significant variations in thickness from one part of a hull to another, and between different hulls.
Crucially though, the gelcoat layer itself has very little mechanical strength, and is used only to provide a glossy, hardwearing exterior finish and to help protect the structural laminate beneath it from the effects of water ingress and ultraviolet degradation. Polyester gelcoats are also notoriously brittle, and will readily crack or shatter if stressed, resulting in the characteristic ‘spiders web’ effect.

De-Lamination:
Osmosis does not cause De-lamination, but if the laminate is poorly invested with resin, the internal hydraulic pressure generated by the osmotic process may separate (or de-laminate) any poorly adherent layers (or plies) from one another, severely weakening the hull.

This effect will usually be identified by visible undulation or large ‘swellings’ in the hull surface, although classic ‘Osmotic’ blisters need not be present in the gelcoat.

The hull may also appear slightly ‘soft’ if pressed firmly with a thumb nail or a tool, and may sound ‘dead’ or ‘dull’ if tapped gently with a plastic faced hammer.
In this context, the shape and size of any blister formations will often provide a useful indication of the laminate condition beneath:
• Small, or well formed blisters usually indicate that the gelcoat is adhering well to the laminate, and that the laminate itself has good interlaminar adhesion.
• Shallow and irregularly shaped blisters are usually formed where adhesion between the gelcoat and structural laminate is poor. In some instances, two or more blisters will merge together to form larger blisters, again indicating poor adhesion between the gelcoat and laminate.
• Very large and shallow blisters, or unevenness (lumpiness) in the hull surface usually indicates some form of de-lamination. 
Whilst most yachts can be sailed perfectly safely with their gelcoats in a blistered condition, symptoms of de-lamination must be investigated by a Surveyor as a priority. "

__________________
END OF CLIP

I would agree with the majority of this quite strongly, yet this person appears to have never heard of hydrolysis.




NHML Hydrolysis of Fiberglass - NHML




Hydrolysis of Fiberglass

Hardly a week goes by without our being asked to do a failure analysis of something made of fiberglass. The failure may be an industrial tank, piping, a yacht hull, a swimming pool, or a water tank in an RV. This issue of “Nuts and Bolts” addresses the failure called “hydrolysis”, as well as a very different kind of failure due to leaching of a constituent in the fiberglass’ resin. We hope neither of these happens to you, especially since the insurance industry usually classifies these as “wear and tear” failures so they are not often covered.

Overview of the Chemistry

All of the different molecules that can be used to make up the various polyester-based fiberglass resins are subject to deterioration by hydrolysis. For hydrolysis to occur, water as liquid or vapor must be present. The reaction is markedly accelerated by elevated temperatures. In the hydrolysis reaction, water molecules break up the resin molecules, leaving an organic acid of varying acidity depending on the particular resin and a mixture of molecules of water, alcohols, and glycols. After a period of time, only the heavier alcohols and the glycol will remain.

Technical Background

An ester molecule has the following structure: The hexagon is a ring-type group such as a benzene. In polyester, R is a carbon and hydrogen chain-type group. In vinyl ester, R is a vinyl chain. When these esters undergo hydrolysis, a water molecule attacks the bond between the central carbon atom and the adjacent single-bonded oxygen atom. The water molecule dissociates into a hydrogen atom and an OH pair. The OH pair takes the place of the original singlebonded oxygen while the hydrogen joins the O-R to become H-O-R. The C = O pair is referred to as a carbonyl. The OH group’s electrons are somewhat mobile within the molecule, wandering between the OH and the double-bonded oxygen. If, in a particular molecule, the electrons divide their time between the OH pair and the double-bonded oxygen, then the molecule is a weak organic acid. Should the bonding electrons spend much of their time away from the OH pair, the resulting electron deficiency makes the molecule into a stronger organic acid. The degree of acidity is increased by the presence of nearby “electron withdrawing” atoms or groups. For example, chlorine is a strongly electronegative atom that increases the acidity through “electron withdrawing” from the carbonyl. In the particular case of a hydrolyzed polyester, the acid product is carboxylic acid. The molecule that is cut loose during hydrolysis could be a water molecule, an alcohol, or a glycol. After hydrolysis has occurred, the water and lighter alcohols will be lost by evaporation. Heavier alcohols and glycols do not volatilize but will accumulate.

