Infrared Imaging of Boston Whaler hulls to find delamination and/or water intrusion.

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Author Topic:   Infrared Imaging of Boston Whaler hulls to find delamination and/or water intrusion.

Jessielove posted 04-08-2012 09:47 AM ET (US)
I came across a marine surveyor that offers as part of his services Infrared Imaging of hulls, and electrical and mechanical systems. I wonder if any of you have had a similar inspection performed either as a part of your normal maintenance or as a pre-purchase survey on a whaler? More specifically, I wonder how effective infrared imaging would be for identifying water intrusion into the foam filled whaler hulls.
Here is a URL to the surveyor's website that has some sample infrared images:
http://www.digitalmarinesurveys.com/page7.html
boatdryver posted 04-08-2012 10:24 AM ET (US)
The use of infra-red technology in evaluating mechanical and electrical systems is one thing, but its usefulness in detecting water intrusion in older, Classic Whaler hulls could be problematic.
It's likely that most older hulls will show more abnormalities than the standard "tap" test. If so, whether I were the buyer or seller, I would hope that the surveyor had a very great deal of experience in quantifying the significance of his findings in a pre-purchase survey. For example, what do infra-red surveys of a series of almost new boat look like, and in the case of a 20+ year old Whaler, at what point do the findings negate a sale?
I hope other members with personal experience with infra-red hull surveys will comment.
JimL
jimh posted 04-08-2012 11:53 AM ET (US)
What thickness of material like fiberglass laminate can infrared waves penetrate?
Teak Oil posted 04-08-2012 05:09 PM ET (US)
I am taking a class right now in which the instructor is an electrician who uses a thermal imager daily at work. He has shown us quite a few examples in the class, and I have no doubt the imager would be able to read the thermal difference of a wet hull vs a dry hull. These machines can have their calibration tuned to detect variations of only a few degrees if desired.
If a wet whaler hull was brought from a cooler storage area into a shop to be tested, I am sure the temp difference of the wet portion of a hull would be noticeable for many hours.
Jim does have a valid point however, in that unless the surveyor had a lot of experience using the camera, especially with the unique construction methods that Whaler uses, the information might not be all that valuable.
False interpretation of the readings might cost you a chance at a nice boat.
andygere posted 04-08-2012 05:16 PM ET (US)
Wouldn't any water in the hull be at temperature equilibrium with the hull materials? What would account for the difference in temperature of entrained water and foam and fiberglass?
A scale is a better tool for determining if a hull is waterlogged.
DVollrath posted 04-08-2012 05:55 PM ET (US)
Two ideas come to mind. The infrared sensor could be used in conjunction with a directional microwave transmitter to heat the weak dipole molecules of any water present. This could produce a thermal gradient sufficient to be detected by the sensor. Or not...
Way out of my discipline here, but it seems like using an ultrasonic detection scheme might be workable as well. Water soaked foam would likely conduct the waves quite differently than dry foam.
Either way, the market for detecting water in the hulls of old Whalers is probably pretty small in any give locale, so it's not clear who would put the resources into developing equipment and techniques. Fun to think about though.
Dennis
jimh posted 04-08-2012 10:39 PM ET (US)
Dennis--I think you just described a moisture meter.
Jessielove posted 04-09-2012 08:12 AM ET (US)
In one of the pictures of a sailboat deck, it appears the surveyor uses the infrared image to identify possible water intrusion areas and then confirms if there has been water intrusion with a moisture meter.
I glean from what I have read about the subject in the past day that if a hull were, for example, to experience the natural heating and cooling cycle between daytime and nighttime, that a waterlogged area would react more slowly than a nearby dry area exposed to the same conditions. A boat stored indoors with a more uniform temperature environment and scanned indoors likely would be much more difficult to interpret the image and may require an auxiliary thermal source to help identify different thermal response rates.
