Bridgedeck Clearance for Cats — Does it matter?
This exert has been taken out of Tony Grainger’s design catalogue. “The answer might seem obvious to anyone who has sailed bridgedeck cats offshore, but it isn’t so obvious to the newcomer to multihulls and one could be excused for asking the question when we see the proliferation of production cruising cats with relatively, and sometimes very low bridge clearance. Excessive clearance will create undesirable windage and it also increases the gap between the boom and the water, which is a major factor in reducing the efficiency of the rig from induced drag. However, it must be remembered that abridge clearance is reduced as heeling takes place and if the clearance is inadequate, safety, comfort, and overall performance will be compromised. So what does it matter? Wave slamming is most likely to occur upwind when the pitching of the boat interacts with the occasional steeper wave to cause slamming under the bridge. However, slamming can occur on any angle of sail including downwind and i
