Thames A Class Rater (scow)

The Thames A Class Rater is both a historic and modern specialist sailing craft designed for the particular conditions at Thames Sailing Club, on the River Thames at Surbiton in England. The rules [ [http://www.thamessailingclub.co.uk/37097/Raters/Rules.aspx Rules of the The Thames "A" Rater Association] ] refer to the craft as a yacht.

The rig is lofty, supported by standing rigging and usually by runners [A runner is one of a pair of running backstays. It is rigged between a point towards the boat's quarter and one usually fairly high on the mast. That on the windward side is tensioned to support the mast against the drive of the wind on the sail, while the leeward one is slackened to permit the mainsail to take an efficient shape. So that the tensioning and relaxation can be done rapidly as the boat goes about, a highfield lever is normally used.] , and the hull is a scow with metal centreplate.

The rater is extremely fast, planes easily, and is a technically highly challenging boat to sail in anything above moderate wind conditions. It is usually sailed with a crew of three.

Raters have traditionally commuted by river under tow between Thames Sailing Club at Surbiton and Upper Thames Sailing Club at Bourne End, Buckinghamshire.

ailing conditions

The home water was originally upstream of Raven's Ait, where the right bank of the Thames is a 15' (4.5m) high, mid-nineteenth century brick wall, designed to separate the river, even in spate, from the spring water of the Seething Wells waterworks. The left bank has tall mature plane trees. These enclosed conditions often result in unusually light wind conditions with variable eddies unless the wind direction is directly up or downstream when it tends to be funnelled along the river. The approximate boundaries of the water were from Gbmapping|TQ174678 (Thames Sailing Club race start line) upstream to Gbmapping|TQ154684 (Hampton Court Palace).

Over the years raters have developed extraordinarily tall masts and high aspect mainsails to meet the local conditions, and catch the wind above the trees and other obstructions along the banks. Their sails were always large, but originally they had long booms and shorter masts, but over time the booms got shorter and the masts taller. At first they used the so-called balance lug rug, then the Gunter rig, before moving on to the current Bermuda rig. Over the years bamboo spars were replaced first by wood, then aluminium, and now mostly carbon fibre.Fact|date=February 2007

Where raters sail

Thames Sailing Club

The original home of the rater

Upper Thames Sailing Club

Regattas

Mixed in with large fleets of other boats, the raters are usually seen at the following regattas with very tight, close quarters racing.

*Tamesis Easter Regatta - Tamesis Club at Gbmapping|TW177707, racing between Teddington Lock and Kingston Railway Bridge.

History

Boats past and present

The source data for this section is, in part [http://www.thamessailingclub.co.uk/E0760/Raters/Rater_Descriptions.aspx Rater Descriptions] from The Rater Association

In the table, "d:" refers to the designer, "b:" to the builder. Where simply a name is present that is the builder

Handicap

Unusually, for a class designed about a rule allowing wide variation in most design parameters, individual boats are handicapped.

:"Handicaps will be determined by a handicap committee consisting of the Rater Captain, plus the fastest and slowest helms in the FRP ["FRP" is used instead of "GRP" because at least one boat, Tara, is carbon fibre reinforced. Hence "Fibre Reinforced Plastic"] and wooden fleets respectively, based on the results of the most recent Thames Championship. In the event that the Rater Captain is one of the latter four, the closest helm to the Rater Captain in their category shall also be co-opted to the committee."

:"This committee will meet two or three times a year to decide the handicap of all boats."

:"The overriding principle that the committee will work to is to encourage the older and slower boats to compete."

The Association

Thames "A" Rater Association
Thames Sailing Club
Portsmouth Road
Surbiton
Surrey
United Kingdom
KT6 4HH

References