moisture meter useful on long-stored boat?

[Buddy_Y]

This winter, I purchased a C&C 30 mk i that has been stored in a dry warehouse in Ontario for 13 years after the death of its owner. My question: after 13 years in dry storage (and it is a good warehouse), I am considering buying/renting a moisture meter to run over the deck, but would that be useful? Even if the boat had wet core originally, would the core not have dried out by now? Should I skip the meter and start drilling exploration holes?

The background.... Thirteen years ago, the PO removed 90% of the hardware from the boat deck, plugged the holes with some basic tar (as a temporary measure for the move, I imagine), and then had the boat trucked from a marina to a warehouse. Then he passed away. All his next-of-kin and the warehouse owner know is that he mentioned that he intended to do unspecified 'work.' My guess: this work might have been prepping to relocate the winches etc to reroute the rigging to the cockpit (which many of the C&C 30 owners eventually do); and/or it might have been a re-drill and re-bed program for the hardware. (But he filled in hardware mounting holes even in places were there was no core, e.g. on cocking coamings where it was just fiberglass, which suggests to me that he was not necessarily targeting core rot.) This 'work' probably wasn't a paint job--the warehouse says the PO would have known they would not have allowed that (the place is cramped and has collector cars stored around the boat).

This winter, I carefully walked the deck pre-purchase (and before freezing temperatures set in), but could feel no soft spots. I always had surveyors for my previous boat purchases, but the rest of the boat was in great shape (bone dry) and the asking price was 'Any offer, just get this out of our lives. As is.' So I took a flier on it. Now that spring has arrived, I'm about to start remounting the hardware. But before I start, I'm not sure if I should give the whole deck a moisture check--for peace of mind at least.

Notably, the 'rapping' approach to listening for hollow spots gives me mixed results. Some areas around the old hardware locations sound slightly deeper timbre than other locations, but the difference is so modest I don't know if it's significant.

[xxxxx]

Where in ON?

I'm sure you can borrow one off a member here--you can borrow mine if you're close by.

[Buddy_Y]

Originally Posted by xxxxx

Where in ON?

I'm sure you can borrow one off a member here--you can borrow mine if you're close by.

It's in Binbrook, near Hamilton. Yourself?

[xxxxx]

Originally Posted by Buddy_Y

It's in Binbrook, near Hamilton. Yourself?

Done and done.

[boatpoker]

Should you decide to purchase a moisture meter (or borrow one) this
may be helpful.

Moisture Meter Mythology

[Buddy_Y]

Originally Posted by boatpoker

Should you decide to purchase a moisture meter (or borrow one) this
may be helpful.

Moisture Meter Mythology

Thanks for the link!

[GordMay]

Originally Posted by Buddy_Y

... Notably, the 'rapping' approach to listening for hollow spots gives me mixed results. Some areas around the old hardware locations sound slightly deeper timbre than other locations, but the difference is so modest I don't know if it's significant.

The deeper timbre 'thunks' probably indicate plywood inserts in deck core (as opposed to general balsa deck core], for factory-installed hardware.
You might be interested in the C&C Photo Album & Resource Center ➥ http://www.cncphotoalbum.com/
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[geoffr]

Your results with a moisture meter may vary and does take a bit of knowledge of the boat & meter.

We had our boat on the hard for 10 years (outdoors) and with our meter we still got some higher readings except for a few places where they were sky high... but they were okay as it was due to the metal structure in the rudders.

Recently we had a deck fitting go which was through core and the meter was pretty much bang on for where the wet core ended. It's also done a very good job of showing a water tight compartment with water in it. So yes they do work.

If your boat had wet core and it dried out it won't show you that... but from my experience I doubt it will have dried out fully.

[Buddy_Y]

Originally Posted by GordMay

The deeper timbre 'thunks' probably indicate plywood inserts in deck core (as opposed to general balsa deck core], for factory-installed hardware.

I like that theory -- it would explain why the sound is different, yet the deck does not demonstrate any softness even under my weight. Thanks!

[Buddy_Y]

Originally Posted by geoffr

We had our boat on the hard for 10 years (outdoors) and with our meter we still got some higher readings... If your boat had wet core and it dried out it won't show you that... but from my experience I doubt it will have dried out fully.

If I had a boat outside on the hard for a decade, I wouldn't be surprised about dampness in the core. But my thought is that 13 years in a good-quality bone-dry warehouse would be a different matter. Time will tell!

[Buddy_Y]

Update: Our forum colleague XXXXX has indeed offered to loan me his moisture meter the next time I head out to the boat. Thanks, XXXXX!

[boatpoker]

Originally Posted by Buddy_Y

I like that theory -- it would explain why the sound is different, yet the deck does not demonstrate any softness even under my weight. Thanks!

The sound will also be different if the plywood is degraded. Plywood
degrades and spreads faster that balsa core in the presence of water.

[rslifkin]

Plywood definitely spreads water faster, but depending on what kind of wood it is, it doesn't necessarily rot faster. I re-cored my bow pulpit (which had a poorly sealed plywood core) last year. The entire thing was soaking wet and the plywood was de-laminating from water freezing in it, but other than right at the point of water entry, it wasn't rotted. And that was after getting wet for 34 years (due to an out of sight exposed edge left during the original build).

[Buddy_Y]

Originally Posted by boatpoker

The sound will also be different if the plywood is degraded. Plywood degrades and spreads faster that balsa core in the presence of water.

Okay, but if the plywood were degraded, wouldn't the deck be soft? When I stand directly on those spots and even bounce my 200 lbs up and down a bit, I don't feel any give underfoot.

[boatpoker]

Originally Posted by Buddy_Y

Okay, but if the plywood were degraded, wouldn't the deck be soft? When I stand directly on those spots and even bounce my 200 lbs up and down a bit, I don't feel any give underfoot.

Maybe ... it depends on a lot of things ... without metering and percussive sounding myself I would not suggest a definitive answer.

PS. "Percussive sounding" is a not quite accurate term. The feel and bounce back of the hammer is as important as the sound which is why we use brass hammers. We don't believe rubber or hard plastic can give the required feedback.