1

NHML Acquires DSC

A Differential Scanning Calorimeter (DSC) is an instrument which accurately measures the heat absorbed or given off from a sample as a function of temperature. Such thermal parameters as the Glass Transition Temperature (TG) (which is the temperature at which a glassy material begins to flow), the melting temperature, and the enthalpy of melting can all be measured by DSC. Our main interest will be the melting temperatures and glass transitions of polymer samples, however, the DSC can measure thermal properties for crystalline organic compounds and liquids as well. DSC data is most often used in conjunction with TGA data (which gives weight loss as a function of temperature) and FTIR data, which provides the identity of a polymer sample. Such thermal parameters as the glass transition, melting point, and decomposition temperature are useful to engineers who must select polymers to withstand a given thermal environment.

Hydrolysis Failures

Delamination, blistering, and bleeding are the common failures. After having set, the original polyester molecules are immobile. After hydrolysis, the new molecules have some mobility and also occupy a greater volume than the polyester molecules from which they came. The result is internal pressure. The pressure, along with the natural mobility of the molecules, causes them to fill any voids in the fiberglass, including the pinhole porosity that is always present. If they can’t escape to the surface fast enough, and if there are any deficiencies in the composite, then blistering and delamination are common results.

The first requirement for hydrolysis is water absorption. A dry sailed boat or an intermittently used tank will probably not fail by hydrolysis. A swimming pool that is always filled, a yacht that is always afloat, or a tank that is usually filled are candidates for eventual failure. Because elevated temperatures accelerate the hydrolysis reaction, both delamination and blistering are more widespread in southern climes. A tank holding warm water is especially at risk. Fiberglass structures that are well sealed by their gel coat or another surface coating may suffer severe blistering since the byproducts of the hydrolysis reaction may not be able to escape as fast as they form. A swimming pool or a hot tub that has a good gel coat on one side only may not blister or delaminate since the byproducts may be able to escape out the back door.

1A yacht or a tank that is well sealed on both sides is more likely to develop the internal pressure that is the precursor to structural failure.

When we encounter widespread delamination it is often in deficient layups that have insufficient strength to withstand the internal pressure. Analyzing these layups, we may find high resin/glass ratios, resin pockets and porosity.

Bleeding is another failure. Even the best fiberglass composites have at least a few pinholes where the reaction products concentrate. Sanding the fiberglass in preparation for refinishing may break into these pinholes. They release a fluid having an acidic smell along with the color of the glycol component, often a green or blue. When we recently analyzed a smelly, blue goo bleeding from the pinholes on a yacht undergoing resurfacing, we found it to be predominantly the carboxylic acid that forms during failure by hydrolysis.

Leaching

When organic liquids are stored in fiberglass tanks or run through fiberglass piping, the possibility is always present that the stored liquid may dissolve some constituent out of the fiberglass. We have analyzed gasoline stored in fiberglass and found some of the lightest molecules in the gasoline diffusing out of the gasoline and into the fiberglass. At the same time, some heavy molecules were dissolving out of the fiberglass and into the gasoline. Only recently has ethanol been added to gasolines, with 10% a common amount. The ethanol in the gas can dissolve some molecules in the fiberglass that always used to stay put. Fortunately, most of these molecules burn right along with the gasoline so we never notice that they are present. Unfortunately, the 10% ethanol in E10 gasoline is picking up some phthalates in older fiberglass. The phthalates are particularly stable molecules that seem to be traveling through an engine’s induction system as extremely fine droplets. When these droplets reach the hot back side of each intake valve they stick and, instead of burning, they decompose into a heavy deposit of black goo. (We can tell you the chemistry of the goo, but you probably wouldn’t be interested!) That goo can cause the valve to hang up, followed by the piston hitting it on the next revolution, resulting in very bad things happening immediately in the engine.

