Fuel capacity usually isn’t an issue in home waters, but it becomes important when long-range cruising sailboats have to motor for extended periods. The common solution is to carry jerry jugs, but flexible tanks or bladders that are carried on deck and can be stowed away when empty are well worth considering. Historically these have had a mixed track record, but the technology is now fairly mature.
A good example is the “Super Deck Tank” shown in the photo, which is specifically designed to carry diesel fuel and, according to the manufacturer (turtlepac.com), can survive a drop of over 30 feet. The inner bladder is electronically welded and protected from puncture, chafe and sunlight by two outer envelopes with double-welded and stitched seams. Reinforced stainless steel grommets and webbing tie-down loops are sewn to the outer envelope. The tanks have an anti-surge harness with an adjustable stainless buckle. The inner bladder can be accessed through a flap and is removable for inspection, repair or replacement. All in all, it seems a rugged bit of kit.
A great advantage to having this kind of auxiliary stowage capacity is that fuel can be gravity-fed straight from the bladder into the main tanks via their deck fills. No more handling messy jugs. Capacities are also deceptively generous. The small bladder in the photo holds over 50 gallons—equivalent to about eight jerry jugs. Given suitable lifting tackle, a flexible bladder can also be carried in a dinghy to a refueling point that is inaccessible to the yacht, such as up a creek to a gas station that has cheaper prices than the local marina.
Photo courtesy of Turtlepac