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Discussion Starter · #1 ·
I recently took a chance on a Reliance 44 with a couple of issues. The issue here that I'm seeking advice on is the wet/delaminated balsa core. The photo shows one area (about 5 -7 ft2) on the starboard deck that was definitely delaminated. Another area of about 20 ft2 is around the windlass at the bow, although I haven't opened that up yet.

Having dug into the area pictured, it became clear that although the area beyond the cutout was not delaminated, it was quite wet. Also, I do know from the survey that the moisture readings on the rest of the deck is hit or miss when it comes to moisture. I want to make this right for the long haul, so I'm looking for comments or suggestions on the options I'm considering:

1. Remove the entire top skin and replace the entire core (wet or not) with a synthetic core material. Not including painting/resurfacing (which I was going to have done anyway) this would cost about $5,000 in materials... mostly the new core.

2. Remove the entire top skin and replace the rotten/delaminated areas with synthetic core. Leave the remaining balsa in place, but keep the top off through the winter to let it dry, then close it up in the spring. Cost of this option is about $1,500... $500 in materials, and an extra $1,000 for storing inside vs. outside (I live near Rochester, NY).

3. Remove and replace delaminated areas... take my chances with the remaining wet core. Cost is about $500.

Fortunately I can do the work myself and I'm willing to spend the money to get it right, but I also want to be smart with my time and money. Thoughts?
 

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I recently took a chance on a Reliance 44 with a couple of issues. The issue here that I'm seeking advice on is the wet/delaminated balsa core. The photo shows one area (about 5 -7 ft2) on the starboard deck that was definitely delaminated. Another area of about 20 ft2 is around the windlass at the bow, although I haven't opened that up yet.

Having dug into the area pictured, it became clear that although the area beyond the cutout was not delaminated, it was quite wet. Also, I do know from the survey that the moisture readings on the rest of the deck is hit or miss when it comes to moisture. I want to make this right for the long haul, so I'm looking for comments or suggestions on the options I'm considering:

1. Remove the entire top skin and replace the entire core (wet or not) with a synthetic core material. Not including painting/resurfacing (which I was going to have done anyway) this would cost about $5,000 in materials... mostly the new core.

2. Remove the entire top skin and replace the rotten/delaminated areas with synthetic core. Leave the remaining balsa in place, but keep the top off through the winter to let it dry, then close it up in the spring. Cost of this option is about $1,500... $500 in materials, and an extra $1,000 for storing inside vs. outside (I live near Rochester, NY).

3. Remove and replace delaminated areas... take my chances with the remaining wet core. Cost is about $500.

Fortunately I can do the work myself and I'm willing to spend the money to get it right, but I also want to be smart with my time and money. Thoughts?
#2 seems like the way to go if you can truly keep the boat dry all winter. Cost effective, and you'll still be able to remove all the problem areas.

#1 would be the complete proper way to go, but it's debatable if you really need to go that far. If it were me I'd go #1 but I go overkill on projects and in hindsight it's not always needed (just desired).

#3 is a bad option.
 

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Discussion Starter · #3 ·
Thanks, I agree with your comments. One other thought I had in favor of #2 was that if I did store it outside I would still need to have it shrink wrapped, which I can avoid being inside.
 

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Thanks, I agree with your comments. One other thought I had in favor of #2 was that if I did store it outside I would still need to have it shrink wrapped, which I can avoid being inside.
I dunno, with shrink wrap you have core trying to dry out under cover. Might be humid in there and not dry as good as you'd like. Probably work with some sort of active ventilation though.
 

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There are issues with foam core just llike balsa, different problems but problems all the same. Not sure I would actually say either is better.
Pick your poison I guess.
I think I would tarp before shrink wrap, I've seen a couple of shrink wrapjobs that were just a little too well done. Boat didn't breath over the winter and developed mould. Depends on who does the shrink wrap.
A good tarp job you could get airflow over the areas, even well below 0 things will still dry.
 

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There are issues with foam core just llike balsa, different problems but problems all the same. Not sure I would actually say either is better.
Pick your poison I guess.
I think I would tarp before shrink wrap, I've seen a couple of shrink wrapjobs that were just a little too well done. Boat didn't breath over the winter and developed mould. Depends on who does the shrink wrap.
A good tarp job you could get airflow over the areas, even well below 0 things will still dry.
I never said there are no issues, only said that it is much more easy to repair even if you probably have to resort to professionals with the right material.
 