While my initial post dealt with water intrusion, it is also interesting to note some of the electrical temperature imaging photographed. I presume this type of service would require some extended time with a boat’s various electrical circuits closed and the devices in the circuits operating at full capacity. I wonder how much time would be required to achieve full operating temperature in various sizes of conductors and machinery on a typical small boat like a whaler.
kwik_wurk posted 04-09-2012 03:06 PM ET (US)
IR cameras are used all the time to detect moisture in insulation. Now when dealing with thicker media such as fiberglass skins, and experienced user is needed.
IR cameras show pretty pictures and work well with humans because we are such visual beings. Interpreting the results into meaningful information is a different issue. Not slamming the surveyor; just stating there is a difference between knowing enough to be dangerous, and actually knowing the technology well.
Now would I survey my Montauk with an IR certified tech. No, I would rather spend the money towards a new engine.
Jerry Townsend posted 04-09-2012 04:51 PM ET (US)
Infared could work to detect water (a lot of it) in a hull - as it works at a wavelength affected by heat. It does not penetrate a body like X-ray or microwave. In this case, it could work, in part, because water has a higher coefficient of heat - and then retains heat longer than other materials - including fiberglass. In this case, it could work by bringing a boat, setting in the hot sun, for awhile into a cooler area. The water retains it's heat much better than the fiberglas - and areas penetrated by water would appear warmer.
And then it works the other way as well - taking a boat from a shaded area into the hot sun - where the water saturated area will appear to be cooler.
In electronics, infared has been used to detect faulty electrical components - as a faulty resistor or transistor will generate heat because of the added resistance - which shows up on an infared image. ---- Jerry/Idaho
Jeff posted 04-09-2012 08:40 PM ET (US)
When it comes does to it, all old Whalers will have some water in the foam. I would put money on the fact that every single classic whaler that has even been used would show elevated moisture readings somewhere on the hull while using a moisture meter.
Some claim you should weigh the hull to gauge how much water is in there. I say that is a very imperfect science as well. Since Whaler openly admits the published weights were estimates and likely no two hulls ever left the factory weighing the same. That allows for a lot of fudge factor.
I personally like to see a hull float to see if it seems heavy. Yes, that is imperfect as well but, I have found it to be the best judgment tool for myself. If it seems to float well and the water line is falling where I would expect it to, them I am satisfied.
There are all kinds of false-hoods and myths about water and the foam inside the classic Whaler hulls. In fact a large group of professionals still do not know the true details of water in the foam of Whalers nor, what really constitutes waterlogged Whaler hull. When I bought my 22 Outrage I had to have a survey done for a value estimate as I was taking a loan to buy it. The surveyor found two areas of elevated moisture readings. He personally recommend on the phone that he would not buy the boat if it was him because of this. When asked if he had researched, or knew of any specifics about Whaler specific construction methods, about moisture in the foam effecting hull integrity and if those would change the outcome of his opinion he stated he did not. In fact many of the surveyors I have talked to specifically about Whalers, the foam and elevated moisture readings do not seem fully educated on why you would find those readings, as well as how much they do and do not effect the overall true condition of the hull's integrity. Some come right out and say "Well Whaler says they used a closed cell foam that does not hold any water. So, if there is any water in there the hull is likely shot."
So, I guess if that is the case, What is the infrared imagine going to do other than likely stir up more claims of "waterlogged" Whalers. If the infrared imagining can show areas of delamination I could see that as being something of value if you find an area that does not pass the knock test.
Jessielove posted 04-09-2012 10:30 PM ET (US)
Maybe I am missing the point here, but if you or I could see the profile and extent of water soaked foam clearly on a whaler hull, how could that not be a helpful factor in making a decision about a boat as part of a pre-purchase survey?
Granted, if you don't care if the boat is waterlogged or relatively dry, then it would not be helpful, but I think all things being equal many if not most or all of us would choose a comparatively dry hull over a wet hull.
I can also see the value of such imaging to help someone who wished to attempt to dry out a wet hull or replace some wet or damp foam.
I can also envision hull penetrations being quickly scanned to help identify the source of water intrusion. It seems like there could be a many useful aspects to this form of imaging. You would not have to remove a transducer necessarily to determine if the screw holes are leaking.
Again, I am thinking of this from the viewpoint of a surveyor who won't or can't do a more destructive form of evaluation, not from an owner's viewpoint who is free to do as he wishes to the hull.

