Hull to Deck attachments by Jim Cross
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 you inspect 10 vessels during the next week 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 80ís 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.