Antifouling orders in Dubai chandleries are mostly guesses rounded up, which wastes money, or rounded down, which costs a thin second coat exactly where the season is lost. The wetted area method takes five minutes and gets the order right.
Step one: estimate wetted surface area
For displacement and semi displacement hulls, a serviceable estimate is waterline length multiplied by beam plus draft, multiplied by 0.85. For a boat with 11 metres on the waterline, 4 metres beam and 1.2 metres draft: 11 x 5.2 x 0.85, roughly 49 square metres. Full keeled yachts trend a little higher, light fin keel racers lower; catamarans calculate per hull and add the bridgedeck wetted margins.
Step two: convert with the real coverage rate
Use the practical coverage from the antifouling data sheet, not the theoretical number; rolled application onto aged antifouling absorbs more paint than the laboratory figure suggests. Self polishing grades commonly cover 8 to 10 square metres per litre per coat in practice. Our 49 square metre example at two coats: 49 x 2 / 9, roughly 11 litres, before stripe coats.
Step three: add the stripe coat allowance
Waterline band, leading edges, rudder, keel foot and trim tabs polish fastest and earn a third pass. Allow 10 to 15 percent extra. Our example lands at 12 to 13 litres: a 12.5 litre order, not the 20 the counter guess would have produced, and not the 10 that leaves the second coat thin at the waterline.
The details that change the answer
Bare or freshly stripped hulls drink a sealing first coat. Colour changes need full hiding, budget accordingly. And unknown existing coatings need a tie coat line in the same order.
Send waterline length, beam and draft on WhatsApp and MENA Industrial Supplies returns litres, scheme and price the same day from the marine range, delivered anywhere in the UAE.