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Author	Topic: Infrared Imaging of Boston Whaler hulls to find delamination and/or water intrusion.
Jessielove	posted 04-08-2012 09:47 AM ET (US) I came across a marine surveyor that offers as part of his services Infrared Imaging of hulls, and electrical and mechanical systems. I wonder if any of you have had a similar inspection performed either as a part of your normal maintenance or as a pre-purchase survey on a whaler? More specifically, I wonder how effective infrared imaging would be for identifying water intrusion into the foam filled whaler hulls. Here is a URL to the surveyor's website that has some sample infrared images: http://www.digitalmarinesurveys.com/page7.html
boatdryver	posted 04-08-2012 10:24 AM ET (US) The use of infra-red technology in evaluating mechanical and electrical systems is one thing, but its usefulness in detecting water intrusion in older, Classic Whaler hulls could be problematic. It's likely that most older hulls will show more abnormalities than the standard "tap" test. If so, whether I were the buyer or seller, I would hope that the surveyor had a very great deal of experience in quantifying the significance of his findings in a pre-purchase survey. For example, what do infra-red surveys of a series of almost new boat look like, and in the case of a 20+ year old Whaler, at what point do the findings negate a sale? I hope other members with personal experience with infra-red hull surveys will comment. JimL
jimh	posted 04-08-2012 11:53 AM ET (US) What thickness of material like fiberglass laminate can infrared waves penetrate?
Teak Oil	posted 04-08-2012 05:09 PM ET (US) I am taking a class right now in which the instructor is an electrician who uses a thermal imager daily at work. He has shown us quite a few examples in the class, and I have no doubt the imager would be able to read the thermal difference of a wet hull vs a dry hull. These machines can have their calibration tuned to detect variations of only a few degrees if desired. If a wet whaler hull was brought from a cooler storage area into a shop to be tested, I am sure the temp difference of the wet portion of a hull would be noticeable for many hours. Jim does have a valid point however, in that unless the surveyor had a lot of experience using the camera, especially with the unique construction methods that Whaler uses, the information might not be all that valuable. False interpretation of the readings might cost you a chance at a nice boat.
andygere	posted 04-08-2012 05:16 PM ET (US) Wouldn't any water in the hull be at temperature equilibrium with the hull materials? What would account for the difference in temperature of entrained water and foam and fiberglass? A scale is a better tool for determining if a hull is waterlogged.
DVollrath	posted 04-08-2012 05:55 PM ET (US) Two ideas come to mind. The infrared sensor could be used in conjunction with a directional microwave transmitter to heat the weak dipole molecules of any water present. This could produce a thermal gradient sufficient to be detected by the sensor. Or not... Way out of my discipline here, but it seems like using an ultrasonic detection scheme might be workable as well. Water soaked foam would likely conduct the waves quite differently than dry foam. Either way, the market for detecting water in the hulls of old Whalers is probably pretty small in any give locale, so it's not clear who would put the resources into developing equipment and techniques. Fun to think about though. Dennis
jimh	posted 04-08-2012 10:39 PM ET (US) Dennis--I think you just described a moisture meter.
Jessielove	posted 04-09-2012 08:12 AM ET (US) In one of the pictures of a sailboat deck, it appears the surveyor uses the infrared image to identify possible water intrusion areas and then confirms if there has been water intrusion with a moisture meter. I glean from what I have read about the subject in the past day that if a hull were, for example, to experience the natural heating and cooling cycle between daytime and nighttime, that a waterlogged area would react more slowly than a nearby dry area exposed to the same conditions. A boat stored indoors with a more uniform temperature environment and scanned indoors likely would be much more difficult to interpret the image and may require an auxiliary thermal source to help identify different thermal response rates. While my initial post dealt with water intrusion, it is also interesting to note some of the electrical temperature imaging photographed. I presume this type of service would require some extended time with a boat’s various electrical circuits closed and the devices in the circuits operating at full capacity. I wonder how much time would be required to achieve full operating temperature in various sizes of conductors and machinery on a typical small boat like a whaler.
kwik_wurk	posted 04-09-2012 03:06 PM ET (US) IR cameras are used all the time to detect moisture in insulation. Now when dealing with thicker media such as fiberglass skins, and experienced user is needed. IR cameras show pretty pictures and work well with humans because we are such visual beings. Interpreting the results into meaningful information is a different issue. Not slamming the surveyor; just stating there is a difference between knowing enough to be dangerous, and actually knowing the technology well. Now would I survey my Montauk with an IR certified tech. No, I would rather spend the money towards a new engine.
