The solution to these annoyances is a plastic trailer glide that has a lower coefficient of friction than carpet or wood. The plastic also provides a barrier to the wet carpet. But not all plastic glides are the same.

Before you order the plastic trailer glide solution there are a few things you should consider.

The hull needs to be supported properly. If you use smaller pads, you should space them so that there is a minimal space between, and they should be in a position so that the ribs and spine reinforcing the hull are supported. Do not position bunk pad or rollers on unsupported areas between the ribs.

Also, examine the roller, pad or Bunk Glide. How much surface area actually comes in contact with the hull for support? A typical 21-foot boat is 3500 pounds and needs to be supported in a way that does not leave marks, dents or dimples. Rollers may have as many as 20 pressure points of 39 PSI (pounds per square inch) each having an area of 4 1/2 square inches. Full glides adding up to 3” x 10 feet will have a pressure of only 4 ¾ PSI. Pads 3” x 10” may be as low as 12 or as high as 20 PSI if they have cost saving ribs in contact with the hull.

Another item to consider is how the plastic slide is formed; they can be solid material, extruded or injection molded. A solid slide won’t crush under the weight of the hull and puts a consistent pressure over the surface of the bunk. The extruded slide increases the pressure with less area of contact and the injection mold one has hollow construction with thin walls which if crushed will expose a sharp honeycomb sub-structure; these are frequently only recommended for a craft up to 1500 pounds. Also, the plastic itself is a concern. HDPE with UV inhibitors weathers well and doesn’t crack or decompose. PVC may crack.

All plastic glides will reduce the friction and make loading and launching you boat or personal watercraft much easier. However, you need to be certain that when the craft leaves the trailer in will arrive safely in the water. You need to always keep the bow hooked. Also, you need to be able to control the launch momentum with the proper winch rated for your craft’s weight.

Frequently an owner is concerned with what may happen to the hull finish. Nothing will keep bottom paint from ultimately being worn away; it is the softest material between the epoxy gel coat and the carpet or plastic trailer glide that it rests on and will be sacrificed. However, the plastic will protect the hull from the corrosive effects of the chemicals in pressure treated bunk that will wick through the carpet. The wet carpet will accelerate the osmotic intrusion of water through the layers of fiberglass as the boat sits for extended periods resulting in gel coat blisters. And it causes corrosion pitting on an aluminum boat or pontoon. HDPE glides have a Shore D Durometer hardness of 64 to 68 and a hull Gel Coat Epoxy is normally 83 to 90. If the glides are clean a factory installed gel coat should not get scratched; the only way the scratching can occur is when road dirt or sand is collected between the hull and glide.

When mounting the glide to the wooden bunk you should use screws that will be seated safely away from the hull in a recessed pocket. A stainless-steel truss head or pan head screw will firmly engage the slide. Flat head screws have a wedging effect; frequently work their way out or through the pad and are difficult to get tight. A slotted recessed pocket is preferred to offer an answer to minor thermo contractions and expansion of the material. A 6-foot trailer glide will expand or contract approximately 1/8 inch over a 25-degree change in temperature. It can be even more extreme for UV absorbing black slides; for this reason, some suppliers only offer white glides.