Surveying Fiberglass Power Boats
by David Pascoe
Deck & Superstructure
9. Deck & Superstructure 209
Hull-to-Deck Joint 209
Methods of Attachment 211
Weak Hull Sides 212
Core Materials 216
Tenders, Pulpits and Davits 223
Excerpt: Chapter 9
The hull-to-deck is one of the more critical, and often one of the weakest, joints involved in the construction of a fiberglass boat.
It is the unifying structure that ties the other three sides of the hull together. Not only does it have to be strong enough to withstand the stresses imposed on it by the dynamics of the hull traveling at speed, but also to withstand the impacts and abuse it receives from hitting up against dock pilings.
For the builder, attaching a deck to a hull is a time-consuming process that provides the motivation to perform the task as quickly and cheaply as possible.
Over the years, walking through boat yards, walking down the rows of boats, I've marveled at the percentage of all boats that have rub rails that are loose and starting to fall off.
I always thought that it was just because the builder did a poor job of installing the rub rails, selecting poor materials and not fastening them right.
Of course anything attached to a fiberglass laminate with screws doesn't have much holding power. Screws set into fiberglass shatter the laminate ? particularly when the pilot holes are not exactly the right size ? and make for a naturally weak joint.
It was not until I actually began my research of observing what happens to a hull when it is underway in a moderate sea that I began to realize that loose guard rails and weak hull/deck joints involved more than just fasteners.
On smaller boats, the deck and rub rail are often installed all in one operation; on larger boats it's usually done in two operations.
Bolting the deck to the hull is much better than screwing it, but then I began to notice that even some bolted deck joints came apart and so I wondered how this could be.
Ultimately it was discovered that panting of the hull sides and bending of the hull longitudinally was usually responsible for the loose guard rails.
But behind the loose guard rails was a larger problem of a damaged hull/deck joint caused by panting hull sides.
This accounts for why so many guard rail repairs fail: fastening a new rail onto a deck joint that is loose and continues to work inevitably results in the newly fastened rail to work loose as well, usually sooner rather than later.
(Additional spaces are added for easy screen reading.)
- 2nd Edition
by David H. Pascoe
Publisher: D. H. Pascoe & Co., Inc.
David Pascoe - Biography
David Pascoe is a second generation marine surveyor in his family who began his surveying career at age 16 as an apprentice in 1965 as the era of wooden boats was drawing to a close.
Certified by the National Association of Marine Surveyors in 1972, he has conducted over 5,000 pre purchase surveys in addition to having conducted hundreds of boating accident investigations, including fires, sinkings, hull failures and machinery failure analysis.
Over forty years of knowledge and experience are brought to bear in following books. David Pascoe is the author of:
- "Mid Size Power Boats" (2003)
- "Buyers’ Guide to Outboard Boats" (2002)
- "Surveying Fiberglass Power Boats" (2001, 2nd Edition - 2005)
- "Marine Investigations" (2004).
In addition to readers in the United States, boaters and boat industry professionals worldwide from over 70 countries have purchased David Pascoe's books, since introduction of his first book in 2001.
In 2012, David Pascoe has retired from marine surveying business at age 65.