Jerry Townsend	posted 04-09-2012 04:51 PM ET (US) Infared could work to detect water (a lot of it) in a hull - as it works at a wavelength affected by heat. It does not penetrate a body like X-ray or microwave. In this case, it could work, in part, because water has a higher coefficient of heat - and then retains heat longer than other materials - including fiberglass. In this case, it could work by bringing a boat, setting in the hot sun, for awhile into a cooler area. The water retains it's heat much better than the fiberglas - and areas penetrated by water would appear warmer. And then it works the other way as well - taking a boat from a shaded area into the hot sun - where the water saturated area will appear to be cooler. In electronics, infared has been used to detect faulty electrical components - as a faulty resistor or transistor will generate heat because of the added resistance - which shows up on an infared image. ---- Jerry/Idaho
Jeff	posted 04-09-2012 08:40 PM ET (US) When it comes does to it, all old Whalers will have some water in the foam. I would put money on the fact that every single classic whaler that has even been used would show elevated moisture readings somewhere on the hull while using a moisture meter. Some claim you should weigh the hull to gauge how much water is in there. I say that is a very imperfect science as well. Since Whaler openly admits the published weights were estimates and likely no two hulls ever left the factory weighing the same. That allows for a lot of fudge factor. I personally like to see a hull float to see if it seems heavy. Yes, that is imperfect as well but, I have found it to be the best judgment tool for myself. If it seems to float well and the water line is falling where I would expect it to, them I am satisfied. There are all kinds of false-hoods and myths about water and the foam inside the classic Whaler hulls. In fact a large group of professionals still do not know the true details of water in the foam of Whalers nor, what really constitutes waterlogged Whaler hull. When I bought my 22 Outrage I had to have a survey done for a value estimate as I was taking a loan to buy it. The surveyor found two areas of elevated moisture readings. He personally recommend on the phone that he would not buy the boat if it was him because of this. When asked if he had researched, or knew of any specifics about Whaler specific construction methods, about moisture in the foam effecting hull integrity and if those would change the outcome of his opinion he stated he did not. In fact many of the surveyors I have talked to specifically about Whalers, the foam and elevated moisture readings do not seem fully educated on why you would find those readings, as well as how much they do and do not effect the overall true condition of the hull's integrity. Some come right out and say "Well Whaler says they used a closed cell foam that does not hold any water. So, if there is any water in there the hull is likely shot." So, I guess if that is the case, What is the infrared imagine going to do other than likely stir up more claims of "waterlogged" Whalers. If the infrared imagining can show areas of delamination I could see that as being something of value if you find an area that does not pass the knock test.
Jessielove	posted 04-09-2012 10:30 PM ET (US) Maybe I am missing the point here, but if you or I could see the profile and extent of water soaked foam clearly on a whaler hull, how could that not be a helpful factor in making a decision about a boat as part of a pre-purchase survey? Granted, if you don't care if the boat is waterlogged or relatively dry, then it would not be helpful, but I think all things being equal many if not most or all of us would choose a comparatively dry hull over a wet hull. I can also see the value of such imaging to help someone who wished to attempt to dry out a wet hull or replace some wet or damp foam. I can also envision hull penetrations being quickly scanned to help identify the source of water intrusion. It seems like there could be a many useful aspects to this form of imaging. You would not have to remove a transducer necessarily to determine if the screw holes are leaking. Again, I am thinking of this from the viewpoint of a surveyor who won't or can't do a more destructive form of evaluation, not from an owner's viewpoint who is free to do as he wishes to the hull.