Jim Cross Certified Marine Surveyors

Hull to Deck attachments

How the deck is mechanically secured to the hull is important for several reasons.

The overall integrity of the structure is dependent upon how secure the hull to deck

attachment is. If a surveyor inspects ten vessels during the next couple of weeks he

will probably find at least six different methods of hull to deck attachment,

and in most cases it will be almost impossible to examine this important

area of the structure thoroughly without removing sheathing, wall coverings, or

other devices used to trim the interior of the vessel.

Typically the hull is molded in one section and most of the interior work is completed

before the deck is installed. The deck is molded in much the same way as the hull

and when completed is lowered on to and securely fastened to the deck flange.

In a good-quality, contemporary, offshore vessel the mating components are epoxy

glued and secured with non ferrous nuts and bolts. This joint is of vital importance

because in a good secure mating of the hull/deck components the structure becomes

a very seaworthy unit with appropriate integrity. The properly designed and secured

deck provides the structural integrity necessary for ocean use.

During one of my trips to Block Island I observed an 80’s vintage 32 Trojan en route

from Block Island to Narragansett Bay with the forward section of the deck raised

about a foot above the hull. I checked this situation upon my return to port and

found that the fore deck had been repaired recently because of soft spots and

some delamination. The hull/deck joint was not glued and only a few self tapping

sheet rock screws kept the deck from lifting. The repair failed, compromising

the integrity of the bow. When the structure was subjected to rough seas for over an

hour the hull/deck joint failed. There are enormous forces applied to the bow section

in rough seas at high vessel speeds.