Nekton

Offering quick access to remote dive sites, a good boat is the ultimate diving platform: Catering to the full spectrum of underwater interests, the challenges are more exciting, the underwater visibility generally superior and the marine life more abundant than when diving from the shore.

A rapidly growing and highly competitive segment of the diving market, boat operators are tailoring diving packages to suit every level of experience, time frame and budget. Nowhere is this more apparent than in the Asia-Pacific region where new dive sites are being discovered on an almost daily basis.

Focussed more on the dive rather than the vessel that will carry them to the site, many divers make the assumption that a boat is a boat is a boat, and that as long as it floats that's all that matters. It's a widespread attitude. One that, certainly on the larger and more expensive liveaboards and day-boats, is encouraged by a level of comfort and care similar to that expected of a five-
star hotel or resort.

Not all boats, however, are created equal! Although the fundamental principles of boat diving remain fairly consistent, operating from a small vessel usually requires careful planning and much more attention to detail if it's to be a safe and enjoyable experience.

Choosing a Boat
There is no such thing as a standard dive boat. They come in all shapes, sizes and types, from small inflatables and traditional craft specific to certain countries or regions, through to purpose-built, custom-designed vessels. The thing that they should all share in common is their suitability as a diving platform and how well they're equipped to cope with a diving emergency.

Regardless of the boat's hull configuration and size, a prime consideration is its ability to safely handle the sort of sea conditions common to its area of operation? And then whether or not it can do so comfortably?

Many divers give little thought to their physical comfort. It is, however, an important aspect of safe diving practice. Small fast boats with no adequate protection from spray and wind chill - particularly in colder climates - are more likely to cause a dramatic drop in core body temperature; a bad way to start any dive and a condition that can contribute to DCS symptoms and exacerbate the effects of motion sickness! Alternatively, exposure to the burning rays of the sun will create its own set of problems, including sunburn and dehydration.

In most countries, commercial dive vessels are required to meet certain criteria. Specifying things such as what safety equipment is to be carried and where and how the vessel can be operated, there are usually also restrictions on the maximum numbers of passengers and crew carried by the craft.

In the context of diving, there's a huge difference between, "maximum" and "ideal" passenger numbers. This holds especially true when multiple cylinders are used and the divers require more space to rig and prepare for the dive. When kitting up in the cramped confines of a crowded boat, it's easy to overlook the small but vitally important details!

Getting quickly and comfortably to the dive site is important; returning safely and on time is even more so! Regardless of whether the boat is fitted with inboard or outboard engines, it's comforting to know that there's a back up should the primary fail. Motors that are badly maintained can increase a diver's exposure to carbon-monoxide fumes, while even small quantities of spilled fuel will quickly contaminate diving equipment. Where possible fuel should be stowed in a compartment separate to the dive deck itself.

The smaller the craft the more critical becomes the use of space. A good dive boat will be configured to allow for secure stowage of cylinders and ancillary items like masks, fins, weight-belts, reels and lights. In addition, it should also have provision for dry-
area stowage of small personal effects like towels, sunglasses and essential items of dry clothing.

Entering the water from a vessel rarely causes difficulties. Getting back on board again can, however, be more problematic! Methods for accomplishing this will vary, even between vessels of the same size and type. In some, it's a case of passing the equipment into the boat before hauling yourself in over the side; several use a semi-submerged platform; others employ a ladder. Even then it's worth remembering that not all ladders are the same; some have wide gaps between rungs and slope at an angle for climbing ease; others consist of a single bar with open-ended struts that allow divers wearing fins to easily negotiate the climb; still more consist of the traditional metal ladder hanging vertically from the side or stern. Whatever the method, ensure that, (in a worst-case scenario where divers might be required to exit the water quickly and with all of the equipment in place) it is within the diver's personal level of physical ability.

Different vessels have different routines and procedures. The diver might be the paying customer, but it's the skipper's boat. As the person responsible for the safety and well being of everybody on board, his directives should - within the bounds of reason and safety - be followed in terms of where and how equipment is to be stowed; the on-board procedures; when to enter the water, and all matters relating to the smooth running of the boat. This is not to suggest that all skippers are infallible, or that their actions are above question. The ultimate responsibility for a diver's safety rests with himself or herself. Where doubts exist about any of the procedures, raise and discuss them quietly with the skipper and crew. And if they're not resolved to the diver's complete satisfaction then abort the dive.

When operating from a larger vessel supporting many divers it is not always easy or desirable to quickly slip a mooring - or recover an anchor - and quickly go to the aid of a distant surfaced diver in distress. In those instances, it's far more practical to use a small chase boat, (in the water, fuelled up and ready to go) for this purpose.

Boat Equipment
Regardless of its size, a dive boat must be capable of responding to any emergency situation that arises - particularly one involving divers. In this respect the further the boat travels from land and other sea-borne traffic the greater the need for self-sufficiency.

For obvious reasons of safety all boats should carry certain basic items of equipment. These include, (but are not limited to); lifejackets in sufficient number for every person on board; fire-fighting equipment; tool kit; radio communications; navigation equipment, (e.g. lights, depth sounder, G.P.S.); signal flares and dye marker packs; a spare anchor and chain; weighted heaving lines, properly coiled and able to be quickly deployed to aid a distressed person on the surface; and plenty of fresh drinking water in either tanks or containers.

In addition, dive boats should also carry a properly stocked and regularly checked first-
aid kit; oxygen resuscitation equipment, (and at least one person qualified in its use); an adequate supply of oxygen commensurate with the time it will take to transport the patient back to land; a basic spare parts kit with all of the necessary tools; a current ('mermaid') line and float - a device that effectively extends the waterline length of the boat's

hull and provides a useful resting point for divers waiting their turn to exit the water; a diving flag - commonly international Flag Alpha - flown from vessels to indicate that divers are below. (It's also worth noting that there are regional variations in regulations governing how a vessel displaying a dive flag should be approached.) Where space permits, it's also useful to have a complete set of rigged diving gear maintained in working order and ready for use.