So far we have only seen the problem in some pre-1980 yacht tanks. We are keeping our fingers crossed for the E10, the E85 that is just beginning to be introduced, and who knows what molecules that are going to be appearing in biodiesel.

[minaret]

Hartoft Marine Survey, Ltd., Annapolis





Fiberglass Blisters

Explanation, Diagnosis and Repair

The following is an attempt to demystify and clarify the fiberglass blister problem.

Past survey observations by Hartoft Marine Survey, Ltd. indicate that approximately 70% of the fiberglass vessels in the Chesapeake Bay area when inspected have fiberglass blisters to varying degrees of severity. This figure has recently been decreasing probably due to repairs having already been made. It is believed that approximately 95% or more of all fiberglass vessels in this area have, had, or will have, fiberglass blisters. Further observation shows that bottom laminate constructed with the commonly used orthophalic resins has a life expectancy of around 30 to 35 years before deterioration due to blistering and resin damage has structurally weakened the bottom laminate. This deterioration can often be observed as flexing of the bottom laminate when hand pressure is applied even on boats in the 40' to 50' range.

Some manufacturers have recently changed the resin types used in construction to higher quality resins (to isophalic or even better vinyl ester resins) in all or some of the outer layers of their vessels. Depending on resin type and application some of the comments above and below may not apply. Please consult with the builder for the exact specifications.

What is commonly referred to as a "Fiberglass Boat" is more correctly a "Fiberglass Reinforced Polyester Resin Boat". The hull skin is normally built in a female mold. First gelcoat is sprayed in the mold and then successive layers of different types of fiberglass (cloth, matte, roving, etc.) is layed into the mold one at a time and wetted out with polyester resin forming a hull consisting of many layers (or laminates) of fiberglass bound together with the resin.

Fiberglass blistering is caused by one or more factors such as resin type, contamination of materials, trapped gases, built-in voids, poor wetting out of laminate, incorrect humidity or temperature and dry layup. Osmotic fiberglass blistering is a process which depends on the temperature of, and exposure time to, the water. Given the above mentioned factors, it is not surprising that fiberglass blisters appear on a large number of vessels which are kept afloat for long periods of time in relatively warm water.

Fiberglass blisters form only when water penetrates to the laminate. This water not only damages the laminate by forming blisters causing localized delamination but also combines with uncured water soluble and hydroscopic components in the resin forming an acid solution which is highly corrosive to even the well cured polymers in the resin. As more water reaches the laminate, more corrosive solution is formed and more resin broken down. The effect is that of flushing the resin out from between the fiberglass strands. A laminate so affected is often referred to as having been hydrolyzed.

When a laminate gets hydrolyzed, a loss of strength takes place mostly in the form of increased flexibility. The hydrolysis is very layer specific and does not normally extend to the same degree through all layers. Consequently, the loss of strength can be quite high in the outer layer but the overall loss of strength in the hull itself minimal at least early on in the process.

Fiberglass blistering is a fairly rapid destruction of the outer layer of laminate (occasionally two or more layers) in the form of delamination due to the blister action. Typical blistering starts when the vessel is 5-10 years old (applying a barrier coating may delay the formation of blisters). All blisters will eventually break (unless the entire affected layer delaminates, a very rare occurrence) given the initial impression of a blister free bottom. Occasionally, blisters may then again form, this time further into the bottom laminate creating new and deeper blisters.

Hydrolysis (resin depletion) is a rather slow deterioration of the laminate (30-35 years) usually starting in the outer laminates and given enough time eventually affecting all laminates in the layup. Broken fiberglass blisters allow the water to reach the deeper layers of laminate more quickly, but hydrolysis often prevents blisters from forming in deeper layers due to the porosity caused by the resin depletion (in order for blisters to form, a membrane capable of holding pressure must exist).

