Surveying Wood Hulls
by David H. Pascoe, Marine Surveyor
Now that I have roundly
criticized the Coast Guard for their role in the EL TORO II tragedy,
it's only fair that I should offer some effective solutions on how to
prevent these casualties in the future. I fully recognize that it is
easier to be critical than to solve the problems being criticized. Yet,
in the EL TORO II tragedy, a wooden vessel which sank and killed three
people because of wasted hull fasteners, the NTSB and the Coast Guard
blamed a lack of "adequate guidance" for the CG's failure to locate
these faulty conditions on EL TORO.
Contents
- PART 1:
Materials and Causes of Problems (with 4 pictures) - PART 2: How to Survey A Wood Hull
- PART 3: Appendix
Introduction
This essay proposes to fill the alleged gap by offering a general discussion of how to approach the survey of a wood hulled vessel. In addition, I would recommend a thorough study of WOOD: A Manual for its Use As a Shipbuilding Material, Department of the Navy, 1957, ISBN 0961060204, and Ian Nicholson's Surveying Small Craft, Sheridan House, 1987.
I also recognize that in this day and age when very few wooden boats are being built, and most have gone the way of buggy whips, there's not much opportunity to gain experience in wood vessel survey. Yet the overriding feature of the surveyor's art is just that: experience. And since the Coast Guard is reported to survey over 1400 wood vessels annually, certainly no one has a better opportunity to gain that experience rapidly and amass a large body of comparative data rapidly.
As their own studies and data has shown, the U.S. wooden boat fleet is aging and deteriorating. Because of that, the of accidents like EL TORO are likely to increase unless the CG does not only a better job of surveying them, but also of mandating repairs or condemning them once structural deterioration has reached the point of no return.
Let start with the point that most independent surveyors I know are no longer in the business of performing prepurchase surveys on wooden boats and the reason is simple. Surveyors have learned the hard way that surveying wood boats is very difficult and fraught with risks. As private individuals, marine surveyors cannot fall back on lame excuses such as not having adequate guidance, or not finding any evidence or being inhibited in one way or another at locating serious safety defects. The civil courts charge us with the utmost degree of care in conducting that survey, and we are held accountable when we fail, an accounting that more often than not destroys our careers.
This is not to say that serious structural defects cannot be found with relative ease if one knows what he's looking for. In my 30 years experience with wooden vessels, it's a maxim that structural problems always manifest telltale signs. The difficulty is that the inspector must be expert, and must have a great deal of experience in knowing what to look for in order to find them.
It should be recognized that the following discussion covers only the most basic aspects of wood hull surveying. It would require an entire book or series of books to address the subject in its entirely. (NEXT)
- Introduction
- PART 1: Materials and Causes of Problems
(with 4 pictures)
Materials: Wood - Metals, Corrosion: Electrolysis - Galvanism - Stray Current - Oxygen Starvation, Other Factors: Climate - Hull Stress - Wood and Water - PART 2:
How to Survey A Wood Hull
Opening Up - Planks & Frames - Weepage - Chine Areas - Forefoot - Transom - Keel, Bolts, Keelson, Clamps and Stringers - Inaccessible Areas - Fuel & Water Tanks - The Exterior - The Bottom Survey - Steel Fasteners - Screw Fastened Vessels - Acceptable Degree of Wastage - Summary of Structural Strength - PART 3: Appendix
[A] Hull Planking Types
[B]Recommendations for Safety Equipment and Systems
First posted 5/25/97 at David Pascoe's site www.yachtsurvey.com.
Page design changed for this site.
Professional Marine Surveys
- Hull Design Defects - Part I
- Hull Design Defects - Part II
- Surveying Boats With Molded Integral Grid Systems
- Surveying Wood Hulls
- Avoiding the Blister Blues
- Sinking of EL TORO II
- Storm Damaged Boats
- Insurance Surveys and Reports
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