- Galvanized steel - trailers have galvanized steel skeletons. This type of framing is the most solid way of making boat trailers. They also offer the best protection in the brake lines and the wiring systems (if the steel is enclosed e.g. box section or tubing).
- Aluminium - trailers are made of high quality aluminium alloy so are therefore very light compared to the other option of steel. Aluminium trailers are strong, but they don’t have the durability of a steel trailer. Aluminium however wouldn’t rust as much as steel. You can also galvanise aluminium for added rust protection.
- Steel – trailers have the same structural qualities as the galvanised steel trailers apart from the corrosion
- Alot of manufacturers give the customer a choice of galvanized steel or painted steel trailers. The painted trailers are ideal for freshwater but are vulnerable to rust in saltwater, Galvanized trailers cost more, but it means less maintenance, especially if they will be reversed into saltwater.
TYPES OF CONSTRUCTION METAL
- The best type of steel to use on a boat trailer would be an enclosed type of shape e.g. tube or box section, this is because you can run your light wires etc. inside the steel so it is protected from impact from all sides, weather (sun perishing cables) and salt water if the trailer is built with drainage holes at the lowest points. It is important however that even with an enclosed cable space and drainage holes that the wiresneed to be properly insulated.
- If you decide to build a trailerusing I-beam or C-channel Iwould recommend using steel then spending that littlebit extra to get it galvanised. This is because an aluminium alloy trailer built out of I-beam or C-channel is not strong enough.
TYPES OF TRAILERS
- Single axle - trailers with a single axle are much easier to manoeuvre by tow vehicle or by person, the downside to a single axle boat trailer is that at high speed there is more chance of it fish tailing from behind the car than a tandem axle trailer, it is also more important for a boat to be in the right position over the apex on a single axle trailer compared to a double because there is more support on 4 wheels rather than 2.
- Roll-on trailers, also known as Roller style trailers, uses rubber and or polyurethane rollers for ease of launching and loading the boat without submersing the trailer very far in the water.
- Glidepath trailers, also known as a Float-on style trailers allow the boat to float onto the trailer. This is made possible because the trailer gets driven so it as submerged to about 3/4 of the trailer is under water.
- Pros - The roller trailer - you don’t have to drive the boat so far into the water to get the boat onto the trailer, and the rollers them selves make the winches job much easier. The guidepath trailer means that there is hardly any effort to get the boat onto the trailer because the water has all the weight.
- Cons – roller - saltwater eats away at the bearings on the rollers which causes the rollers to seize and the winch therefore is put under more strain because it is having to drag the boat over the rollers.
- Guidepath - because the trailer is being almost fully submerged in the salt water there is more chance it would rust.
- When choosing the trailer you have to take into account where you will be launching the boat e.g. is there a drop off at the end of the boat ramp, if so the roller trailer is the better choice because you don't have to drive it into the water so far.
OVERALL DIMENSIONS & RULES
- If you own a boat you can tow a trailer that can be 2.5m wide, up to 4.25m high when the boat is sitting on the trailer, and 11.5m long, assuming that the car plus the boat doesn't exceed 20m which is the limit.
- When you load your trailer the I deal position is to have the weight is so about 10% of the weight is taken on the tow ball and the rest supported and distributed over the single/tandem axles of the trailer. If there is to much weight on the tow ball the trailer coupling will not be parallel to the ground therefore the car will be hard to steer (and good luck pulling your boat up a steep launch ramp if the car is front wheel drive). If the load is to far to the back of the trailer it will have the tendency to fish tail around at certain speeds.
- Another thing to consider is what gear you have in the boat, “is it heavy” if so where is the weight adding to the load.
- The tongue of the trailer is also very important – the A-frame design has the coupling of the trailer where the apex of the frame meets.
- The draw bar style has a strut running through the apex of the A - frame which extends out futher and is attached to the towbar by a coupling.
SUSPENSION TYPES
Leaf springs single axle- Advantages : This is the most common type of suspension and probably the most used for boat trailers. They minimize stress on the frame because it distributes the load over 4 equal points on the frame. They are easy to set-up so the axle position is correct according to the main frame of the trailer. They are attached with through bolts for simple constraints of the system, and the back shackle is a simple, dynamically stable method of taking up spring deflection.
- Disadvantages : include size, weight, and package constraints (they can take a lot of room under the trailer and limit how low the bed can be made.
- Advantages : Mostly the same as above, but for multiple axles, these springs distribute a simple load fairly well to 8 points on the frame instead of 4. These can be made to load share quite well with a rocker link (usually included).
- Disadvantages : Like above on the single axle, these take a lot of space and make limitations on trailer bed height. Different variations exist, but typically for load sharing the rear axle is not as well constrained as the front, so these tend to be somewhat less stable than the simple single axle.
Overall leaf spring suspensinion is more practicle all round and better for boat trailers because the boat wil be on rollers or guidepaths the height of the bed is not a big factor.
WEIGHT LIMITS FOR BOAT TRAILERS
If the load on the trailer adds up tomore than 2000 kgs it has to have a braking system, this mostly applys to single axle trailers because dual axle trailers usually have a breaking system anyway.
| Trailer Weight Estimates | ||||
|---|---|---|---|---|
This chart relates to single axle trailers only | ||||
| Trailer Capacity | No. Axles | Trailer Length | Trailer Width | Weight |
| 1000 lbs. | 1 | 15'4" | 62" | 295 lbs. |
| 1500 lbs. | 1 | 15'4" | 62" | 305 lbs. |
| 2000 lbs. | 1 | 17'2" | 88" | 492 lbs. |
| 2450 lbs. | 1 | 18'2" | 96" | 522 lbs. |
| 2999 lbs. | 1 | 18'2" | 96" | 625 lbs. |
| 3500 lbs. | 1 | 19'8" | 96" | 677 lbs. |
| 5000 lbs. | 1 | 20'8" | 96" | 933 lbs. |
| 7000 lbs. | 1 | 27'9" | 96" | 1512 lbs. |
BRAKES
Most trailer braking systems are either cable or hydrolicly opperated.
HYDROLIC - Also know as serge braking system, this in my oppinion is the most effective and economical form of trailer braking because it significantly reduces the wear and tear on the axles and wheels, this is because the brakes are being used even whilst driving (only when slowing down).
hav 2 carry on, on a new post dont know y!!
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