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Uh pretty much the same process, cut off the top or bottom laminate, replace the bad core then re-glass. I fail to see how one is easier when you have to do the exact same process to replace either. If anything balsa is an easier material to work with.
 

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Uh pretty much the same process, cut off the top or bottom laminate, replace the bad core then re-glass. I fail to see how one is easier when you have to do the exact same process to replace either. If anything balsa is an easier material to work with.
No, if the core is of good quality: they open several holes on the hull for the water to come out, then introduce on all the holes tubes that will blow hot air (for several days) and when the hull is bone dry they inject epoxy under high pressure to fill all the voids. I saw the process being done in good quality shipyards.

That is impossible to do with a balsa core because the balsa will be rotten.
 

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If it's end grain balsa core, you may find its not nearly as "wet" as you may think. The way the material is usually laid up, it has "channels" where the core wets/rots, and it prevents further spread of the water, it really does not wick like you'd think. For sure remove larger areas where it has delaminated... remove back a significant distance from the delamination of core...

Using synthetic core is good I guess, but if you do it right, then doing balsa core again is fine too. One must flex out the balsa and paint it back with resin before laying it back in, and once again, the balsa will only wet out in chunks and usually only if the skin is compromised. From your picture it looks exactly as the core on my S2.

Identify the wettest spots... dig, remove core if its soaked... leave it breathe for a while. Recore where you can, then seal it all back up...

I think I am saying more than #3, but less than #2 with lots of aggressive removal of the wet stuff. I think you'll find that its not real wet except around the obvious areas... since you are going to redo the whole deck anyway, you can drill pilots all over to find the true wet spots, and pretty much the heck with the meter.
 

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Boston Whaler has been using a closed cell foam core for more than 50 years and to my knowledge, they've never had a problem with this. It's an adhesive foam that is injected between the inner and outer hulls. There are other forms of cores other than foam, though. Many powerboat manufacturers began using a honeycomb, fiberglass core for the transoms about 30 years ago, and thus far, they've held up extremely well. Prior to this they used multiple layers of marine plywood, which eventually rotted.

On my Morgan 33 OI, I discovered a wet spot measuring about 6 X 8 feet that extended from the mast opening down to the outer edge of the cabin. I had it drilled and filled with excellent results. The wood had not begun to rot and was still in good condition, therefore, the vacuum process to remove as much moisture as possible seemingly did a good job. It took about two days of vacuuming before the moisture meter provided relatively dry readings, though. The next step involved injecting two gallons of epoxy, then the holes were patched and the entire area was painted with two part epoxy paint. Finally, this was covered with Kiwi Grip, which provided an outstanding appearance and incredible non-skid finish.

All the best,

Gary :cool:
 

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Boston Whaler has been using a closed cell foam core for more than 50 years and to my knowledge, they've never had a problem with this.
Gary :cool:
When I am asked to survey a Boston Whaler the first thing I tell the client is "weigh it" and check the original specs. A friend had one that weighed three times the original spec. We drilled dozens of holes in it and suspended it from a mast crane over winter, Six months later water was still coming out ..... we scrapped it. I rarely see one that is not sopping wet after a five or six years and I know a couple of hundred SAMS surveyors with the same experience.
 

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When I am asked to survey a Boston Whaler the first thing I tell the client is "weigh it" and check the original specs. A friend had one that weighed three times the original spec. We drilled dozens of holes in it and suspended it from a mast crane over winter, Six months later water was still coming out ..... we scrapped it. I rarely see one that is not sopping wet after a five or six years and I know a couple of hundred SAMS surveyors with the same experience.
yes, you are right about that. All modern core synthetic materials have closed cells. That does not mean that the water cannot enter between the core and the outside and inside composite walls. That means only that it will not enter the core itself, like on a balsa core, and that can make a repair more easy. Of course if it is an old boat and the water is there for many years I would not say that a closed core will resist.
 

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Back in the late 1970s I owned a retail store that sold boats, motors and trailers, as well as fishing and hunting gear. I installed dozens of depth finder transducers on Boston Whalers, mainly the Outrage series, drilled holes near the base of the transom, and never, at any time, saw a single drop of water come out of any of them. Now, most were relatively new boats, averaging less than two years old, so that may have had something to do with it. But, if you look back to that era, that was when Boston Whaler was running a TV advertisement where they cut a 17-foot outrage in half with a chain saw and had people standing in each of the halves. The boat was truly unsinkable! Because of this, the US Coast Guard and many state law enforcement agencies adopted Boston Whaler as their patrol and rescue craft. They were rugged, stable, and even when completely swamped, unsinkable.

