Trailer sailer

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Farr 7500 Trailer Yacht

A 'Trailer sailer' is a sailing boat that offers very basic accommodation, and is easily transported on a trailer. It is neither a Day sailer or a Pocket cruiser but can be used for either purpose depending upon its design. Trailer sailers rely principally on crew position and weight for balance like a dinghy and are suitable for use on protected waters. Trailer yachts are very similar but have overnight accommodation, a galley, head, a self-draining cockpit and are self-righting. Trailer yachts have a higher ballast ratio than a trailer sailer, and perform like a yacht when under sail. Trailer yachts are suited to yacht racing or cruising on inshore waters and along coastlines; and pass self-righting tests to be suitable for Junior Offshore Group (JOG) or English Channel events or similar. Sportsboats are outright performance orientated trailer yachts with minimal or no accommodation. They typically are constructed from exotic materials and boast large sail areas and asymmetric spinnakers. Sportsboats have their own design and self-righting rules.[1][2]

One feature that distinguishes Trailer Sailers, Trailer Yachts and Sportsboats from other small yachts is the ability to launch from a road registered trailer. In Australia the maximum permissible width for a trailer yacht is 2.5m (8'2"), however wider trailer yachts (for example RL34, Binks 30 & Noelex 30) are able to be towed using special wide-load permits. They may vary in length from 4.3 to 10 metres; above that the length-width ratio is not ideal. In addition the mast and rigging must be suitable for ease of raising and lowering. The keel is usually a swing or drop arrangement, with cast iron or lead ballast. More modern designs may use water ballast to minimise weight for towing. For reasons of cost, simplicity and weight saving most trailer yachts and trailer sailers are fitted with an outboard engine. Inboard diesel motors are available, especially for the largest trailer yachts, but are not popular as they are expensive, heavy and maintenance intensive. Inboard engines require either a drive leg or propeller shaft which is very vulnerable to damage during launching & retrieving and when the boat is operating in shallow water.

Trailer sailers & Trailer Yachts share the ability to approach a beach closely enough to allow the crew to wade ashore. They can usually take the bottom comfortably when the tide recedes ("drying out"). Trailer sailers and trailer yachts are typically stored on the trailer at home or onshore at a marina rather than on a mooring, thus making them easier and cheaper to maintain than moored boats and much less vulnerable to vandalism or theft. Another advantage is the quick movement between different cruising grounds: it may take weeks to sail a yacht to a new destination, whereas it may take only days to transport it by road. For example a trailer yacht can be towed from Sydney NSW to Airlie Beach QLD (approx 1900km by road) in the Whitsunday Island group easily within three days, with the crew sleeping in the boat like a caravan. To sail the same distance takes approximately three weeks, one way, weather permitting. It is not uncommon to spend a week caught in a port enroute on this journey waiting for a suitable weather window.


In this area trailer sailers, and particularly trailer yachts, are different from day sailers and pocket cruisers in that they are more likely to be designed for, or under the influence of, a measurement rule for yacht racing on handicap and overnight. Measurement rules not only determine the shape of a yacht but also affect the sail plan, and will even specify the accommodation requirements, such as the number and type of berths, galley equipment and water storage and even whether a head (marine toilet) is required. Depending on whether a yacht is to be raced in harbour (protected water) or outside along coastlines, or offshore, different self-righting specifications will have to be met in the design. Each trailer sailer design, however, is a compromise between speed and cruising comfort and stability.

Hull shape

In monohull yachts, hull shape is very much affected by measurement rules. See Hull (watercraft) In some countries the maximum width, length or weight is restricted by road regulations. Waterline length is the determinant on displacement water speed, the speed in knots very roughly is proportional to the square root of the waterline length in feet. So a 16 ft boat can do 4 knots and a 25 ft boat about 5 knots, not a lot of difference, unless you sail in tidal waters and face a 3 knot current where the larger boat will advance at twice the speed. The larger boat may also have 3 times the volume, which helps cruising comfort. Larger boats have more headroom.It is rare to have full head room in a boat smaller than 25 ft. Some trailer sailers have pop tops, a lifting canopy that gives full head room in smaller craft. The shape below the gunwales will be determined more by handicap measurement rules and these vary between countries. Also they will vary depending on construction method. Plywood kits and plans for plywood will likely be of single or multi chines construction. Fibreglass production boats will be very smooth and rounded and can include complex curves. This advantage in hull shape though can be offset by the much higher weight of glass, unless composite materials are used. The racing advantage that trailer yachts have when racing in mixed fleets is the ability to exceed displacement speed downwind on waves known as surfing. Most yachts will surf given the right conditions, often extreme, but for a light weight trailer yacht it may surf in the harbour on one metre waves and outpace larger displacement yachts up to twice their size.Lighter trailer sailers especially sports boats will plane in moderate breezes. Measurement rules which design yachts for all round performance have difficulty with this factor. For a normal yacht the less drag a hull has the faster it will go, particularly in light breezes and upwind, and here is the compromise, this usually means the stern of a yacht will decrease in width from the midsections aft. But this is not the ideal shape for surfing or planning where a wide stern with flat run aft is best. Thus trailer sailer hull design intended for racing will compromise upwind performance and rating for surfing and rating beating ability. Larger yachts are now following this trend. Trailer sailers are usually designed to spend most of the time on a trailer. The keel construction must be strong as it bears most of the weight of the hull plus crew. Trailers must be strong with multi rollers to assist in launching and retrieval. Smaller boat trailers use a geared winch of 1:3 or 1:5 while above 20 ft most use an electric winch.


