Bertram 31 Legend
In 1960, Miami sailor, powerboat racer and yacht broker Dick Bertram entered the 165-mile Miami-Nassau off shore powerboat race with an innovative Ray Hunt design called Moppie. In eight-foot seas and 30-knot winds, Bertram blew the competition away and won the race in record time, two and a half-hours ahead of the next boat to finish. Bertram became convinced Hunt’s prototype represented the design of the future. He made a mold of the hull and in 1961 launched Bertram Yachts with the introduction of the Bertram 31 Sport Fisherman. After over 1,800 hulls, regular production of the Bertram 31 ended with the 1983 model year. (In 1986 / 87, Bertram produced 23 “Silver Anniversary” versions of the 31s, although none have been built since.)
The Bertram 31 was a radical departure from mainstream thinking about what made a powerboat per form well. The most unique feature of the Bertram 31 is what has become known as the deep-vee hull form.
Typically, planing hull powerboats had fairly steep deadrise (the angle of slope from the hull centerline to the chine) in the forward sections that gradually flattened to about a five- to ten degree angle at the transom. Designers felt if the deadrise were further increased in the after sections, a significant increase in horsepower would be needed to raise the boat onto and maintain a plane. Hunt reasoned that by incorporating lifting strakes along the bottom he could provide adequate lift without requiring excessive horsepower and, at the same time, significantly improve performance and ride.
The Bertram 31 and its prototype were designed with a remarkable 23-degree angle of deadrise at the transom with three lifting strakes on each side from the keel to the chine. The concept worked and Hunt’s deep-vee hull , monohulled boats for more than 40 years. The 31 actually measures 30′ 7″ length over all, has a beam of 11′ 2″, a draft of 3′ 1″ and displacement of around 11,000 Ibs. It may sound trite but they just don’t build them like this anymore. In my opinion, the Bertram 31 is one of the most robustly built boats of any size or material. Hulls are constructed using fiberglass cloth, woven roving and fiberglass mat in combination with plastic resin. Lay-up is more than 1/2″ thick on the bottom near the centerline and, even at the sheer, measures in excess of 3/8″. Decks are also a solid laminate of fiberglass and resin and measure 1/4″ thick or greater in most areas. The deck and hull are joined on a narrow outward flange with mechanical fasteners every 4″. There is very little use of core materials. The Bertram 31 is one of only a few production boats I have come across in my career that I can say I have never seen any significant structural failure, even on boats that have endured very tough service. The Bertram 31 is first and foremost a fishing boat. In fact, this is one of the few small boats still competing in bluewater fishing tournaments. All models were equipped with V-berth accommodations, a marine toilet and minimal galley facilities.
The Cruiser and Sport Fisherman models were equipped with a dinette area that converts to a “cozy” double berth. The cockpit, however, is where this boat shines. There is more than a 110square feet of space, which accounts for more than half the space aboard. Most Bertram 31s were powered by two 330-hp Mercury Marine inboard engines. The combination provides a respectable cruising speed of about 26 mph and top speed of around 37 mph. Over the years several models of General Motors, Caterpillar and Cummins diesel engines were offered as options. The diesel engines generally resulted in improved cruising range. The engines are located in near midship in insulated raised boxes, completely removable and allowing excellent access for servicing. Fuel capacity of the original Bertram 31 was 170 gallons.
The Bertram 31 has become legendary for her ability to handle big seas in relative comfort and safety. But another attribute absolutely necessary for a successful fishing boat is maneuverability. The 31 is easily controlled whether in head seas, following seas, fighting a fish or docking at a marina. As testament to the lasting value of the Bertram 31 Sport Fisherman. In fact, a substantially restored and repowered ’60s Bertram could sell for six figures. Some have argued the Bertram 31 is the best powerboat ever built. It surely ranks near the top of my list for this size and class and if there were a Hall of Fame for powerboats this would no doubt be one of the first inductees.