Hydrolysis can be recognized by resin "wash out" between the fiberglass strands leaving a laminate that appears to be "dry", lacking resin. The resin remaining will be soft giving low barcol readings (below 40-45) and if the condition is severe, the bottom laminate may be easily deflected by hand pressure and will sound dull when percussion tested.

From the above, it follows that the most effective way to avoid blisters and laminate damage is to not expose the laminate to water. This can be accomplished by keeping the boat out of the water or if you want to use your boat, by applying barriers to slow down water absorption. If the boat is new and has never been in the water, a barrier coating can easily be applied. If the boat is used and maybe even has blisters, things become more complicated. Please note that hauling a vessel for winter storage to "dry out" will not significantly, if at all, lower the trapped moisture in the laminate unless all gelcoat has been removed.

The objective of the fiberglass blister repair is to preserve or improve the current structural integrity and to prevent any future significant structural weakening of vessel's bottom laminate due to the fiberglass blistering. The objective must also be to balance the life expectancy of the repair and the boat against the cost. It is believed that with the materials and techniques available today, a good barrier coating, under normal circumstances, should last four to eight years and a proper performed relamination may last for the life of the boat.

Cost is a serious consideration for most boat owners and in most cases spending money below the waterline instead of above the waterline on cosmetics and equipment is not a very attractive proposition except possibly for a "racing bottom". Barrier coating is a way of preserving "status quo" and preventing additional damage for a limited period of time, a "temporary repair". Relamination is a repair of existing damage and a way of restoring or maybe even improving original structural integrity. With the right materials used, this is considered a "permanent repair". Relamination costs approximately 1.5 to 2 times as much as barrier coating and is becoming as a very attractive alternative to the old way of repairing with a barrier coating. This is particularly true when considering that relamination also addresses hydrolysis and that the repair often can be delayed for the normal life span of 1 to 2 barrier coat repairs without significantly affecting the vessels structural integrity.

Blisters below the waterline can be divided into three groups: "paint blisters", blisters in earlier applied protective coating or antifouling paint; "gelcoat blisters", blistering of gelcoat with no involvement of laminate; and "fiberglass blisters", blisters involving one or more layers of laminate.

Paint blisters can be considered purely cosmetic and should be treated as such. Blistering of earlier applied protective coating would indicate that the coating is compromised and would need to be renewed for best possible protection of the laminate keeping the objective of the fiberglass blister repair in mind. Coating blisters are 1/16 inch to 1 inch in diameter, most common are 1/16 inch to 1/8 inch in diameter. Blisters can be punctured by light finger pressure and contain a sticky acid fluid (always wear eye protection when opening any kind of blister).

Gelcoat blisters with no involvement of laminate is rarely seen but when seen is most often found to be one layer of gelcoat blistering off another underlying layer of gelcoat. This type of blistering is mostly cosmetic, but can possibly increase the likelihood of fiberglass blisters developing. Gelcoat blisters are 1/16 inch to 1 inch in diameter, most common are blisters 1/8 inch to 1/4 inch. Blisters can be easily punctured with a knife tip. Blisters are "crunchy" and contain a sticky acid fluid.

Fiberglass blisters involving gelcoat and part of first layer of laminate is by far the most commonly observed type of blistering. This type of blistering causes relatively little structural damage initially and repairs can often safely be postponed for several years. However, a wet laminate is substantially less strong than a dry laminate and moisture penetration into the laminate can remove resin between fiberglass strands, accelerating the weakening of the structure over time. Blisters are 1/8 inch to 1 1/2 inch in diameter, most common are blisters 1/8 inch to 1/4 inch in diameter. Some pressure is needed with a knife tip to puncture the blister. Blisters are "crunchy" and contain a sticky acid fluid.

Fiberglass blisters involving one or more layers of laminate leads to rather rapid loss of the structural strength of a vessel's laminate depending on number of blisters and layers of laminate involved. This type of blistering normally calls for corrective action within a relative short time span (1 to 3 years). Blisters are 1/2 inch to 3 inches in diameter, most common are blisters 1/2 to 2 inches in diameter. Blisters can be cut using a knife applying some force. Blisters contain a sticky acid fluid.

