Bertram Yachts boats changing its lay-up

bertram fiberglass offshore race boat

Winning Bertram race boat from the past


After years of success on the race courses of the world and having won numerous

fishing tournaments, Bertram is going from a traditional lay-up for its yachts to open molding infusion.

Bertram fish boat convertible fiberglass diesel inboard

new Bertram 64 convertible fiberglass fish boat


Using vacuum-assisted resin infusion for the yacht’s hull and deck as well as the small parts is their way to add top speed to their boats on the water via an all-up weight savings. Initially, their 64 fish boat will go between a knot to a knot and a half faster at WOT with the roughly 10,000 lbs. weight savings in hull number one using this lay-up change

“We were looking to increase strength with a re-engineered composite laminate design,” says Robert Ullberg, Bertram’s VP of product development and engineering. Ullberg and company president Herndon worked with Vectorworks Naval Engineering in nearby Titusville, Fla. to collaborate on infusion-optimized laminate designs. Also used was Composites Consulting Group from Texas a composites design company with the intended core supplier DIAB Group from Sweden. Bertram used a DIAB foam core, either grooved or flat, depending on the location of the core within the boat. Fiber manufacturer Vectorply Corp. in Phenix City, Ala. assisted and supplied the fiber reinforcements for the hull and deck, while Interplastic Corp. – Thermoset Resins Div. of St. Paul, Minn. consulted and supplied the resin.


bertram 64 hull being laid-up

building the hull and stringers for the Bertram 64 fish, the wood comes out as they are just spacers


The RINA and the standard “Small Craft – Hull Construction and Scantlings It is said that the RINA assumed a top speed of 46 mph at maximum boat weight in a sea state with a13-ft wave height. Wow!

One of RINA’s Rules for Classification of Pleasure Yachts were respected as well as the ISO 12215 the more interesting issues was a through look at the stress of each layer or ply of the lay-up. This issue has a great effect on the durability and smooth finish of the gelcoat over the life of the vessel.

The placement of the stringers along the hull’s length was driven by the locations of engines and tanks as well as the gyrostabilizers. The four longitudinal stringers contain a high-density foam core, covered with special fiberglass fabric. The longitudinal stringers were infused along with the hull laminate in this Bertram. This was done that the stringers would bond completely to the hull. It did require separate vacuum ports along the stringer top points for best wet out.

With the foam core and the two fiberglass skins, the hull laminate thicknesses range from 3/8-inch to 2-inches. DIAB H100 1-inch thick closed-cell foam core material was used mostly for the hull bottom, and H80 1.5-inch foam core for the hull sides. However, the deck and the flying bridge are mostly 1.25-inch cored sandwich construction. Note, the entire hull was vacuum bagged and sealed.


fiberglass Bertram v drive race boat

Note, the shaft drive on this early Bertram race boat

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