Trailer sailer

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Trailer Sailer Farr 7500

A trailer sailer is a small yacht or large dinghy style of sailboat that is moved to sailing locations and stored on a road trailer. It is neither a Day sailer or a Pocket cruiser but may be used for either purpose depending upon design suitability. The large dinghy style relies principally on correct crew weight for balance rather than fixed ballast, much like a dinghy and is suitable for use only on protected water. The other style is a Trailer yacht, which has a proper yacht ballast ratio of at least 30% excluding crew weight. This latter style is suited to yacht racing or cruising on inshore waters and along coastlines; a good example may pass self righting tests and be suitable for Junior Offshore Group (JOG) or Channel events or the like. Other designs are a compromise between the two principal types. An emerging type is the Sportsboat with a proper yacht ballast ratio, but large sail areas requiring crew weight positioning for stability, with their own design and self righting rules.[1][2] One feature that distinguishes Trailer sailers from other small yachts is the need to launch from and recover to an on road registered trailer, which can place constraints on dimensions and weights. They may vary in length from 5 to 10 meters; 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 not fixed but may be retracting, removable or swing, hydraulic, winch or electric operated and the ballast may be water that is drained to reduce weight for trailing. For reason of weight saving they are more likely to have a removable outboard engine.

By inherent design those with lifting keels can approach a beach or landing and occupants wade ashore, great for family outings, and if necessary they can sit the bottom comfortably. Shallower cruising grounds can also be more readily accessed, for these reasons and for costs, as they can be stored on the trailer at home or at a marina, they are popular with young families. Another advantage is the quick movement between different cruising grounds, it may take weeks to sail a yacht whereas only days to road transport across a country.


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. Including the number and type of berths, galley equipment and water storage, even if 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 then different self righting specifications will have to be met, in the design. Each trailer sailer design however is a compromise between racing ability and cruising comfort and stability.

Hull shape

In monohull yachts, hull shape is very much affected by measurement rules. See Hull (watercraft) To start with though the maximum length is restricted by road regulations on maximum widths, for above a length width ratio of 3:1 a yacht becomes tender, in that it will tend to more easily rock side to side, not comfortable. Waterline length is the determinant on displacement water speed, the speed in knots very roughly is proportionate to the square root of the waterline length in feet. So a 16 ft boat can do 4 knots and a 25ft 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 goes to cruising comfort. A 16 ft boat will not have standing headroom down below, because otherwise it would be top heavy not only weight wise but also windage wise. A 25 ft yacht might manage standing headroom. 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 or aluminium will likely have multiple chines, ridges where flat sheets join at an angle. 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 higher weight of glass, unless composites are used, not for the handyman. 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 meter waves and outpace larger displacement yachts up to twice their size. 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 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 and new rating rules will no doubt arise to compensate. Not to forget that the yacht hull must rise easily onto a trailer and so the forefoot is usually rounded and the hull should ride on rollers that do not need to be adjusted to get the boat on and off, so hull shape will influence trailer design and trailability.


To be trailable there is a limited number of alternative keels that can be used. In general there is the drop keel and the swing keel with variations on each. Bilge keels as found on pocket cruisers are considered too inefficient for trailer sailers. For any keel that retracts into the yacht a centreboard case to house it is required inside the yacht. These days for drop keels full cabin height cases are usually required under safety rules. Swing keel cases can sometimes be kept beneath floors and so not intrude into the cabin space, but are considered less efficient than a drop keel which can have an aerofoil section. Although keels must be locked down when racing outside, many believe the swing keel has safety advantages for if it runs aground (assuming not racing!) the keel will kick up and either slide over an obstruction or slow the boat, whereas a drop keel will stop and pirouette a yacht abruptly. However a drop keel can be sailed with the board partly raised without upsetting the centre of hull resistance and balance of the boat. To some a swing keel is a liability for if the yacht capsizes without the centreboard fixed, when inverted the board can swing in and damage the case top, leaving a leak below waterline assuming the boat can be righted. Whereas a drop keel yacht with full height case is not a liability in such extreme circumstances. To enable sailing with the board partly raised, practised where allowed downwind, to reduce wetted surface area, or when cruising over shallows, yachts will sometimes carry extra ballast beneath the floors fixed inside the hull, or use a large bulb at the bottom of the board that contains most of the weight. Self righting tests are sometimes specified for such arrangements.


The rig is the mast and stays or rigging to keep it in place. Because of trailering the need is for it to be raised and lowered to the deck easily. On smaller sizes this can often be manhandled by one or two people but in larger boats mechanical assistance is required. On pure racing boats light tall whippy masts are used but these require running backstays to keep them up, and must be changed each time a boat tacks or jibes. These definitely are a hindrance to short handed cruising. The argument is that whippy masts can be twisted off more to unload more air and maintain drive. The counter is with proper ballast as much air does not have to be dumped upwind and the bonus of a stiffer section is that a mast head spinnaker can be flown downwind to compensate. So trailer yachts designed for racing and cruising are more likely to have relatively heavier section masts, without running backstays and these do require a method to raise and lower. Many ingenious systems have been developed, for the mast must be steadied both longitudinally and sideways whilst raising and lowering. Ideally the side stay connections remain in place so that on raising a mast tuning is not altered each time. Trailer recovery winches can be utilised to raise the mast and spinnaker poles double as hoisting derricks, there are many variations.

Sail plans

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Trailable Yacht powering under asymmetrical spinaker, headsail 'furled'

The concept is that dad races the yacht with the crew on weekends competitively. Next weekend or on holidays the family, mum and youngsters cruise short handed. To achieve this safely often requires a reduced sail plan. 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 sail under main sail alone if need be. The headsail can be on a furler to reduce sail or furl away easily without the need to go onto the foredeck. However furler sails are not as efficient for racing, so a separate sail may be needed for this purpose. A useful alternative seen on these types of yachts is the self tacking headsail. Asymmetrical spinnakers are a useful addition for cruising as they are easier to tack, and a short bowsprit aids the use. But both bowsprits and asymmetricals may bring penalties in race handicaps if carried with symmetrical spinnakers. So the sail wardrobe should be flexible to enable different sails for cruising and racing.


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Trailable Yacht on trailer, small fixed keel yacht

Probably the most neglected part of a trailer sailer is the trailer. Trailer sailers of 8 meters in length say 26.5 ft, can weigh in at 1.5 to 2 tonnes and a trailer another ¾ tonne. So all up weight will determine the type of vehicle needed to tow them, but more importantly affect the design of the trailer. Multi-axle is preferred for on road safety and wheels should ideally match the tow vehicle for extra spares. Smaller diameter wheels can aid launching but are a liability for highway hauling. Trailer brakes will be needed and in some countries trailers of this weight must be fitted with breakaway automatic braking. That means either electric brakes or hydraulic/vacuum brakes with reservoir. These types of brakes have the advantage of remote (car) operation such 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 heavy passing or 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. The problem with boat trailer brakes is that they often get submerged in salt water, and corrode and degrade 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 are beginning to 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 seems to suffer from fatigue failure in this duty. Axles and wheel rims should ideally 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 simply a matter of removal of a few pins to reverse the carriage forward before launch. Special rear lights and connectors that can be immersed are also available. Wheel bearings need to be adequately rated for the load and best fitted with bearing buddies or the like and kept regularly pumped with marine waterproof grease, not auto grease. The roller system will depend upon 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. Whatever type of trailer, rollers should be regularly inspected, without the boat, and if need be replaced, polythene seems to be the most durable 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

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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 or makes of trailer yachts relative to each other from the performance of the best of their type in special mixed trailer sailer fleet regattas. Usually prepared and 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


External links