To the Editor, The Report.
Dear Sir,
It is commonplace that most marine surveyors who suffer being taken to Court are usually there because of simple errors in their reporting skills. Over the years I have made a collection of other surveyor’s reports and they are often very instructive both as to what to put into a report and what to leave out or not to say. Perhaps the most common of the errors that I have seen over the years is the use of so-called reported dimensions not measured ones. I should point out that the marine surveyor’s report is a legal document and therefore requires a content that he has measured, weighed, tested, or examined, whatever, not what he has been told by a third party who may, or may not, have given him valid and correct information. Reported dimensions are hearsay and, as such, are not admissible in Court except under very special circumstances. The precise definitions of the principal dimensions of a boat up to 24 metres length are given in the publicly available document ISO8666 a copy of which should be in every small craft marine surveyor’s library. I would like to see Karen Brain’s comments on this paragraph.
On another, related point, such reported dimensions are usually only the length, breadth and draught, the definitions of which are rarely given. There are no less than six definitions of length of which I am aware, the ISO definition of Hull Length being only one of them.
Similarly, with the breadth, there are three recognised definitions, again, the ISO definition being one of them. If a boat got stuck in a lock, a marine surveyor would have difficulty in defending himself in Court by stating that he had relied on a broker’s reported dimension for the overall breadth.
Why do so many people ignore the hull depth and freeboard? Here again, there are two definitions of the hull depth. The depth dimension controls the vessel’s longitudinal and transverse strength, the height of her centre of gravity, her stability and metacentric height, the area under the GZ curve, the maximum GZ value and it angle, the deck edge angle and angle of vanishing stability, the freeboard, the amount of reserve buoyancy and the minimum angle and height of downflooding. Measurement of the freeboard on both sides of the vessel will indicate whether or not she sits upright or has a permanent list. None of which are items to be ignored.
Similarly, with the draught which should be measured from the waterline to the underside of keel with an extra measurement taken to any skeg or Dutch keel. In the case of vessels which may have to navigate under bridges or through tunnels, I would consider it good practice to also measure and report the air draught. If the water draught is measured at the vessel’s midlength it is possible to check as to whether her sides are parallel and whether or not she is wracked or has suffered other deformations such as permanent set from hogging or sagging. That is particularly so with those marine surveyors who survey narrowboats and similar canal craft. I think it also good practice to measure and report the length of any skeg underneath the bottom plating from the centreline of the rudder stock to the forward end of the skeg which would be a great help to anyone who has to lift the boat from the water and sit her down on keel blocks.
I think it also good practice to measure and report the cabin height from the top of the cabin sole to the underside of the deckhead lining.
Yours faithfully,
8 | The Report • June 2021 • Issue 96
Letter to the Editor
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