Before a repair is undertaken, the laminate should be inspected to determine to what degree the laminate is damaged by blistering and hydrolysis. A "window" should be created in the bottom laminate. This is done by grinding into the laminate layer by layer until good laminate is found. Each layer is measured for moisture, hardness (barcol) acidity and thickness. Layers are also visually inspected for resin and blister damage. Thickness of damaged layers can be expressed as a percentage of overall skin thickness. When the information has been analyzed, a decision can be made as to whether any repairs are needed at the present time. If a repair is deemed necessary, a decision has to be made as to barrier coating or relamination taking into consideration the use of the vessel and expected term of ownership verses cost.

A fiberglass blister repair commonly consists of an applied barrier coating to prevent the water from entering the vessel's bottom laminate. None of the presently used barrier coats are 100% water tight and water can, molecule by molecule, penetrate through the created membrane into the vessel's laminate. Microscopic cracking of the barrier coat may also occur due to lack of reinforcement from fiberglass strands again causing water to reach the laminate. Consequently a fiberglass blister repair using barrier coating is not a permanent repair but needs to be renewed after a period of time.

Based on experience and observations, the following basic steps may be taken to assure a satisfactory fiberglass blister repair with maximum life expectancy. The below outlined procedure is for illustration purposes only and may vary between repair facilities.

1. All gelcoat should be removed from below the waterline. This prevents blistering from reoccurring in the interface between the gelcoat and the first layer of laminate, by far the most common area where blisters are seen. The removal of gelcoat also promotes drying of the laminate.

2. The vessel's bottom laminate should then be dried to an even moisture content, comparable to that of the vessel's topsides. On a Sovereign Moisture Master Meter, moisture content should not be more than 5% on the A scale (this is not the actual moisture percentage in the laminate, readings are for comparative purposes only). The reason for drying is two fold. The less moisture that is trapped in the laminate, the more water molecules are needed to pass through the barrier coating before enough pressure builds up to form new blisters. If the laminate moisture content is too high, many of the barrier coatings used will not cure or adhere properly. This often results in blistering of the barrier coating itself or total failure of the bonding of the barrier coating.

3. Wash the laminate after drying to remove any solids and contaminates that might have reached the surface of the laminate after the drying process. This washing can be plain water or an alkaline solution. If an alkaline solution is used, Ph testing should be performed after washing to make sure the alkaline solution has been completely removed. Laminate should be dry before proceeding.

4. The entire below waterline surface should be sealed with one to two coats of thin resin. This resin should penetrate between any loose fibers and into any pores left in the surface of the laminate from removal of the surface, helping to fill and seal as many voids as possible and to create a good bond for the products subsequently applied. The bottom should then be faired with a compound containing non-water absorbent filler.

5. When fairing is completed, barrier coating should be applied to the bottom following the product manufacturer's instructions; however, no less than three coats (not counting coats applied before fairing) should be applied whether the coating is brushed, sprayed, or rolled. Anything less than three coatings will not guarantee complete mechanical coverage. To insure sufficient coat thickness throughout the vessel's bottom, it is suggested that not less than five coats be applied with more being better. If sanding is used or called for between coats, the number of coats may have to be increased.

A more radical and in general much longer lasting approach to repairing fiberglass blisters is to remove all damaged bottom laminate, then laying up new layers of laminate using epoxy or vinylester resin (laminate made with both of these resins have been shown to be much less likely to blister than polyester resin). This repair method has now been proven for a sufficiently long time to almost be labeled as a permanent repair. A theoretical possibility exist of blisters eventually forming in the interface between the different resin types or in the old laminate. Relamination of vessel's bottom is in general only suggested by Hartoft Marine Survey, Ltd. when fiberglass blistering is seen involving more than one layer of laminate or when severe hydrolysis has taken place.

