Trailers are usually an afterthought, something you consider after buying – or at least finding – the 505 you want. Many of us have “made do” for years with whatever we could find or acquire cheaply, or have simply roof racked the boat, as it quite light (and this saves you $$ at toll booths!). The truth is that 505 racing is a easier if you have a good trailer, and much easier if you have a working combi trailer system. Here are some thoughts on 505 trailers, based on my 21 years in the class.

A hitch, two tires, and if we are really ambitious, a license plate, some lights, and a trailer chain. That’s all you need, right? Well, that might work for awhile, but your life is going to be much easier if you get a good trailer.

Trailer Requirements

Supporting the Boat

The most important aspect of a trailer is how it supports the boat. Modern fully cored 505 hulls are very stiff and strong, but they may not handle point loads all that well. A poorly supported boat can be badly damaged on a trailer. The best way to support the hull is to have it rest on gunwale supports, and on a center support underneath the centerboard trunk. You want a large enough support area that the load is distributed. Be wary of using carpet on the supports, as it can hold water next to the gelcoat, and can cause gelcoat blistering. Supporting a 505 using pads that support the hull on either side of the centerboard trunk (as you might for many other one design classes), may result in dents in your hull – I know, I have done it! In general pads should be as large as practical, and should be padded with rubber or closed cell foam.

There are other good ways of supporting the boat. A system made by Gaugele in Switzerland relies on multiple large straps stretched from side to side on a frame. This also distributes the load, and cushions your boat from jolts. It is also easy to pull it out of the water because you do not need to align the boat precisely, you just put the boat on the slip and once you are out of the water you can adjust the position of the boat easily.

Another method for making supports is to turn your boat upside down and use it as a mold for making fiber glass bunks. Cover the hull with plastic. Cover that with a couple of layers of corrugated box board taped to the plastic, make the cardboard as thick as the carpet you plan to use to pad the bunk, Put another layer or two of plastic over the cardboard, Then drape layers of glass, wood etc. to make a conformal bunk(s). Use a carpet that does not hold water, as it may cause gel-coat blistering as discussed above.

Consider how the boat will be placed on an off the trailer before you make the bunks. If the bunk is placed aft of the maximum beam point, you will not be able to slide the boat onto the trailer from astern, or slide it off the back of the trailer. The bunk may also put a point load (actually a line load) on the hull if the boat is tilted foreward or aft on the bunk while being put on or taken off.

Getting On and Off the Trailer

In many sailing locations, 505s launch off beaches. Your life will be forever easier if you have a dolly [For some reason we call it a dolly in the US while everyone else calls it a trolley] that you can wheel the boat down a ramp or down a beach on, and right into the water. Having to lift a boat off a trailer and carry it to the water is going to get very old after you have done it awhile. If, on the other hand, you normally launch using a crane, you can live without a dolly – at least until you go to an event requiring beach launching. Never-the-less simply moving the boat from a parking spot to the crane is easier on a trolley than on a trailer.


If you are trailing any distance or if you ever intend to double deck two 5o5s on a single trailer, you should get larger wheels and tires. The normal 12 inch diameter tires are OK, but larger tires reduce the turns the bearings have to do, and give a smoother ride. I think they run cooler as well. Always check your tire pressure. A trailer tire low on pressure will rapidly overheat, and can easily blow out.


Both the English Rapide bearings and the North American style bearings normally last well in normal use. DO NOT PUT THE TRAILER IN THE WATER! Water in the bearings will rapidly destroy them, leaving you by the side of the Interstate at 2:00 am! Get yourself a dolly and leave the trailer on dry land!

Unless you are certain that the bearings are in excellent condition, do not use the trailer until you have the bearings checked and re-packed. New bearings and grease do not cost much; the consequences of not doing it could be you on the side of the Interstate at 2:00 am, again.

I add Bearing Buddies, a minor modification kit that slightly pressurizes the grease inside the bearing to North American trailers. I still don’t put the trailer in the water.

Trailer Options for North American 505ers

North American-style Trailers

Almost all North American trailers were not designed with light weight dinghies in mind. They are based on an axle and leaf springs, and some kind of flat framework. Some rollers that may work well for a 600 pound motorboat are bolted to the flat frame. Do not put your 505 on those rollers, they will punch through or at least damage the hull. These trailers can be converted for 5o5 use by building supports up from the trailer frame to support the boat where the Rapide trolley would support it. The full axle and leaf springs used by American trailers result in the boat riding considerably higher. Some people build or buy a trolley/dolly, and tie that to the trailer after they have grown tired of lifting the boat on and off the trailer.

Provided the trailer is strong enough, American trailers can easily have frames for double decking added.

Rapide Trailer-and-Trolly

The English-built Rapide trailer and trolley COMBI is an elegant solution. A number of UK trailer vendors have combis, but the Rapide is the only one imported into the US and Canada in any numbers. The Rapide road trailer is low and light, and the trolley is ideal for ramp or beach launching. The boat sits low on both the trolley and the trolley-on-trailer, so it trails well, and is easy to work on. The low height is achieved by using independent trailing arm/torsion bar suspension systems, and doing away with the conventional axle. Rapide has not provided any money to me for writing the above.

