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UKOPRA Class Classifications

UKOPRA Class Classifications


In order to advance environmental solutions horsepower can be derived from any form either stored as fuel or generated.

For the avoidance of doubt the measurement of horsepower should be based upon 0.746kw per hp. Power output measurement of non-standard reciprocating motors will be at prop shaft and determined in accordance with ISO 3046 at crankshaft with a 5% allowance for drivetrain loss.

In accordance with Icomia any test will not exceed 105% of the declared horsepower.

Standard production motors can be declared as the manufacturer prop shaft horsepower and must be submitted for technical inspection to ensure no change from manufacturer specification has occurred.

All power plants will be sealed at the beginning of season and must not be altered at any time without technical scrutineer approval.

Where the race requires a minimum of two propulsion units any auxiliary unit not intended for use during the race does not require to be declared a part of overall power.


Minimum weight for the boat will be calculated from the declared horsepower in accordance with the table and must be declared before the start of season.

Weighing will be carried out after the race and solely at the discretion of the technical scrutineer.

The declared minimum weight will be of the craft, crew, equipment and residual fuel in the condition it passed the finish line, and any collected ballast must be drained prior to weighing.

The measured weight must be more than 97% of that declared when measured with UKOPRA certified equipment.

To facilitate the weighing of craft all craft must carry suitable and certified slings to achieve a single point lift.


The craft length will be measured between perpendiculars of the external moulded length of the boat, taken at the extreme bow and the interface between the hull and bracket/engine/drive.


The minimum weight for each boat will be increased by the tabulated figure for the amount of length over and above that stated.

For example, a 15m boat of 2000hp within Class 1 will be applied as 3.3 plus 3m x 0.15 equals 3.75kg/hp.


The beam ratio of a monohull is determined as the ratio of the overall width of moulded surfaces divided by the width between chines. I.e., 2.4 divided by 2.0 equals 1.2.


Monohulls exceeding the beam ratio are determined as assisted lift monohulls and minimum weights are defined as monohull weight increased by the stated percentage.


Multihull minimum weights are defined as monohull weight increased by the stated percentage.

Multihulls are reintroduced to classes 1 and 2 for 2022 and the UKOPRA committee reserves the right to monitor their safe reintroduction and amend requirements for them at any time during the season.

Multihull will be strictly a clear flow tunnel with no form of compression allowed within or behind the tunnel.


Buoyancy of craft is the express responsibility of competitors, and it is recommended to carry sufficient to keep a boat afloat in the event of hull damage.

Boats that cannot achieve the minimum buoyancy can alternatively carry a life raft sufficient to support the whole crew. Life rafts are mandatory on some races and will be notified in race instructions.


Cube dimension sizes are determined by ensuring a box of the dimensions quoted can be accommodated within the external hull fabric of the dimensions shown. Internal structures are ignored for the purposes of the rule.