Boat Design

Length-beam ratio


L/B = length divided by beam.

Units: Dimensionless.

Usually, the waterline dimensions LWL and BWL are used for monohulls, or for a single hull of a multihull.

What it's used for


Larger L/B indicates a slimmer hull. This usually implies less wave-making resistance, and thus more efficient high-speed performance, but also suggests reduced load-carrying ability for a given length.


Wetted surface area


Wetted surface area is the total surface area of the hull and appendages below the waterline. It should include both sides of the rudder and keel, and if the boat has multiple daggerboards, the given wetted surface area usually includes as many foils as would be used simultaneously.

Units: Area (usually square metres or square feet).


Model testing the Almaguin, part 5: Detailed behaviour

In the last few entries, I've covered the construction of the framework and hull for the Almaguin 400 test model, the towing rig, and some videos of the boat's behaviour. In this final episode of the series, we'll take a detailed look at what we've learned about this boat's behaviour from the model tests.


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