Optimist (dinghy)

The single sail of the Optimist is sprit-rigged. Two battens stiffen the leech. It is secured evenly with ties along the luff to the mast and along the foot to the boom, pulled down tightly by a vang/kicker. The light, slim third spar, the sprit, extends through a loop at the peak of the sail; the bottom rests in the eye of a short cable or string which hangs along the front edge of the mast. Raising and lowering the sprit and adjusting the boom vang allow for adaptation of sail trim to a range of wind conditions. Similarly, the Optimist has a small string outhaul on the end of the boom. It is usually correct to tighten the boomvang, outhaul, and sprit in heavy winds and loosen them in light winds. As well as this, huge adjustments can be made to sail shape, due to all of the ties running along the mast and boom.

The spars may be made from aluminium or wood, but are invariably aluminium in modern boats.

A monograph-style "IO" insignia (after IODA - the International Optimist Dinghy Association) on the sail is a registered trade-mark and may only be used under licence from the International Optimist Association. Optimists also have a national sail number using the Olympic abbreviation of their country and a sequential numbers. e.g. RSA for South Africa.

The Optimist has a pram hull, originally formed primarily from five pieces of plywood. It was the biggest hull Clark Mills could make from two 4 ft by 8 ft sheets. Just in front of a bulkhead, which partitions the boat nearly in half, is the daggerboard case. Right behind it on the centerline of the hull floor are attached a pulley and ratchet block. These anchor the sheet and its pulley on the boom directly above. At the bow resides a thwart to support the mast which passes through a hole in its centre to the mast step mounted on the centre line of the boat. The painter, a rope used for securing a boat like a mooring line, is usually tied around the mast step.

Buoyancy bags are installed inboard along each side in the front half of the boat and at the stern to add buoyancy in the event of capsizing. Two straps, known as "hiking straps", run lengthwise along the floor from bulkhead to stern. These and a tiller extension allow a sailor to hang off the side for weight distribution—commonly called "hiking out". This can be crucial to maintaining the boat in near horizontal disposition during heavy air, allowing greater speed through the water and more manoeuvrability.

The vast majority of hulls today are made of fiberglass,[9] although it is still possible to make and buy wooden hulls.

The rudder and daggerboard can be made from plywood or a composite of foam, glass fibre, and epoxy.

While younger lighter sailors begin in Optimists, competitive sailors usually weigh between 35 and 55 kg (or between 80 lbs. and 125 lbs.).[10] Optimists can be sailed by children from age 8 to 15. This wide range of weights which is not typical of most dinghies is made possible by different cuts of sail. Due to its inherent stability, unstayed rig, robust construction and relatively small sail, the Optimist can be sailed in winds of up to 30 knots.

Optimists are manufactured to the same specification by over 20 builders on four continents. There is strong evidence[11] that hulls from different builders are the same speed. Sails and spars of differing qualities enable sailors to upgrade their equipment as they progress.

The Optimist is the slowest dinghy in the world according to the RYA Portsmouth Yardstick scheme, with a Portsmouth number of 1646.[12] Its equivalent rating in the US scheme is a D-PN of 123.6.[13]