Port Credit
Marine Surveys
& Yacht Delivery

Society of Accredited Marine Surveyors

American Boat & Yacht Council


Our business slows (actually drops dead :) ) down over the winter months and I get a little stir crazy because I'm the type that needs to keep busy. So while we will survey some frozen boats (maybe) at very close to 0°C (maybe, it depends) but not any colder, It is important that you understand the limitations of what I can tell you about moisture content and core condition of hulls, decks and stringers at lower temperatures (not much) it is a risky proposition. All boats should be well above 0C for several days prior to survey and boats with cored hulls should be above freezing even longer depending on conditions. I once surveyed a boat with saturated core that was frozen solid after a week of well above freezing temperatures. This boat was stored among trees and had no direct sunlight at all. The primary methods of determining core condition and moisture content are ......
Moisture Meters do not measure moisture, they measure capacitance (pretty much like conductivity). When moisture in the structure is frozen, it crystallizes and all that air between the ice crystals reduces conductivity so the meter gives false low readings.

Percussive Sounding (Whacking with a hammer) is the other and sometimes more reliable method of finding wet core but when frozen, the core often sounds like dry, solid core unless there is some delamination, core separation or a large void.

Thermography We also have a Flir infrared camera and it won't work either as it needs temperature differentials to create a picture. If the whole boat is at one temp ... no go unless you want to pay by the hour while we set up heat lamps.We only use this method in rare cases (even in summer) due to the complexity and time required to do it right.

While we have occasionally (rarely - it depends) surveyed frozen boats, you must realize that we cannot positively tell you the condition of any cored structure whether it be balsa or foam core decks & hulls or stringers or the very common weak spot of all i/o boats - the transom. It is rare to find an older boat without some degree of moisture in the core or between the laminate and the core. Please also note that on rare occasions we have seen boats just a couple of years old with large areas of rotten core and don't forget that the surveyor might not be as reliable when his fingers are frozen.

Rotten deck core is an expensive problem to fix and please also remember that we can only inspect what I can get to. Canvas or shrink wrap covers will certainly hinder examination to some degree.

If you are considering a vessel with a cored bottom and want to have it surveyed in a frozen state please consider hiring someone else as we don't like working for crazy people
Aside from the structural issues that cannot be determined .... the fresh water system has been winterized and cannot be tested, Batteries have been disconnected and DC systems may not be tested. Engine coolant may have been changed and there is not much one can tell by looking at fresh coolant, The oil has most likely been changed so an oil analysis is a waste of time. If the mast is up, it is almost impossible to examine the rig properly, if the boat is shrink wrapped access may be too limited depending on how the wrap is fitted. In fact there are just to many limitations to perform a proper survey.