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Hull shapes - displacement and planing

Two types of hulls, generally speaking: displacement and planing. For SUPs:

Types of hull geometry:

When it comes to Jetskis, they often combine multiple hull shapes for the desired balance.

Flat-bottomed hulls are prone to “slap” or pound itself over waves – particularly at speed – and due to the minimal surface area, are typically “looser” or harder to control; requiring constant steering correction by the rider. GTI’s are marketed as being “loose” and “playful,” allowing the rider to freely “spin-out” on demand and generally goof-off far more than the Ultra.

The solution to maintaining the balance of a flat-bottomed hull while retaining the tracking and handling of a V-shaped hull has been found by reducing the deadrise and adding strakes to provide compensating lift. While chines can generate some lift, they are primarily used to manipulate how the hull will behave in a turn.

SUPs are measured by length and width. For example, a SUP can be 12’ x 24”, which means it’s 12’ long and 24” at its widest point. Most SUPs races are limited in length to 14’, so this is an effective upper bound for hull length.

Seems like for a powered SUP, a planing hull will be easier to get out of the water.

My understanding of the theory behind planing vs. displacement hulls is that a planing hull is slower at low speeds but once it starts to plane at higher speeds, it lifts out of the water and reduces the wetted surface, lowering friction and allowing higher top speeds – Robert Stehlik

References