Adding to the "Wet Core" Tally

[DaveInRI]

Just passing along for posterity... I’m in the market for a used 22 cruiser, and I looked one over today that’s for sale and brought a moisture meter. Red lights and fast beeping— which indicates greater than 70% moisture— all across the transom, gas tank area, cockpit, aft sole in the cabin, and the foredeck. Only visually suspect places were transom & gas tanks; the rest looked and felt solid! I did get dry readings in all places not near those places. I could press into the floor near the gas tanks with my foot (no barefoot to feel flex necessary). So, I’m adding this to the list of known issues and encouraging people to check their own, any for sale, etc., and rebed your hardware. I’ve read every post on C-Brats and FB about this, and it seems there are some who don’t think it’s common or an issue, so I'm just helping the unofficial survey (that's 1 out of 1 for me).

 

[thataway]

Dave, I have to assume that you have been well trained as a marine surveyor to give this severe condemnation of a boat.

There are multiple issues with moisture meters unless you are specifically trained. From what you are saying is that multi surfaces had failed cores to the point you could deflect the inner surface of the hull by pressure of your foot!

How long have you been using moisture meters to "test" boats?

How many other boats have you used moisture meters on?

What moisture meter were you using?

What calibration block did you use?

Had the boat been recently washed, or stayed out in the night without covers, and had been exposed to dew?

How far from metal objects was the moisture you noted?

To have the degree of moisture you described, the boat would multiple failed areas. Did you use a phenolic hammer or similar to tap out for areas of delamination?

What are your views on David Pascoe's book and articles on Moisture meters?

How about Rod Collins' article on moisture meters?

How about the Practical Sailor article By Darrell Nicholson - Published: August 4, 2000 Updated: November 6, 2019?

I am going to challenge your

I’ve read every post on C-Brats and FB about this.

I have no idea how many hundreds of articles you have read on C Brats. There are 1098 threads in the CBrat search engine on "laminate moisture" alone. I have written posts on the subject where those search words were not present. Note I emphasized "threads", since many of these go for many posts.

Yes, moisture can be an issue. I am not an "expert" on the moisture meter but I have been using them for many years, and consider my knowledge somewhat beyond many accredited marine Surveyors. I have a good knowledge of the physics, and physical conditions, plus "pathologic" boat conditions with moisture and delamination, which I have been studying (going back to the 1960's) with osmosis in boats (Including doing destructive testing on 25 boats after Hurricane Ivan) to develop new ultrasonic instrumentation to measure the degree of delamination and hull failure. I have also studied the core samples of several high end major manufacturers where there was a wet core which took over a year to dry out--and over $100,000 of labor and materials.

The biggest problem I have seen is in some of the 25's. This involves not only the obvious cockpit delaminations and moisture failures, as well as the complete loss of integrity on the hull under the fuel tank, with probably dissolving of the inner layer of resin from the attack of ethanol in the leaking fuel. Also delamination/destruction of the bottom core of the aft cabin main bulkhead.

There have been a few 16's & 22's where water damage was extensive. I find that many of these boats were in places where there was a core penetration. But the solution (after repair) was not rebidding--for if you have studied the issue, it would be to remove the screws and deck penetrations and screw if possible, and put in a solid epoxy plug to screw into, after removing any damaged nearby core. Some places where there are bolts thru a cored area, the material around the bolt, hatch, anchor windless, etc is to remove the nearest 1/4" or so of core; seal the balsa with neat epoxy and then put in a thickened epoxy plug, and rebore the hole, not just "re-bed" hardware.

 

[thataway]

One other thought--I failed to note in the above: That is many of the extensive failed core boats had been in many freeze thaw cycles environments out of doors. Had the boat he tested been exposed to such conditions?

I will wait until DaveInRi responds with what moisture meter he used, before going into some of the issues with various meters.

 

[ssobol]

For my own edification, can someone describe how moisture meters for boats work? I am curious how they detect moisture on the other side of solid gelcoated FG.

 

[DaveInRI]

Just adding to the tally, not relitigating kerfs and capacitance and drill-fill-drill (implied in my rebed verbiage, due to context). Relative moisture as an initial screening tool is still helpful, as is “I can press the deck down with my foot.”’ No tapping needed, there’s an issue here which I do not want to pay for in my search. For someone who paid and continues to educate people about (in an ironic 1000+ threads, yet no, there’s no issue) fixing this product, I am surprised by your aggressive posturing. I did nothing personal to you, I’m just a long time follower of the group, finally ready to buy, concerned about water intrusions, and the very first one I check (owned by one person, an intelligent Cbrat with 300+ posts over 20+ years, a rendezvous goer, etc), and the center of the cockpit floor car from metals is soft and high water content relative to baseline areas? That’s notable and worth sharing. Thanks for your reply??

 

[DaveInRI]

*far

Perhaps I should also add that I’m still looking for and excited about buying a 22 cruiser. This was not a hit job, just a head shaking “gotta be careful out there folks” post.

 

[robhwa]

*far

Perhaps I should also add that I’m still looking for and excited about buying a 22 cruiser. This was not a hit job, just a head shaking “gotta be careful out there folks” post.

