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-   -   Thermal imaging cameras for checking decks and hulls for moisture (http://www.sailnet.com/forums/general-discussion-sailing-related/95980-thermal-imaging-cameras-checking-decks-hulls-moisture.html)

benesailor 01-22-2013 09:26 PM

Thermal imaging cameras for checking decks and hulls for moisture
 
Here's the question.
Has anyone out there ever used a infra-red/thermal imager to check there hull, rudder and deck before? I don't believe i've ever heard of a surveyor using one.

I was walking thru the engineering department the other day and they had this cool looking gun/gizmo sitting there. It looks like a radar gun a cop would use.
After an inquiry they told me it was a special thermal imager that records a digital feed. They use it to scan walls and roofs for energy leaks. They then take it back to the office and download the feed and use it for anlysis to cut down on energy consumption. I thought this would be the perfect tool to check a boat out for any water absorbtion in the deck and hull!! I had used one years ago to look for roof leaks in flat/built up roofs but it was much, much bigger and quite expensive. Not that this one was cheap; about 10k. The one i used years ago was quite handy identifying where all the moisture/cracks/delamination was under the layers of built up.
They said they would train me up and let me take it for a weekend this spring to test it on the boat; Just don't break it! I think if i use it right at sunset or soon thereafter i could get an accurate reading on all the hot/cold spots on the whole boat.

Then again, i may not want to see the video once done!

Ssshhh; maybe i'm onto something. I'll scan every boat in the marina and charge them $100

Oaksail 01-22-2013 10:02 PM

Re: Thermal imaging cameras for checking decks and hulls for moisture
 
A thermal imaging camera uses infrared radiation to compose an image. Surfaces at different temperature give off different levels of IR. A wet core wouldn't necessarily affect the surface temp of the deck.
A bucket of water will eventually attain the same temperature as the air around it.

deltaten 01-22-2013 10:10 PM

Re: Thermal imaging cameras for checking decks and hulls for moisture
 
Likewise.. and not wishing to hijack; but.....
What about these inexpensive stud-finder?
If they beep when solid background (studs) are found; will they NOT beep when voids/blisters are found? Or are they not sensitive/calibrated close enuff?

I'll have to wait till Spring and uncover day ta find out ;)

PorFin 01-22-2013 10:23 PM

Re: Thermal imaging cameras for checking decks and hulls for moisture
 
Bene,

When we had the survey done on Por Fin, the surveyor used a thermal camera to scan the hull and rudder while the boat was in the slings. Everything checked out A-OK.

Fast forward six months. When I stripped off all the bottom paint, I found (much to my surprise) many, many blisters -- some of which yielded a pretty significant amount of juice. Once it warmed up, the rudder also began to weep a surprising amount of fluid.

Based on my experience, I'd stay away from the thermal camera. About the only useful thing the surveyor found with the camera was a loose screw on one of the breakers on the panel (loose contact which was generating heat.)

YMMV.

hillenme 01-22-2013 11:30 PM

When i had mine surveyed the guy used one of these. He also ran a moisture meter over it, which is what i was interested in. Neither device showed significant moisture so i can't say the thermal did or didn't work per se. There were a few places like the rudder where the meter jumped a little and the thermal device seemed to concur with a lower temp. My confidence in the vessel was based much more on the meter readings and visual inspection.

KnottyGurl 01-23-2013 12:20 AM

Re: Thermal imaging cameras for checking decks and hulls for moisture
 
Quote:

Originally Posted by PorFin (Post 979721)
Bene,

When we had the survey done on Por Fin, the surveyor used a thermal camera to scan the hull and rudder while the boat was in the slings. Everything checked out A-OK.

Fast forward six months. When I stripped off all the bottom paint, I found (much to my surprise) many, many blisters -- some of which yielded a pretty significant amount of juice. Once it warmed up, the rudder also began to weep a surprising amount of fluid.