In general there are two main arrangements for the keel, a drop keel or a swing keel, each with its advantages. A drop keel raises and lowers vertically (or at a slight angle). They are always used by performance orientated boats due to efficiency and the ability to fit a bulb. Bulb keels provide the lowest possible centre of gravity, maximising performance under sail. Swing keels pivot back into the hull and are more forgiving. Swing keels are very popular for cruising boats, but are considered less efficient than a drop keel because of drag created inside the keel case when sailing. The swing keel has major safety advantages for if it runs aground the keel will kick up and either slide over an obstruction or slow the boat, whereas a drop keel will stop the yacht extremely violently. This typically creates significant and dangerous structural damage to the interior of the centreboard case which can be very hard to find and very expensive to repair. A drop keel can be sailed with the board partly raised without upsetting the centre of hull resistance. However this is a dangerous practise as it raises the centre of gravity and badly upsets the self-righting ability of the boat. Sailing downwind with the centreboard or keel partly raised was briefly very popular because speed was increased due to reduced wetted area and considerably lower drag. However a series of accidents in the 1980's saw several trailer sailers broach under spinnaker while racing with the centreboard raised, resulting in violent knock downs. With the centreboard raised, these boats failed to self-right, and large waves swamped the boat through an open front hatch or an open companionway, resulting in rapid sinking. With very few exceptions, sailing with the centreboard raised is a dangerous practice and to be very strongly discouraged.


The rig is the mast and rigging. For ease of transport, the mast must be able to be raised and lowered easily. On smaller boats, one or two experienced people can easily raise & lower the mast. For larger boats mechanical assistance makes mast handling a pleasure. Novice sailors often struggle greatly with mast raising and lowering as they were not shown how to perform this correctly. There are two major types of rigs, masthead and fractional. On masthead rigs, the forestay and the backstay meet at the masthead. On fractional rigs, the forestay joins the mast a "fraction" of the way up the mast, the most popular being 3/4 rigs and 7/8th rigs. See the image of the fractional mast on the Farr 7500 above. On racing boats, taller masts of carbon fibre and exotic construction and more complicated rigging is used to optimise performance. Cruising boats typically use a light, uncomplicated aluminium mast. Purists often prefer wooden masts for their traditional appeal.

Sail plans

Trailable Yacht powering under asymmetrical spinnaker, headsail 'furled'

Most trailer sailers cater for a variety of uses. The ideal sail-plan for this is the fractional rig with the ¾ fractional being popular. Fractional rigs are where the height of the foresail only comes up to a fraction of the height of the mainsail. With these rigs the mainsail is the powerhouse and trimmed first, the advantage for cruising is that the centre of effort of the main sail in relationship to the centre of resistance of the hull is such that the boat will usually sail under main sail alone . The headsail can be on a furler to reduce sail or furl away easily without the need to go onto the foredeck. Furler sails may not as efficient for racing, so a separate head sail may be needed for this purpose. An alternative is the self tacking headsail. Asymmetrical spinnakers are a useful addition for cruising as they are easier to tack. A short bowsprit aids their use. Both bowsprits and asymmetricals may bring penalties in race handicaps if carried with symmetrical spinnakers. The sail wardrobe should be flexible to enable different sails for cruising and racing.