Dear DaveInRI; I have been measuring moisture in various trees (wood) and soil as part of my profession for many years. I was a scientist, not a marine surveyer, but do have many moisture detectors, including a Tramex Skipper plus that I use as a tool for boats. I've also tried it to compare to penetrating detectors for wood and find it seems to work OK, with caveats. Realistically, I think using a tool that relies on measuring dielectric constant of material a distance from the emitter and detector for absolute measurements of moisture has serious problems. It is better to imbed the transmitter and detectors in the substance. Not generally possible for boats, of course. Also, any metal in the pulse field will affect results. The absolute best method would be to do a "test coring" by drilling into and sampling the balsa. That said, it sounds to me like you got some useful information, particularly from comparing the physical properties (i.e. soft spots vs hard spots) of readings that tested high moisture to those that didn't. If I were to purchase another boat, particularly with today's prices, I would probably hire a marine surveyer to help me, but I would also do as thorough a job on evaluating it as I could myself, tapping, pressing, and measuring, even after they gave a clean bill of health. In my opinion, of particular help would be comparing known problem areas (i.e. around the gas tanks) to less problematic areas. This seems to be how you approached your evaluation. Good luck to you in finding the boat of your dreams. You certainly live in a storied area for this.

 

[DaveInRI]

Hi. Yes, I was going for relative measurements (dry vs not dry), and probably should not have listed the percentage as I know it's not accurate given the materials (ie, I didn't believe it was 70, but I did believe that there was a lot more water in some places than others. I mentioned the 70+ because, if I were actually using it in straight hardwood, that's what would've correlated to the end of the scale, which it reached). In some areas it was dry, others higher, and several very wet. This relative comparison, and there were discrepancies near various places with metal (which obviously skews a capacitance meter)-- "slightly more than dry", "slightly more than dry", "a little wet", "beep beep beep very wet", back to other areas (eg, certain bow rail/stanchion inserts), and so on. Or, a large area of the cockpit floor, a few feet from anything else, not over a trailer component or bunk, dry to my fingers on the surface (re: dew etc), and "beep beep very wet" and then in other areas, a bit higher, not that. This was an indicator "screening", not a diagnosis. To me, that was all I was looking for in a pre-survey "check it out". Then, if things seemed within reason, I was going to hire a surveyor familiar with cored boats, etc., and take things a bit further. I'm aware it wasn't an ultrasound, but when you can see it, feel it, and "halfway decently confirm it", I didn't need to go further. I, personally, am not interested in a core project. Many here are, and that's good because it keeps the boats "still on the road". But there are prospective buyers with real concerns, both here and on various other groups (Facebook, Downeast, The Hull Truth, Rosborough, etc.), that I felt it valuable to mention this for posterity's sake, for when someone else like me comes along and wants "more data". I'm in New England, the boat was used (and well loved) meaning not a new one (old cars, old boats, old bodies-- all will have some issues), was kept under a tarp during the winter, and it unfortunately has some cancer that yes can be fixed but not by me. The degree of wet beyond "not dry" is not important to me, in my situation, it's a hard pass. I don't need to know the specific percent, or really anything else beyond "there's water inside where there shouldn't be". Doesn't have to be drilled, core sampled, weighed, ultrasounded, tapped w/ the right kind of hammer by someone who knows how (it's not just knocking on it to find a stud), etc., it's a binary decision for me personally.

 

[thataway]

Nothing personal to you Dave. But you failed to answer most of the questions I posed. For a very specific reason--what moisture meter did you use? All of the other questions were relative to your condemning the boat you examined, and to proper use of a moisture meter. I believe that there are lot of "lessons" for all of us in how to, and what to use in determining excessive moisture in a layer of fiberglass and or delaminated core.

Unfortunately the majority of marine surveyors did not want to spend a couple of thousand dollars and a couple of days learning how to use a system which would give an excellent profile of the state of the core, including quality of bonds to the glass above and below, as well as assessment of moisture in the core.

To answer ssobol in part (I suspect that he knows the answer)
is this excellent article by David Kerr, NA. Basically measure capacitance. The answer to the question ssobol is a simple "Maybe" it reads a wet core. Reading the articles I mentioned in my post above, gives a good overview of use of the moisture meter.

For those who want to devolve deeper into the subject the links are: Rod Collins, How to Marine.

David Pascoe Yacht Survey.

Article in Practical Sailor, updated.

Since I started this reply (and had breakfast) there have been a number of other posters who have contributed. This was the goal, to open a discussion about the (faults-and pluses)- use of a generic big box store (Roybi or General, DeWalt etc $30 to $50 meter vs the $635 for the Tramex or the $220 for the Electrophysics TC33. Apparently DaveInRi used one of the generic units. The clue was red lights and 70% moisture readings.

robhwa, Dave Gerr addresses this core issue,

, drill a pair of tiny (5/32”) holes and use a two-pin, DC-resistance meter in the holes.

. However I suspect most of us do not have such a meter (although I suspect that it would be very easy to jury rig one) nor do folks selling their boats will allow an unknown (to them) person drilling any hole into the floor of their boat. Some owners even have been known to refuse to have a screw removed to give an idea of the core status.

Finally, Dave, I would appreciate your interrupting the statement you made:

For someone who paid and continues to educate people about (in an ironic 1000+ threads, yet no, there’s no issue) fixing this product, I am surprised by your aggressive posturing.

I do appreciate your answers, The goal is to educate as much as possible as many boaters as possible about best practices in diagnosis and repair of boat defects. I believe I have been the driving advocate for the epoxy plug or equivalent long before the internet was around. Although I started working in fiberglass in 1952, I didn't build a large boat (38') until 1979 and employed backing plates and / or epoxy cores areas in all deck fastenings in that boat (Plywood deck core).

Addendum: Ultrasound has limited use in the boat survey for most. What we developed was an instrument "cheapened" to be affordable and easy to use for marine surveyors using Pitch and Catch ultrasound testing. These bond testers are used daily by NASA, US military and the airline industry.

There are comparable instruments available thru Olympus or NDT Solutions Huntington Beach which are out of the price range of most marine surveyors, which will profile the core of a delaminated area.