Based on my experience, I'd stay away from the thermal camera. About the only useful thing the surveyor found with the camera was a loose screw on one of the breakers on the panel (loose contact which was generating heat.)

YMMV.

Did they pressure wash the hull prior to scanning the hull in the slings, was it still wet.
Do you remember what the temperature was, these can all effect the scan.

kd3pc 01-23-2013 08:49 AM

Re: Thermal imaging cameras for checking decks and hulls for moisture
 
Quote:

Originally Posted by benesailor (Post 979701)
Here's the question.
Has anyone out there ever used a infra-red/thermal imager to check there hull, rudder and deck before? I don't believe i've ever heard of a surveyor using one.

I was walking thru the engineering department the other day and they had this cool looking gun/gizmo sitting there. It looks like a radar gun a cop would use.
After an inquiry they told me it was a special thermal imager that records a digital feed. They use it to scan walls and roofs for energy leaks. They then take it back to the office and download the feed and use it for anlysis to cut down on energy consumption. I thought this would be the perfect tool to check a boat out for any water absorbtion in the deck and hull!! I had used one years ago to look for roof leaks in flat/built up roofs but it was much, much bigger and quite expensive. Not that this one was cheap; about 10k. The one i used years ago was quite handy identifying where all the moisture/cracks/delamination was under the layers of built up.
They said they would train me up and let me take it for a weekend this spring to test it on the boat; Just don't break it! I think if i use it right at sunset or soon thereafter i could get an accurate reading on all the hot/cold spots on the whole boat.

Then again, i may not want to see the video once done!

Ssshhh; maybe i'm onto something. I'll scan every boat in the marina and charge them $100


You would have to DO EVERY boat in the marina to pay for the gear ($50K and up).....hahaha

these systems, when used in the proper way by trained people, show quite a bit of information. But just like a moisture meter, improper use, calibration or cheap gear, will return poor results.

Just another tool in the box for people to assess condition of things that they can not see in to. Non-destructive evaluation (NDE) is an awesome career path, but in the case of recreational boats, You need to understand how wet stuff holds "heat" longer than dry stuff and how that parlays in to actionable information.

canadianseamonkey 01-23-2013 09:41 AM

Re: Thermal imaging cameras for checking decks and hulls for moisture
 
Some surveyors are using these guns. There's another thread about it if you search.

Frogwatch 01-23-2013 09:50 AM

Re: Thermal imaging cameras for checking decks and hulls for moisture
 
Why would a thermal imager detect water unless the water was at a diff temp than the surroundings?
OTOH, I have always wanted to try using microwaves the either measure water in a hull or to drive it out of a hull by heating it. One could use microwave backscatter from the water to measure it.

For very expensive composite materials, I have just written a proposal to use x-ray backscatter to image water intrusion in composites. Yes, it would work for boats too (It is intended for aircraft components). However, the detector alone costs well over $25,000, the x-ray source over $10,000, software needed, shielding etc.

jimgo 01-23-2013 09:57 AM

Re: Thermal imaging cameras for checking decks and hulls for moisture
 
I'm with the others, above; I don't see how a thermal imaging camera would do anything for you. On a house, you heat it or cool it (internally) and after there is enough time for the interior to reach some approximation of stasis, you scan the outside to look for places where there are temperature differentials (this allows you to, for example, see where the insulation was left out of a wall). But on a boat, you a) don't have an internal, consistent heat source, and b) you aren't really concerned about heat loss. I'd be really curious to see what the guy with the gun sees. Is he looking at the exterior of the boat and looking for areas where the hull, having been heated by the sun, is different temperatures?

I would think an ultrasound imager, like they use on pregnant mothers, would be a better choice for nondestructive testing. It would "see" differences in density and allow you to visualize the problems inside the hull. Of course, you'd have to buy the ultrasound machine, train the operator, and then pay the operator to stand there and scan the entire hull. With the 6-8" wide transducers that I've seen, scanning a 30-40' boat's hull would be a LONG process!


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