Checking stringers and other pre purchase inspection notes.

S

SeatownLion

New member
Hello all it’s my first post here. I am looking at an ‘84 22’ Cruiser and want to inspect the stringers and core. What is the best way to check, or is drilling pilot holes the only way? Any other dealbreakers? It’s $12k with old Johnson 2strokes so will want a repower and electronics eventually. I’m not afraid of a project and this seems doable unless it’s rotten out.

Hoping I can make this happen.

Thanks!!

Arie

Pics once I figure out how[/img]
 
Hope you can make it all work. They make a infrared type moisture meter, they might not show what the exact moisture level is but they can help you see what may have water.

Rob
 
I would use a cheap moisture meter. I have a Ryobi pin-less. You are comparing areas. Also you can sound out the bottom of the hull either with a phenolic hammer, or plastic handle of a screwdriver.

No stringers as in conventional boats. The 1984 is one of the early models, which has plywood core. Many folks revise the "splash well" to make it more modern.

No C Dory is beyond salvage. That has been proven several times, with both hurricane or going on the rocks. Some owners have replaced almost the entire core of the bottom. A $12,000 C Dory is a unicorn to begin with. If the motors run, all the better.

Yes, you can get a FLIR IR adaptor for your I phone (cheaper than a dedicated IR camera). To get the most of that there has to be selective heating of areas of the hull and then comparisons. Probably technologically beyond what many would want to do. FLIR camera or camera adaptor for I OS or android phone
 
mutski":1r25b4jc said:
How does the FLIR identify moisture? How does one use it?
Click to expand...

The FLIR is mostly infrared spectrum, and records in color, the outline of the object, and various temperatures defined by change of color. Red- to White is very hot, and green to blue is cool. There are various color palettes, and the surveyor can choose. Ironwood, is a commonly used palette. There are temperatures assigned to the limited of that specific picture:

88422905_scaled_324x243.jpg


This photo is lifted off a surveryor's web site: Suenos Azules Marine Surveying and Consulting , and shows cool blistering just aft of the bow thruster. The explanation and more photos are well shown on this web site.

The boat has to be heated enough to show the difference between dry fiberglass/core vs fiberglass laminate or core with water intrusion (cooler).

I have a hand held FLIR scope, and although it is not calibrated, and as sophisticated as a dedicated FLIR camera or adaptor to use with an IOS phone/android phone, it will detect temperature differences enough to show obvious wetness.

We have also done some studies with ultrasonics to identify delamination and wet core laminate. (This was done with non destructive testing gear, but on samples we. had taken from 25 hurricane damaged boats which were going to be scrapped.) We were also able to determine the moisture content of the samples, by weight before and after dehydration in an oven. This testing gear is not available to the public. Surveyors rejected it because it costs a few thousand dollars and requires training to use.

FLIR is also very useful in looking at electric terminals, and seeing if there is excess heating, suggesting increased resistance at that specific point.

I have never "looked" at a C Dory with entirely saturated core. One would need dry core to compare it with on the same boat.

Unfortunately not all surveyors use FLIR. It is a great tool, when used properly. (training, and right equipment are key.)
 
I am a retired firefighter. We used a thermal imagine camera both for building search and for locating hidden hotspots. Or spotting intense heat accumulating at the ceiling. Playing around between calls, we could spot footprints where someone had walked across the parking lot on a cold (Alaska) winter evening, see the studs in the wall (they are colder than the insulated spaces between). I can imagine if a boat changed temperature, you'd see wet spots because they would have a greater specific heat than dry wood. I bet just pulling the boat from outdoors into a heated garage would do it.

The surveyor that did the boat I just bought used ultrasound, and told me the highest moisture content he found was 14%. I'm not sure what kind of ultrasound he used or what data backs it up.
 
Mutski, Great on being a firefighter. Thank you! You have extensive experience with FLIR. There are several ways that heat signatures are enhanced on fiberglass boats. Certainly changing total environments such as the heated barn is great for a small trailerable boat.
 
Thanks everyone I bought the as yet unnamed 1982 ‘22 Classic. Had the original Johnson running and sold it for a paltry $800. Really all it needed was a carb job. Found some transom issues when I took it off, which I will leave for another thread.
 
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