Essentials
for a great boat trailer
Easy loading
Guide the boat in to position
Keep boat in position as the boat & trailer are pulled up the ramp
Strong enough for the load including the
tongue
Axles & tires,
brakes
bunks/rollers
winch
winch post,
hitch & chains
Fit the boat
bunks/rollers at correct height
keel properly supported to take most of the weight
axles properly located for proper tongue load
Easy
loading
When loading a lightweight sailing dinghy, loading is
usually no problem because adjusting the position is easy even after you have
the trailer and boat in the parking lot.
With a heavy boat it becomes very important to get it right even before
you start to pull the boat out of the water.
I have used both bunks and rollers for larger boats. Bunks work alright for a lighter cruising
boat but when the boat gets to be as much as a Morgan 24 ( 5000 lbs ), rollers work a lot better. Using the winch to get the boat initially
as far forward as possible is a lot easier when the boat is allowed to roll
rather than be dragged on bunks. Using
guide posts and a keel guide to keep the boat centered on the trailer is very
important in keeping the boat in position while the trailer is being pulled
out. Without the keel guide the boat
could be as much as 6 inches off center even with the rollers guiding the boat
on the trailer, and would be putting a lot of stress on the rollers and roller
supports. The white guide posts help
the helmsman keep the boat on track as the boat is eased up to the trailer at
the ramp, since the back of the trailer is so far under water and does not do
much to help to center the boat on the trailer. The higher you can make the keel guide the better it is able to
keep the boat in position.
Strong
enough for the load
The axles and tires have a rated capacity. For the Morgan 24 the axles should be at least 3500 lb capacity and of course you will need two of them. Everyone has a favorite tire type and brand but I use the highest capacity I could using standard boat tires and rims. My tires 225/75R15 and are rated at 2560 each and the rims are heavy to match that. I use radials because I think they keep a larger footprint on the road at cruising speed and the larger footprint means less a trailer can sway. There are many sources for tires but I found them using the WEB. See the links at the end of the article for some trailer part sources. My springs are rated at 3000 lbs for each wheel. I try to have all the equipment rated at far more weight than I have just to give me lots of safety factor. When I got the boat and trailer, I realized I would have to do some work on the trailer to make it work for me.
The first thing I did was
to add a tongue extension. My
extension is the slide inside type with two 1/2 inch pins to hold it from
sliding while towing. I have a 3X4
outer square tubing and a 2 1/2X3 1/2 inch square inner tube. It slides as long as there is not too much
tension on it and it has not rusted too much.
Having the pieces galvanized would help a lot. My extension inside tube is about 14 ft long and allows me to
extend the tongue about 9 ft. I use it
most of the time I launch but have found some ramps that are steep enough that
I do not have to use it.
The second most important improvement I made was to add electric brakes to all the trailer wheels. With the trailer loaded, it weighs about 6500lbs and 4 wheel braking on the trailer is a must. Yes, I use electric with no problem, even with the electric coils of the brakes going in the water. The electric coils are sealed and do not allow water intrusion. With the electric brakes, I have a controller in the tow vehicle that lets me use the brake light switch to trigger the electric brakes on the trailer. When I am backing up on a ramp or while parking in the yard, I can turn off the controller and do not have to worry about having the brakes working against me while I am trying to back down the ramp.
The winch post was bent when I got the boat and I decided that it was bent probably because it was to weak for the load the Morgan put on it. I added extra braces and now it is quite sturdy. It should be sturdy enough to stop the boat when you have to apply the brakes hard. My winch post has passed the test already. I use a nylon strap for this and am happy with it. The cable sometimes gets little burrs on them and can dig into your hand just when you least want it. The straps are easy to replace when they get frayed or weak. There was only an old crusty plank for support for the keel on my trailer, so I replaced it and then added side frames to help guide the keel when I was pulling out. The keel now just drops dead center right in place as I pull out. This is real important when the wind is blowing sideways across the ramp.
One last thing that gets neglected on trailers is the safety chains. The kind one would use to keep the dog in the back yard will not be strong enough. I use chains made with 5/16 links. If the trailer comes off the hitch, you do not want the trailer to get away from the back of the tow vehicle. Good safety chain is a must to ensure you will not have your boat and trailer trying to cross the median into oncoming traffic.
Fit
the boat
With the rollers at the right height, most of the weight will be on the keel. If too much is being supported by the rollers, the hull will start to sink in until the keel is no longer supported by the rollers. The rollers should be there to keep the boat up straight, not to support the 1900lb keel. With the boat properly positioned over the two axles, the weight on the tongue should be around 600 lbs. A rule of thumb for that is, 10% of the boat and trailer weight should be on the tongue. This tongue weight keeps the tow vehicle from swaying while at highway speeds. Of course the size of the tow vehicle will determine if more or less tongue weight is needed.
Links
for Trailer Parts and Tires &
Wheels
http://www.etrailerpart.com/15wheel.htm
See the dimensions for my trailer on a separate web page.