The procedure for relamination follows that of barrier coating closely except for laying up of laminates as needed between step 4 and 5, however then the fairing step is often postponed until after the lamination is completed.

When a decision has been made to repair a vessel's bottom a number of additional considerations are needed. The approach to the repair as suggested by the chosen repair facility should be checked against the above outlined procedure and a resin/coating system should be selected. It is strongly recommended that the resin/coating system to be used is one with which the repair facility is familiar and has a positive experience in applying. A large number of barrier coating systems from different manufactures are available today; however, reliable records of effectiveness of the repairs made in the field with any of the systems are poor, making specific suggestions difficult.

A number of the resin systems are well documented and supported by their manufactures. Not all of the available products are compatible. It is strongly suggested that products from one system not be mixed with products from another system unless thorough testing is first performed. Of all the systems available, the epoxy resin systems appears in theory to be the most desirable. It should be pointed out that epoxy systems require very controlled environments and rather precise techniques during application, which might turn out to be a very limiting factor when used in the normal boat yard environment. Vinylester resins have been gaining popularity as a barrier coating and as a resin for use in relaminating, due to their ease of working and their much reduced sensitivity to environmental factors, they appear to work very well in the boat yard environment but under laboratory conditions they do not show quite the outstanding characteristics of the epoxy resins. The failure rate of vinylester resins is at present by far the smallest of the commonly used materials making their use very attractive.

Regardless of the system used it is suggested that to achieve the best possible curing and to lessen the chance of contamination, a controlled environment should be created around the vessel when coatings are applied. This can be in the form of a plastic tent with temperature and humidity control or the vessel can be placed inside a controlled building. Again, it should be pointed out that a repair facility should be chosen which is familiar and experienced with the desired coating product and procedure.

There appears to be no advantage to treating fiberglass blisters on an individual bases except possible pressure relief by puncturing blisters. Any other approach can at best be considered cosmetic only. When fiberglass blisters are observed on a vessel's bottom, a determination should be made as to the severity of the blistering. If only a few scattered blisters are seen in the bottom involving gelcoat and portions of first layer of laminate it is suggested that no immediate corrective action be taken but that the blister condition be monitored at subsequent haul outs by the "window" process.

If fiberglass blisters are observed involving two or more layers of laminate or severe hydrolysis has taken place, it is suggested that the overall structural condition of the vessel be evaluated and balanced against the use (i.e. "inshore" or "offshore") and corrective measures be taken within a reasonable time period as outlined above.

[ScottMeilicke]

Thanks Minaret, all good info. This has been a very interesting educational process, but I wish I was reading this thread about someone else's potential boat. The Hartoft report was sent to me by a friend, and a good read generally agreeing with the first article linked. I was hoping the first article you pasted in was going to talk about structure, integrity of the GRP, hardness tests, etc., as the hull wen through varying stages of hydrolysis, hopefully to make me feel better!

The engineer in me wants to take the hull down slowly, measuring and analyzing as I go - what could be more fun than that? However the sailor in me just wants a well found boat, and go sailing with the family so we can get the crap scared out of us in heavy weather while heading down the coast.

We are off to Port Townsend today, hopefully the sea air will improve my outlook on this one. maybe I will find a good beer and conversation to boot!

Again, thanks to each and all of you for posting, it has been technically and emotionally helpful.


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[ScottMeilicke]

I don't think I have shared our cruising plans in this thread. We plan to sell our house (on the market now), get the boat, make safety improvements and learn the boat this summer, then hire a captain to help us sail down to San Fran this Fall. From there we would wander down the coast and into MX on our own.

If we go forward with this boat, we would have the rudder fixed, get new rigging and address the other odd safety issues, and do the bottom job in a year or so. We plan to be back in the PNW within two years so my daughter can finish high school, so possibly we would do it then.

Is it wrong to wait for 1-2 years to address this?


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[ScottMeilicke]

Originally Posted by Tayana42

Okay, the boat has blisters. Why blame it on people from Bazil?