It is important to have a good trailer. Trailer sailers of 8 meters in length 26.5 ft, can weigh 1.5 to 2 tonnes and a trailer another ¾ tonne. Total weight will determine the type of vehicle needed to tow them, but more importantly affect the design of the trailer. Multi-axle is common in boats over 6 metres. Smaller diameter wheels lower the trailer making launching easier but are less suited to long distance highway hauling. Trailer brakes are generally fitted to larger trailers and in some countries heavy trailers o must be fitted with breakaway automatic braking.i.e. either electric brakes or hydraulic/vacuum brakes with reservoir. These types of brakes have the advantage of remote (car) operation so that the trailer can be braked separately and before the vehicle brakes. Stopping the rig with trailer brakes on only can quickly settle down fishtailing, caused by overtaking vehicles. It is also safer to brake the trailer first on slippery road surfaces to avoid jack knifing. Electric controllers are easier and cheaper to fit to towing vehicles but electric actuators at present can only be fitted to drum brakes, whilst hydraulic systems are needed for disc brakes. Boat trailer brakes often get submerged in salt water, and corrode quickly. Disc brakes are easier to inspect as drum brakes can hide corrosion, but both types are problematic mainly because automotive components used on trailer brakes are not designed for this duty. Stainless steel has been tried for brake discs, but is not ideal for it does not disperse heat well. Some manufacturers produce aluminium bronze brake discs for boat trailers which are much superior, combined with stainless steel or aluminium bronze callipers and stainless hydraulic lines, they can be immersed regularly in seawater without corrosion. There are also now electric driven/hydraulic pump units which can be fitted to boat trailers, enabling electric control of hydraulic disc brakes.

The optimum trailer chassis material seems to be galvanised steel, which should be galvanised inside and out with adequate drain holes in all members. Aluminium has been tried but may suffer from fatigue failure . Axles and wheel rims should also be galvanised steel. Axle carriages should ideally be movable on the chassis frame to allow adjustment in tow ball vertical load for stability optimizing. The compromise is that usually for hauling at highway speeds the carriage needs to go further back, but for launching and keeping wheels out of the water the carriage needs to be further forward. Some manufacturers have developed carriages on metal rollers within the frame, so it is a matter of removal of a few pins to reverse the carriage forward before launch. Special waterproof rear lights and connectors that can be immersed are available. Wheel bearings need to be adequately rated for the load and best fitted with bearing buddies and kept regularly pumped with marine waterproof grease, not auto grease. The roller system depends on the hull shape and should support the yacht at no fewer intervals that the internal rib spacing or at bulkheads in glass boats and coincide with them. Tilt trailers can assist in keeping wheels from being submersed each time a boat launches or retrieves, but some consider that such mechanisms are not easy to make tight on the drawbar and promote side sway on the road. Rollers should be regularly inspected, without the boat. Polythene seems to be the most durable roller material with different harder grades available for aluminium. Regular maintenance is vital for boat trailers particularly at the beginning of the season and before a long haul.

Racing and ratings

Trailable Yacht running

If a trailer yacht is to race outside of protected waters it will require a current Rating Certificate and likely also a Safety Certificate. Even if not built to a measurement rule, the boat will need to be measured to the rule stipulated in the Notice of Race to obtain a rating (handicap). For some national, international and other yacht racing events, rules such as those of the International Racing Certificate known as the IRC or the IRC sports boat rule SBR may be specified and are examples of such rules, others exist in different countries. Note that the measurement rules are different from the Sailing Rules which stipulate how races are run and the rights of yachts in different situations.

There are other handicap systems of a simplified measurement type designed to allow very different yachts of diverse designs to compete on an equal basis. This is particularly so for trailer sailers that may race in trailer sailer fleets or in mixed fleets. In some countries a Performance Handicap Racing Fleet or PHRF may be used to rate trailer sailers, such as in NZ and in the USA and Canada In other countries, the Class Based Handicap or CBH measurement system is used for trailer sailers, such as in Australia and also in NZ

Rather than from a measurement rule, Yardstick as in Portsmouth Yardstick is used in the UK is a way of rating different classes of trailer yachts relative to each other .These are adjusted annually at a state or regional level. At a club level, starting from a CBH or Yardstick rating a Performance Based Handicap or PBH may be used, such as PBH. This attempts to measure the relative performance of a particular yacht and crew against other yachts and crews either of the same type of other type. Clubs will often run an event or season championship based only upon a CBH rating together with a handicap winner based upon a regularly adjusted PBH figure for each yacht and crew. In theory the PBH which is adjusted after each race gives each boat an equal chance of winning each race.

Clubs, classes and associations

Trailer sailers organize within sailing clubs, as separate divisions if numbers warrant or may form completely separate clubs or associations, tailoring to both racing and /or family cruising. Some popular makes or classes of yachts also form, usually in a local region, a club especially for that make of boat. Participating in such activities, as invited crew is a good way of assessing the characteristics of different trailer sailers.

See also


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