"Corrosion isn’t a major factor if the boat is used only in fresh water, but if your trailer spends a lot of time in or near the ocean, then you want a metal that resists corrosion,” said Greg Weekes, a boating enthusiast and owner of Eastern Metal Supply, a metal distributor in Lake Worth, Florida.

An aluminum extrusion, with its non-corrosive properties, would be ideal for boat trailers, if someone could develop an extrusion that was pliable enough to bend while manufacturing the trailer, while being strong enough to support the boat, but wasn’t so rigid that it cracked from the vibration and bouncing a boat trailer receives. The experts at Hydro Aluminum's Belton, South Corolina, plant solved the problem.

“People from Belton went to our customers, watched and learned what our customers wanted. Then they went back and came up with a solution. They started with a hard 6061T-6 alloy and developed a special heat treating process for the extrusion,” said Weekes.

The special Hydro extrusion was initially used for manufacturing trailer beams. To make a trailer, two beams are joined in a “V” shape at the front of the trailer then bent a short distance back from the “V” so the beams run straight and parallel toward the rear of the trailer. The trailer is strengthened by bolting cross members between the beams. The beams and cross members provide the structural support when the boat is on the trailer.

The Hydro aluminum extrusion beam is so successful, Florida trailer manufacturers have virtually stopped using steel for beams on trailers that will be used in salt water. Manufacturers are also using the Hydro extrusion for the cross members, which had been made from galvanized steel.

To meet the needs of its trailer manufacturer customers, Eastern Metal stocks aluminum I-beams in heights of 4" to 8", in 1/2" increments, and in lengths up to 45 feet.

“Trailer manufacturers never know what length or weight boat their dealers will sell next, so they don’t know what size trailer they will have to make. They can’t afford to carry an inventory of all the different beams, so they rely on us to stock and supply the beams they need,” said Weekes.

Aluminum has worked so well for the beams and cross members, the next Hydro project is an extruded aluminum bunk fitted with an extruded vinyl-coated insert. The bunk supports the boat when it is on the trailer and the insert is the part that is directly in contact with the boat.

“Bunks have always been made of wood, usually with a piece of carpet or other fabric attached to the surface to prevent the boat from being scratched. But water eventually rots wood and the carpet pad wears out and has to be replaced. The aluminum bunk won’t rot. The vinyl insert not only lasts longer than carpet, but also does a better job of preventing scratching,” said Weekes.

Hydro and Eastern Metal are working together to develop a bunk with an innovative, flexible design.

“On most boats, the hull is flat or pitched at an angle of either 19 or 24 degrees,” explained Weekes. “With wood bunks, the trailer manufacturers have to stock different shaped bunks for the different hulls. The aluminum bunk will be adjustable so one design will satisfy the requirements of most trailer manufacturers.”

Someday, an all aluminum trailer might be possible.

“Steel must still be used for the tongue and axles, but we’re working on changing that now,” said Weekes.