Chapter 12- Boating, Diving and Seamanship Boating, Diving, and Seamanship 259 The third type of boat has a fiberglass semi-hull, mated to inflatable tubes. These are called RIBs, or Rigid Inflatable Boats (figure 12-2). These offer the best performance and the smoothest ride, but sacrifice two of the primary advantages of an inflatable: compact storage and light weight. Why would someone buy one of these instead of a comparably sized hard-hull boat that costs less? In a word, performance. RIBs are lighter than comparable rigid vessels, and their improved stiffness results in more speed than comparable non-RIB inflatables. They can use greater horsepower engines than other inflatables and use them more effectively. They can be more economical to operate by achieving good performance with less power. Their inflatable tubes make them more stable than conventional boats and virtually unsinkable. Regardless of which kind of inflatable you choose, look for maximum deck space. Avoid boats with intricate consoles, seats, and remote steering that sacrifice storage capacity. Diving gear has to go somewhere. This is an important factor to consider in any type of boat for serious divers. If this is going to be primarily a dive boat, some creature comforts may have to be traded for deck space. Diving procedures for inflatables are primarily the same as for any small boat. Be sure to fly appropriate signals such as a red and white dive flag, and blue and white navigational signal alpha pennant. They are required when diving off any boat, regardless of size. Since space is at a premium; cylinders, regulators, and backpacks should be assembled before leaving the dock. Everything on deck will probably get wet, so divers should wear wet suits and booties for the trip. Anything that has to remain dry, like wallets, fishing licenses, and lunch, should be packed in a waterproof container firmly secured to the boat. Ideally, everything not being worn should be secured by a line to the boat. Trim is important in any boat, as it can affect balance, handling, and seaworthiness. Arrange passengers and cargo to balance the vessel fore and aft, as well as port and starboard. The key is to have the boat plane, where it levels out and skims over the water rather than pushing through it. If the total weight approaches the engine’s capacity, the craft might not plane until some passengers move forward temporarily. Thus, crew members can serve as moveable ballast. Upon arrival at the dive site, cylinders should be put overboard, attached to a line. This will open a lot of deck space for final suiting up. The regulator should be attached to the cylinder valve and the air turned on. Jacket BC’s can be partially inflated to keep the scuba unit on the surface. A major advantage of an inflatable is its stability; more than one person at a time will be able to move around. Entry should be a backward roll or slipin, then the scuba units are donned in the water. Don’t forget to check the anchor on initial descent. Failure to do so could result in a long swim if the boat slips anchor while you are under water. It is best to leave a person in the boat. It is mandatory if there is a current or strong wave action. Also rig a current line and float if appropriate. When returning to the boat after the dive, remove the scuba unit in the water and attach it to the line. In a strong current, hook the cylinder to the line first, then take it off and pull yourself back in to the boat. Bringing the cylinders back on board and securing them for the trip home should be the last thing done before the anchor is pulled. OPEN SKIFFS Boats that are designed for fishing often make the best dive boats. Those designed for touring or water skiing often have reduced space and stability. Most skiffs are made of fiberglass, many with foam sandwiched between the layers to provide buoyancy. Hull design will determine the boat’s riding characteristics. Flat or cathedral hulls are generally very seaworthy but have a harsher ride due to bounce in short-interval chop. Deep vee hulls cut through the waves more smoothly but can be less stable at anchor and, because of their higher profile, may be harder to board, unless a platform or ladder is used. Welded aluminum boats with deep vee hulls are rapidly gaining acceptance, owing to their lower cost.
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