As for water dripping out over a period of six months, I kinda doubt that - just doesn't make sense. First and foremost, if that much water, three times the hull weight, were inside the hull, the trailer tires would have blown and the axles bent. And, why on earth would someone drill a dozen holes in the hull of any boat? That makes no sense at all.

I've watched Boston Whalers being manufactured and there would not be sufficient space within the hull for more than a cup-full of water to reside. That foam adheres tightly to both the inner and outer hull shells - it's not just chunks of foam that is inserted. Even the fuel tanks and wiring harnesses were embedded in the foam. If you had to replace that fuel tank, you had to cut the deck out then spend hours digging the tank out of the foam. The foam was injected as a liquid and expanded into every crevice and left no room for anything. The only place water could possibly collect was within a PVC tunnel that ran from the center console to the motor well, which was used to route the engine control cables and steering cables.

The only boats I saw lots of water seeping from had a couple layers of marine plywood for transoms, and when they were manufactured and the bilge drains were installed, they were merely a copper sleeve inserted in a hole drilled at the base of the transom with a large flat washer and nut in the bilge. Salt water eventually rotted out the copper tubing and because no one ever sealed the hole that drilled, the water intruded into the plywood. I drilled a couple holes in the transom base of a very popular model of boat one afternoon to mount a kick up bracket and water ran out of those holes for two days before it stopped. But, it was just a trickle during the entire time.

Nearly all powerboat manufactures have long since switched to honeycomb, fiberglass transom cores, thus eliminating the problem. I wonder when the sailboat manufacturers will finally get around to this? The honeycomb fiberglass cores are lightweight, exceptionally strong, yet still somewhat flexible, and they will NEVER rot! Ironically, when I visited the Pro-Line factory in south Florida, they said the cost was actually less than when they used plywood. And, they also switched to a high density nylon for reinforcement backing inserts for deck items such as cleats, windlasses and rod holders. Just makes sense, at least to me.

Good luck on whatever method you decide upon,

Gary :cool:
 

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So let's talk about Boston Whalers for a moment... Everyone who has ever dealt with them is pretty familure with water saturation of the foam cores. In large part because BW builds the boats using a process called UniBond, where the two molds are glued together, then expanding foam is injected into the void. It's a cheap way to add flotation, and lasts reasonably well. But all of the expanding foams are notorious for water absorption.

Water retention is such a common problem in Boston Whalers that the company even has a long discussion about how to fix it (sometimes works) on their website. Once it gets bad, there just isn't much to do but open the deck and cut out the bad foam.
 

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Check out Pascoes test on foam cores and hydraulic erosion.
I have seen Boston Whaler foam pulverized by hydraulic erosion and the foam they use can absorb huge amounts of water. I believe"closed cell" foam is a relative term only.
 

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While balsa core gets a lot of bad raps, its big advantage is that the water doesn't wick away from the leakage location very easily. Any damage is typically localized unless its major and not taken care of. Most of the other products will allow water to travel easily and a small leak can become a major problem very quickly.
 

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While balsa core gets a lot of bad raps, its big advantage is that the water doesn't wick away from the leakage location very easily. Any damage is typically localized unless its major and not taken care of. Most of the other products will allow water to travel easily and a small leak can become a major problem very quickly.
This is quite simply untrue.
I suggest you google "core balsa deck image". Several of the photos that come up on the first page are of my own boats.
 

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Check out Pascoes test on foam cores and hydraulic erosion.
I have seen Boston Whaler foam pulverized by hydraulic erosion and the foam they use can absorb huge amounts of water. I believe"closed cell" foam is a relative term only.
Bingo!! Don't ask me how much my old 13' Whaler weighed.:eek It was fully saturated to the point that the 40HP motor was having a tough time getting her up on plane. Boat was scrapped back in about 84 when it was simply not cost elective to repair it. How does anyone not know about this issue in the year 2015 is well beyond me....

Me, I still prefer Balsa, done right......
 

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Bingo!! Don't ask me how much my old 13' Whaler weighed.:eek It was fully saturated to the point that the 40HP motor was having a tough time getting her up on plane. Boat was scrapped back in about 84 when it was simply not cost elective to repair it. How does anyone not know about this issue in the year 2015 is well beyond me....

Me, I still prefer Balsa, done right......
I agree ...... if done right. In my experience however, getting it done right by a production builder is unlikely.
 
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