37 Billfish Construction
37 Billfish Construction
Welcome back to the 37 Billfish blog!
As you know, Ocean Yachts is a leader in the innovation of new products in the sport fishing boat industry. Innovation often involves the use of new and improved methods and materials, many of which have been incorporated into the 37 Billfish. We’ve received many inquiries from our customers and the boating community regarding the Billfish, so we thought it would be interesting to share with you one of the many innovations. While the 37 Billfish’s hull lamination is similar to our other models, the lamination and installation of the stringer system is a new and different process. The following explains how our hulls and stringers are manufactured and fused together.
Hull Lay-Up
The 37 Billfish hull lamination is completed using the same process as all of our models. The open hull mold is first waxed and then sprayed with gelcoat. Fiberglass mat is hand laid with blister resistant vinyl ester resin. The hull sides above the water line are cored with a high density foam called divinycell. The bottom from the water line down is laid up completely with solid fiberglass.
Stringer Lay-Up
The stringer system is laid up in a one-piece, female mold in the lamination shop. This is done in a similar manner to the hull lay up. The mold is waxed and sprayed with gelcoat and then laid up with fiberglass mat. The difference from our other models is that the Billfish’s stringers come from a female mold instead of a male mold. When the stringer system is fully cured and the part is “pulled”, the top side of the stringer has a smooth, gel-coated finish. This smooth finish is built in, as opposed to having to grind, fill, and fair.
Stringer Install
After the stringer system is trimmed, the part is dry fit inside the hull. This insures proper tolerances between the stringers and hull. Then the outline of the stringers is traced onto the hull. This ensures the stringers go back in the exact location where they were dry fit, and also serves as a guide for the application of the bonding material.
The dry-fit stringers are lifted out of the hull so the bonding agent (Ocean uses Plexus) can be applied. Plexus is applied along the landing surfaces of all stringers, cross members, and panel stiffeners. Plexus is a methacrylate adhesive that chemically fuses at a molecular level, forming bonds stronger than the substrates themselves. This installation process creates panel stiffness above ABYC standards.
After the Plexus is applied, the stringer system is lowered back into the hull using a weighted fixture that helps press it into place. In addition to ensuring acceptable installation tolerances by dry fitting, inspection holes are located throughout the stringer system at inspection points so that proper bonding is assured visually. Each panel section of the hull has bonding material applied around its perimeter. In the center of certain panels there is an engineered non-contact area. These “purpose gaps” are engineered so that the stringer grid makes contact with the hull around the perimeter of the panel as designed, not in the center of the panel where there is no stringer.
Once the stringers have been installed and the bonding agent has fully cured, the stringers are then foam injected for added strength and sound dampening.
Through-Hull Installation
The hull and stringer system now bonded together as one, moves into the mechanical stage where engines, pumps, through-hulls, etc. are installed. The stringer system on the 37 creates a unique situation when installing through-hulls. Most through-hull fittings need to be installed in the purpose gap panels of the stringer system. To provide the most reliable, leak-free installation it is best to install each through-hull fitting “hull to hull”. To do this we must remove a section of the stringer liner around each through-hull installed in the boat. This guarantees a solid installation.