The affair marked the 18th in a series of yearly boating parties that Avtex has sponspored. It started with buffet luncheon at Les Pyrenees and ended several hours later at the New York Coliseum where everybody got an advance look at the new power and sail boats on exhbiit at the 76th National Boat Show there. The show opened to the public this week.
Although virtually all major fiber producers have latched onto sporting events — tennis, golf, football, jogging, bike riding, mountain climbing, even dog sled mushing — Avtex is the only producer to tie in with the boat show.
“We wanted to sponsor something entirely different than anyone else,” commented James Crutchfield, executive, vice president and head of marketing. “Since a number of our most important mill customers own and run boats, we thought a tie-in with the boat show would be a good idea. Now it’s become a tradition — a sort of forerunner of spring in the midst of winter.”
John Kelly, former advertising manager of Avtex, now president of Kelhan, Ltd., a promotion agency, noted that boating today is the top recreational sport in the United States with some 67 million persons participating in boating activities. And they spend more than $13 billion at retail on boats and accessories annually — including, of course, boating apparel of nylon, polyester and rayon.
Kelly noted there are more than 13,900,000 registered boats in the U.S. with nine million power boats, 1,500,000 sail boats and the remainder small nonpower crafts including canoes, row boats and the like.
For those who find statistics interesting, Kelly noted Michigan leads all states in number of registered boats, with California, Texas, Florida and Minnesota close behind.
Further, he noted, many top textile executives are involved in recreational boating, including Donald McCullough (Collins & Ailkman), Don Reed (Alice Mills), Myron Silverstein (Cone Mills), Arthur Weiner (Burlington), James Raleigh (Clinton Mills Marketing), Tom O’Gorman (Greenwood) and Norman Weisbecker (Guilford Industries), to name only a few.
with a crew like that it’s no wonder the Avtex boat party, sailing into its 18th year, is still going strong.
What better way is there to give customers a welcome respite from the could wintry blasts of January than by giving them a warm look at those sleek-looking fast-moving Sea Oxes, Glastrons, Mako’s Boston Whalers, Grady White’s, Hatterases, Chris-Crafts, Bertrams, Uniflites and Egg Harbors — and all the stuff that goes with them.
For boat hulls requiring more strength than provided by a chopped-glass-fiber-strand laminate, layers of fabric can be used as reinforcements. These reinforcement layers, however, must be laid up by hand. As a result, hand laid-up fabrics and their labor costs bump up the boat’s final price.
For the hand lay-up method, fabric must be cut to fit the mold, then roughly one-third of the resin to be used is sprayed onto the mold. The fabric is then laid into the mold and the remainder of the resin sprayed onto it. Boat makers work the resin into the fabric to ensure full saturation of the reinforcements. Finally, workers remove excess resin from the laminate to eliminate excess weight from the hull.
Advantages of the hand lay-up process lie in the strength of the finished hull. The long, continuous composite glass fibers acting as the primary reinforcement accomplish two goals. They significantly increase the glass-to-resin ratio compared to the chopped strand method, and they give the hull a more uniform laminate thickness than the spray gun method.
To put it into perspective, the typical glass-to-resin ratio of a hull made exclusively of chopped glass fibers might be 25 to 30%. The typical glass-to-resin ratio of a hull made of fabrics, however, is in the 35 to 45% range, and under certain circumstances, yields ratios as high as 60%. Manufacturers have found that resin reduction not only increases laminate strength, it also improves boat performance by minimizing the weight of the craft.
Combining these two processes draws on the advantages of both. A spray gun puts down a skin coat, or outer layer of the hull, and once that coat has cured, a layer of fabric is laid down by hand. After rolling and curing the fabric layer, another layer of chop is sprayed on to provide a bonding surface for the next layer of fabric. These steps are repeated until the desired thickness is reached.
An alternative construction method, vacuum-bag molding, makes use of atmospheric pressure. After putting down reinforcements, workers stretch a plastic film over the mold. A vacuum is created inside the film and resin is injected. Atmospheric pressure squeezes the resin into the fabrics. This technique saturates the reinforcements more efficiently than those in which workers use laminating rollers and squeegees. However, this molding technique is one of the most expensive.
All these methods use either polyester or epoxy thermosetting resins. That means once they harden, they cannot be softened by heat. Polyester resins are the most commonly used because of their low cost and chemical resistance. They are also the simplest and most versatile to use in production. Epoxy resins have greater bonding strength and abrasion resistance, but are more costly.
Fabrics vs. woven rovings
Since composite glass fibers became a dominant material in the construction of marine craft, a major change occurred in the hull materials. When fiberglass was first used to make boat hulls, practically all of the reinforcing materials used were either roving, chopped strand mat, or woven roving products. A problem with woven roving fibers is their tendency to shear each other under stress because they run over and under each other.
In the mid-1980s, the Knytex Co. (now a joint venture between Owens-Corning Fiberglas Corp. and Hexcel Corp.) introduced knitted fabrics to the marine industry. Knitted fabrics are nonwoven, unidirectional fabrics made of long, continuous filament glass fibers. They offer strength and performance benefits not found in any other types of composite glass reinforcements.
Today, more than half of all laminates in marine applications use knitted fabrics. These fabrics let boat manufacturers build stronger, lighter hulls. And when repairs are needed, knitted fabrics can be cut into the necessary shapes to repair specific parts of the hull.
A development in knitted fabrics, the use of unidirectional, bidirectional and triaxial versions, has been called the biggest breakthrough in glass fiber reinforcing materials for the boating industry. These new knitted fabrics let builders customize hulls, putting reinforcements exactly where they’re needed. Some of the newer fabrics consist of two or three layers of unidirectional rovings that are stitched to chopped strand mat.
In the early days of composite glass-fiber reinforcements, if a boat builder wanted extra strength in one particular area, layers of woven roving and mat were added throughout the hull. But this increases the weight of the craft. Knitted fabrics and new resins that compliment the newer fabrics, now let builders strengthen only the most critical areas, thus keeping the weight of the boat down and maximizing speed. Moreover, because of these improvements, today’s boat builders can accurately plan their glass-to-resin ratio before starting construction. These enhancements in quality control have elevated product strength and performance.
There are a host of reasons for the transition from wood and metal to fiberglass for pleasure boat hulls. Fiberglass hulls are lighter, stronger and more durable than traditional wooden or metal hulls. For example, they have the same strength of steel or wooden hulls with only half the weight. Furthermore, fiberglass hulls do not corrode, rot, or deteriorate as fast as traditional materials when exposed to salt air or water. Fuels or pollutants often found in rivers and harbors don’t affect them either. Fiberglass is also a relatively low-maintenance boat-building material that is easy to repair. Rising material and labor costs have made fiberglass the economical choice as well.
In addition, there are a couple of reasons for this shift to fiberglass that have their origins in the automotive industry. In the past, many boats were powered by car or truck engines. As Americans shifted to smaller vehicles, due in large part to fuel-efficiency concerns, the days of relatively inexpensive V8 engines ended. The powerboat industry was faced with the challenge of making newer boats that could ply the waves as fast as their predecessors but with smaller engines. Weight became an important factor in boat performance and design, making fiberglass an attractive option.
Another result of Detroit’s shift to smaller vehicles, one that also favored lightweight fiberglass, was that newer cars and trucks could not tow the heavier, older boats. Companies building trailerable boats turned to fiberglass to help them build pleasure boats that weighed less but provided the same variety in size and accommodations the boating public had come to expect.