Trailers and Duroboats

 

Know and follow all legal and safety requirements of the state(s) in which you will operate your boat and trailer. Know and follow all recommendations and limitations set by the trailer's manufacturer. Know and follow the recommendations and limitations of the maker of you tow vehicle. Your trailer must be rated to handle the weight of your boat motor and gear, which in turn should not exceed the limits stated on the boat.

It is critical that a boat be properly supported on the trailer. A boat traveling on a trailer will often experience stresses greater than it will see when underway in the water. Keels and transoms are the points on any boat most likely to be damaged by trailers. This is because there is significant weight (typically a motor) on the transom and sometimes concentrated pressure points on keel rollers.

When a trailer hits bumps or rises in the road motor weight is put in vertical motion. It can come down with great force. This force tries to rip a transom from a boat or bend the transom away from the bottom of the hull.

How do we prevent damage? Transoms can be made bigger, heavier and stronger, and they sometimes are, but as transoms get bigger and heavier boats become back end weighted, more costly and heavier over all. Motors used on heavier boats must be themselves heavier and more costly. Boat designers strive for a good balance between strength, weight and cost when deciding how a boat will be built.

With proper set up a trailer should support the boat motor and gear for which it is designed in normal conditions. Normal conditions do not include travel on rough roads at speeds that will induce damage. Drivers must always be alert for potholes.

The key to mounting the boat, so as to limit damage is to, support the boat evenly, distribute the weight, not overload load the boat with gear and keep the boat firmly fastened to the trailer so the trailer suspension will dampen shocks and the boat will not move independently of the trailer.  Correct positioning on the bunks or rollers is very important. Trailer tongue weight must be at an appropriate level. The overall center of gravity should ideally be over or just forward of the trailer wheels, this may not be achievable with an aluminum boat and outboard but having the motor weight closer to the wheels is better.

Note: Most trailers can be adjusted to comply with the requirements that follow.

This is how a Duroboat should be mounted on a bunk trailer

Bunk trailers typically have long boards (called bunks) that form a cradle for the boat. They usually are carpeted to prevent marring of the boat finish and to provide a surface for the boat to slide on when launching or retrieving. Some bunks may use a surface different than carpet. Whatever surface the bunks must be undamaged to prevent damage to a boat.

Bunks must be mounted flat side to the boat not as rails. They should be angled to lay flat against the hull. The maximum amount of surface in contact with the hull is what is necessary. The widest bunks that will fit consistently between the strakes are best. The strakes are the long pressed aluminum ridges that run from front to back along the bottom of a Duroboat.

When the boat is on the trailer the strakes must not be resting on the bunks. Bunks must be between the strakes. Strakes on the bunk concentrate weight on too narrow a surface.

The bunks should extend beyond the rear of the boat. Two inches is desirable. Under no circumstances should bunks terminate short of the transom. If they do they will create an edge that will act as a pressure point on the hull. The bouncing motor and transom will work on this point and cracks may develop in a hull.

Keel rollers are to help the boat into position on the trailer. When at rest, the hull must be supported by the bunks. Very little weight, possibly no weight should be on keel rollers.

Check the final alignment of the boat every time you put the boat back on the trailer. Secure the boat to the trailer with appropriate tie downs. Secure the trailer to the vehicle as prescribed by the trailer manufacturer or applicable law. Make sure lights and brakes if applicable are functioning properly.

Use transom savers with motors near the maximum horsepower or weight capacity of the boat. This may be necessary for back end weighted four stroke motors.

This is how a Duroboat should be mounted on a roller trailer

Roller trailers have groups of rollers that allow the boat to roll on and off the trailer. The rollers are also the points at which the boat is supported when it is on the trailer. In general and to the extent practical more and larger rollers will supply more and better support. Rollers usually can be adjusted and will pivot to conform to the shape of the boat hull that is being transported.

Adjust rollers to spread the weight of the hull evenly and over as many hull rollers as possible. Keel rollers are to help the boat into position on the trailer. Very little, possibly no weight should be on keel rollers.

Make sure that when the boat is at rest on the trailer that all rollers set between the strakes of the boat. The strakes are the long pressed aluminum ridges that run from front to back along the bottom of the boat. Strakes must not ride on the rollers.

On a Duroboat it is best to have the rear most rollers away from the transom. It is critical that the rollers not rest in the area just ahead of the transom. It will act as a pressure point against which the weight of the motor on the transom can flex the hull, possibly inducing a crack.

The best place, for the rear most rollers, is somewhere between 8" forward of the transom to just below the stern side of the rear seat.

Check the final alignment of the boat every time you put the boat back on the trailer. You must secure the boat to the trailer with appropriate tie downs. Secure the trailer to the vehicle as prescribed by the trailer manufacturer or applicable law. Make sure lights and brakes if applicable are functioning properly.

Use transom savers with motors near the maximum horsepower or weight capacity of the boat. This may be necessary for back end weighted four stroke motors.