KEELBLACK is sold in 5 litre and 25 litre kegs. 15 litres will give at least three coats to a 72 foot narrowboat or widebeam, 10 litres for a 50 - 60 footer and 5 litres for anything below 45/ 50ft . This is based on treating the sides of the hull, gunnel to chine, but not the bottom. For hulls with a glossed strip, above the top rubbing strake, allow approximately 20% less. If you are uncertain please contact KEELBLACK for specific advice before you buy. We reccomend three coats but any surplus can be applied as a 4th coat above the waterline. NB any additional coats applied below the waterline will result in longer curing time - ensure your relaunch date allows you sufficient time for curing. We aim to save you money!