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Thermal imaging cameras for checking decks and hulls for moisture

11K views 18 replies 14 participants last post by  benesailor 
#1 ·
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
 
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#2 ·
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.
 
#3 ·
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 ;)
 
#4 ·
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.
 
#5 ·
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.
 
#7 ·
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.
 
#9 ·
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.
 
#10 ·
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!
 
#11 ·
Thanks for the insight everyone. I'm definitely soaking up the input here.

Since the use of the gun is free I'm gonna try it out and have at the minimum a digital scan of the whole boat to look at and scratch my head for hours. Like i said i have used these before to scan built up roofs for water; so, i have some experience using this type of equipment. That was 20 yrs. ago and it was a SOB crating it onto the roofs. But when a roof is in the 10's of thousands of dollars, its worth it. In addition; i have used the scopes and hand held units for security purposes.

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've been thinking about this. I think My solution will be to crank up the heater inside (on the hard) so i believe i can get a more consistent reading outside. Won't help with the rudder though. (i might be able to place a heat lamp on one side to see how much sinks thru or reflection)

As far as thermal imaging goes; if you've never seen it in action you're missing out. Temperature differentials REALLY stand out. So I'm thinking moisture laden anything in a hull or deck would be at a different temp than it's surrounding area. R-values are different in al types of materials. Thermal imaging is instantaneous as well. If you put your hand on the side of a P/U for 30 sec and walk away i can see your hand print and your footsteps as long as it's within a certain time frame and the weather conditions hold up. If you think this is far out; watch a live video feed from a UAV; it gives a whole new meaning to "smoking is bad for your health". From 35,000 feet it's like someone set off a flare!
It's great for deer hunting too. ;) I've used them for perimeter security at night as well. It wasn't like the gun i looked at the other day though.

I just view this as another tool to use. (along with a moisture meter and hammer) Anything that can highlight any issues before they become major i view as a benefit. Like i said; it's free, so I'm going to take advantage of it before i don't get a chance to.

Thanks benesailor
 
#12 ·
themal imaging would work if you have an heat source aboard. The air or water bubble would come up as a cool spot as it would either act as insulation (air) or taking longer to heat up (water) and would be best done on the hard.

You would probably not have much time to do it.. so best to use an infrared heatlamp and a helper
 
#13 ·
I agree it can't hurt. Like i said my experience was sort of inconclusive, but given the cost of the device and credentials of the surveyor (he'd designed, built and sailed a sub) i assume he wasn't wasting mine and his time. I don't know anything about how it works, but there was a water logged piece of timber on the deck that was white/blue surounded by yellow. Pretty obvious difference. Don't know if it's as simple to say wet end grain core in the hull would have the same effect.
 
#14 ·
i agree.
That's why i think i will get the interior 80 plus degrees and do the outside scan after sundown for the greatest temperature differential. After googling i now see that surveyors are using them.
I can't wait to try it. I think tomorrow morning should be good. It will be about -10F (-23C). If i put a salamander inside i should be able to get a good temp difference??
Just kidding; i'll wait.
 
#15 ·
The use of thermal imaging techniques for assessing marine structures is well documented. You do need to understand the conditions necessary to achieve the heat transfer that is going to reveal the problems. I have several white papers on this subject. Please contact me for more information.

mailto:gary.orlove@infraredtraining.com
 
#16 ·
I own a Flir thermal imager and use it in my surveys. They can provide a tremendous amount of information including delamination, blisters, wet core, sub surface fractures, hot electrical connections, hot spots on exhaust systems and a whole lot more. They are incredibly difficult to use and to interpret. It took me a year of playing with various bits of test panels under varying conditions to feel any comfort with it.

To me, it's just another tool in the bag and I am not certified in thermal imagery. Thermal imagery certification is a long and expensive process but there are level three certified thermographers who are also marine surveyors. There are some free online seminars should you wish more information or you can check out Jack Allinson SAMS AMS & Level three Certified Thermographer website for a lot more info.
 
#17 ·
I have no doubt that I could take an IR picture of a 20# propane bottle 5 minutes after the sun first hits it and be able to tell exactly how much fuel is left*. I know that is not the best use of a $25,000 analysis tool, but it is a start!

By the same token, a pic taken just after the sun hits the boat might also reveal wet spots that would take longer to warm. Or maybe they would warm faster. Either way, I think you would need to do an IR survey when the boat is new and then compare as the years go by. It would be very difficult (I think) to determine which artifacts are from defects and which are simply design/construction.

To avoid having to turn the boat around and wait until the next morning for the other side; you could work on a cool night with a battery of heat lights. Hey, if you've already sunk $25k into a test tool what's few hundred more for some lights!

*The sun will warm the top half (where there is no fuel) much faster than the bottom (where the fuel is keeping it cool); after a while, the whole thing will be the same temp and the level won't be as obvious.
 
#19 ·
Thanks for all the info and ideas. Like i said i just get to use it for the weekend.(well, a couple of weekends) They will give me limited training. None of these guys has ever done a boat. I'm not about to buy a 10k camera for myself; but, i don't mind using it for free!
 
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