There are some challenges with the Rapide trailers though:

  • They are expensive, and have to be shipped over and imported (more cost and delay)
  • Rapide trailers do not have a serial number – this will make registering the trailer in your state rather interesting.
  • The Rapide trailer uses axle stubs that do not match any North American standard axles. You will have to buy replacement bearings at a bearing specialist, while hubs and wheels to fit the Rapide trailer have to be imported. I have used an American wheel-and-tire on the Rapide, though the mounting holes on the wheel were too large. The mounting nuts are conical and if the wheel is carefully mounted and the nuts tightened evenly, the American wheel/tire will be centered.
  • It can be difficult to find tires to fit the two sizes of Rapide wheel.

The registration issue is apparently most easily dealt with if you tell your state DMV the trailer is home built. While I have not tried this myself, a number of other Rapide trailer owners have told me about this. In some states they will issue a serial number to you. They may wish to inspect the trailer as well.

Copying the Rapide System

Given the cost of the Rapide trailer and dolly, copying it is often an option. The difficulties in copying this system is in finding the suspension units, and not being able to galvanize the complete trailer and trolly after welding. Provided you keep the trailer out of the water, you can just paint it, and just worry about stopping the dolly from rusting. You could import the suspension units from the UK, or find a North American source; these suspension units have been seen from time to time.

Some modified copies have been built with conventional leaf springs, though the trailer beds rode rather higher as a result.

Rondar Raceboats UK is now building trailer and dolly systems similar to the Rapide system.

Trailer Lights

Rapide trailers do not come with trailer lights, as they anticipate that you will use a lighting board hung on the transom. American trailers have the lights perfectly positioned to break off when you put the boat onto the trailer.

In my experience, the lighting board is the smart way to go. It puts the lights at the back where you want them (not 8 feet further forward, hidden under the hull!). It is easier to wire and keep working. Unfortunately, many states do not officially recognize the wisdom of this setup. US State’s DMV regulations were probably written by idiots with motorboats in mind. This may be a good place to point out that the opinions expressed by the author are his own, and not those of his employer, nor of the 505 Class, American Section.

Some people have installed lights on a Rapide trailer solely to get through their State trailer licensing/safety check process. They never use those lights, but plug in their lighting board when trailing.

I strongly urge you to do the lighting board. Resolving the matter with your state DMV is your problem.

By the way, most trailer lights shine a white light out to the side, so you can position your license plate there and it will be lit (that way, the policeman has a better chance to figure out who you are, as you zoom by). Or you can choose not to.

Chains and Spares

Despite my earlier comment regarding DMV regulations, many of them do make sense. One in particular is that you use trailer chains. Though it should not happen, trailer hitches do manage to come off by themselves once in awhile. If you do not have a trailer chain keeping the trailer near the hitch, the trailer – with your pride and joy on top – will go in whatever direction it pleases. Quite apart from the potential damage to your boat, a loose trailer on the highway could be extremely dangerous. Make sure you have chains, and use them! I have had trailers come off the hitch twice, and it has happened to others. In one case, the trailer did not have safety chains, and the loss of the boat and trailer was only noticed at the next gas stop! The skipper and crew drove frantically back along the highway, and found the boat on the side of the road, up against the light support it had hit. Fortunately, damage was not extensive.

Make sure you have a spare. Trailer tires do not last as long as car tires, and they overheat much more rapidly. Replacements are very hard to come by on short notice, by the side of the interstate at 2:00 am.

Supporting your Mast

Most people support the mast at the back on the lighting board, and near the front on a post rising from the front of the trailer. The mast sticks out back of the lighting board a very short distance, while it goes some distance forward of the post. Some people add a support rising out of the mast step to stop the mast flexing. This assumes you are towing behind a car not an SUV, as the mast is not supported high enough at the front to clear the higher roofline of the SUV. Another good solution is to roof rack the mast and maybe even the boom. Ideally, you support the mast so it does not flex a lot as you drive. You should pad whatever supports the mast, otherwise you might dent the mast wall.

Trailing Speed

Towing a trailer is always going to affect your automobiles handling, braking, and acceleration. The good news is that 505s are very light and rather streamlined. Even a car with a small engine usually has little difficulty towing a 505. A nice light, low trailer (like the Rapide) makes it even easier, and gives you better visibility behind you. Provided conditions are good, I tow at my normal driving speed. You should allow for the longer stopping distance though. It is my understanding that 505s on good trailers have been towed by small cars long distances at speeds in excess of 90 mph without any problem. No officer, it wasn’t me, I heard about it from someone else! (But feel free to use this in those inevitable “how fast is a 505?” discussions). I always drive 55, even when I’m going coast to coast non stop! 😉

Some More Thoughts

When considering trailer options, think about a double deck rig. If you plan to do any away events, a double rig will allow two boats to go together, giving you more drivers for longer distances, or allowing some people to fly.  It would also allow you to bring someone to an event who might not otherwise show up, very important for fleet building.

The double deck rig idea can be expanded. If you plan to do any distant events like a North Americans on the other coast, getting together with others in your fleet and acquiring a multi-boat trailer should be considered.

Rondar Raceboats has a six boat trailer that they often tow behind a car with a 2.2 liter engine. With six boats on it, the trailer has a lower center of gravity than the standard Rapide double rig. Imagine being able to show up at distant events with six boats from your fleet. Imagine that someone else drove and you got to fly! I am asking Rondar for the plans……