S/V B'Shert

I meant to smile at this post earlier. One must be ever vigilant and well armed with humor in these situations.


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[Cheechako]

Just be sure everything else on the boat is good. Things can kind of dominoe on you. Tanks? Engine? Rudder? Deck core? are all high $ repairs.
Here's an example:
44 foot cutter, 7 years old at time of survey, agreed price $117k:
Survey turned up a lot of deck core issues etc. After a yard estimate of $21k to repair just that problem we settled on a $65k selling price in lieu of $117k. That was my final offer and I explained the many reasons including time lost to the owner.
How did it turn out?
-Yard fees ended up $42k (I ended up painting the whole boat, opening and repairing a wet rudder and filling with light epoxy mix, replacing one fuel tank, and other work including removing bottom paint sanding, epoxying and barrier coat and fresh bottom paint (no blisters) and rebuilding /painting the mast.)
In addition of course I did a lot of other work/upgrades after relaunching.


Bottom line, even though I bought the boat for $65k in lieu of $117k. I ended up with probably $130-135k in it.

[Pete the Cat]

Originally Posted by a64pilot

Mine are in the gelcoat, not the glass. I'm postulating that Gelcoat by itself isn't waterproof and of course will absorb water. If you barrier coat Gelcoat without allowing it to dry out, you may be sealing in the moisture and can get small blisters in the Gelcoat that way.
Now I freely admit I am in no way any kind of composites expert, and would welcome any ideas on my theory from one. My theory may well be silly, but well, who knows?
I've been led to believe by a few that small blisters just in the Gelcoat, are of no great concern, and this from some that would profit from me having them fix them


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I had the "thousand blister" problem on my Tartan 37 about 23 years ago. I went the overkill route and had the thing peeled and actually took a layer of glass off and reglassed and refaired the hull. I dried in a yard for 5 months. Based on what I learned, I would not do it again although I have had no problems. Turned out that the problem was caused by a a "preventive" coating that was put on the hull that sealed water between the gelcoat (you are correct, it is permeable) and the substrate by the PO.
There was no delamination anywhere---including a couple spots where the original glass had not been wetted out adequately----still no leakage! I think that as much damage can be done with sealing a wet hull (seems very possible this is what you are dealing with as well) as "protecting" it from water intrusion. I would be very tempted to sand it to see what is there and see if someone already sealed it. Open it up and let it dry. Last think I would do is slap more Interprotect on it at this point without being sure of what is going on. Thousands of blisters seems like something between the gelcoat and laminate and not something coming out of the laminate itself. FWIW.




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[El Pinguino]

Originally Posted by ScottMeilicke

I don't think I have shared our cruising plans in this thread. We plan to sell our house (on the market now), get the boat, make safety improvements and learn the boat this summer, then hire a captain to help us sail down to San Fran this Fall. From there we would wander down the coast and into MX on our own.
If we go forward with this boat, we would have the rudder fixed, get new rigging and address the other odd safety issues, and do the bottom job in a year or so. We plan to be back in the PNW within two years so my daughter can finish high school, so possibly we would do it then.
Is it wrong to wait for 1-2 years to address this?

If it was me which it isn't and going by those photos and the smell of vineger I would be getting her peeled and hotvac-ed. I think you can get that done in the PNW and going by my experience in NZ maybe $20k and 2 months. The 20k isn't a problem as you have just discounted the price by that amount, yes?

While thats being done you can do all your other work.

Could you go to Mexico and back? I'm sure you could but what if you decide to sell her or stay down there or whatever. A spotty boat a long way from home.

My experience? My spots became a cause for concern when I hauled her in BA in 2009 ( first pic) .... got her stripped and sorted in 2014 just shy of 5 years and somewhere around 13000 miles later. Wish I had been able to do it sooner as she was as ripe as a pear..... and the Aus/NZ exchange rate was a whole lot better.

Why sail around with a scabby bottom if you don't have to?