"Plan your dive �"
With so many variables to consider, planning a boat dive requires great attention to detail. Having ascertained the purpose and type, (wreck, reef, photography, etc.) of the proposed dive, gather as much information as possible about the site and talk with others who've previously dived there. Because of weather conditions, sea states, or other dive craft crowding the area, it may not be possible to dive the preferred destination. Plan for this by applying the same research to an alternate site and make certain that the depth - together with any peculiarities associated with the dive - are within the limits of the diver's experience and training.

With a vested economic interest in running as many trips as possible, some commercial dive boat operators are inclined to push the envelope of safety and comfort! Before boarding a boat check the weather and shipping forecasts. Where doubts about the expected conditions exist, always err on the side of caution. The sea will still be there tomorrow! Confirm in advance of boarding any time or depth restrictions placed on the dive. A majority of commercial dive boats operate to tight schedules and place time constraints on dive durations.

The smaller the boat the less space there will be for non-essential items. As with all forms of diving, take with you only that equipment necessary to the safe performance of the dive, and limit other items to those things necessary to preserve warmth and comfort while on the surface. These might include a towel, hat, wind-
breaker or otherwarm top and, where relevant, sun-
glasses and sun block.

Ensure that somebody on shore knows where you are going; the name of the dive operation, the boat, the people that you're travelling with, and what time you expect to return. Compile a list of emergency contact 'phone numbers. These should include details of which authorities to notify in the event that the vessel is overdue, local search and rescue organizations, relevant diving emergency organizations, (Divers Alert Network?); and the location of the nearest recompression chamber catering to recreational divers. Carry a copy of this information with you and leave another with a responsible person on shore.

Unless diving with companions of your own choosing, observe the other passengers on the boat and, as diplomatically as possible, try to separate the wheat from the chaff in terms of their training, their experience and - more importantly - their attitude towards the dive! On some vessels, divers travelling alone are often assigned a buddy by the skipper or dive-master. If you feel anything other than completely at ease with the choice of buddy - and unless you can agree on a dive plan based on the abilities of the least experienced - then either make alternate arrangements, or abort the dive. (This should be done as tactfully as possible to avoid giving unnecessary offence. Confrontation in a small boat serves no useful purpose, especially when simply feigning illness can serve the same purpose!)

Familiarise yourself with the boat and the location of safety and emergency equipment. No matter how often you've travelled aboard that particular vessel, or how many times you may have dived a particular site, pay attention to the dive briefing and make doubly certain that the proposed dive is within the capabilities of both yourself and those with whom you'll be diving.

Confirm the method of entry and exit from the water and also ensure that at least one person remains on the boat. First, to act as a lookout for surfacing divers who may be in distress or some distance from the vessel, but also to ensure that the craft doesn't - either by design or accident - stray from where it's supposed to be!

Surfacing divers may find that wave action or strong currents have carried them away from the boat. Although a rare occurrence, there are instances when the boat is required to slip the mooring, (to attend, for example, to a nearby emergency) before all of the divers have been recovered. In situations like these, divers should make themselves buoyant and, rather than attempting a long and exhausting surface swim, wait for the boat's return.

In an emergency situation, it might be necessary to recall the divers. A simple method is to continually bang on the dive ladder with a suitably heavy object, (a hammer, monkey wrench, or even a dive weight). The sound will be amplified under the water and can travel great distances.

Review the dive plan with your companions and ensure that everyone in the team is familiar with: its purpose; the route to be followed; the depth, time and gas supply parameters; turn - around points; communications; emergency procedures; and who will lead the dive. This is also the time to discuss any doubts or concerns about the dive. Reinforce the fact that any diver can, at any time and for whatever reason, call

Assist each other during the gearing up process and ensure familiarity with one another's equipment by carrying out the pre-dive checks followed by the final, "OK"; an indication that the divers have confidence in their ability to safely perform the dive according to the plan.

"� and then dive your plan!"
Only enter the water when the skipper, or appropriate crewmember, says that it's safe to do so. Unless 'live-boating' on a drift dive, this will usually be once the vessel is moored and the engines turned off. Check the entry area for any

Although the type of dive and sea conditions govern the approach taken, it's common practice to enter the water positively buoyant with the BCD partially inflated. After signalling an, 'OK' back to the boat, make any final equipment adjustments, check that your buddy is ready and then begin the descent.

An anchor - or weighted shot line - provides a useful reference point during descent. Especially in areas of reduced visibility and deep water where the sea floor cannot be seen, or when a current is flowing. It also acts as a comforting psychological link with the surface for divers who may have overly exerted themselves during the entry phase and who need to bring their breathing pattern back under control before continuing the descent. Because dives are generally planned to begin at, or close to, the seafloor, the use of a descent line also helps dive teams stay together.

When diving from an anchored vessel, the first divers down should check that it is properly set. Once at depth, or on the bottom, rest easy for about 30-seconds or so, settle down and take note of the surroundings. Bearing in mind that a bottom flowing current can run counter to that experienced on the surface, confirm its strength and direction against the compass. Ideally - and particularly when diving over open terrain - begin the dive into the current and on the return leg use its energy to return as close as possible to the dive's starting point. The more proficient the diver is in both compass and natural navigation techniques, the easier this is to achieve.

The ascent - regardless of whether it's made up an anchor or shot line, or in blue-water after deploying a Surface Marker Buoy (SMB) - should be made slowly while maintaining neutral buoyancy. Concentrate on exhaling fully and properly, and constantly monitor the depth gauge. Carrying out a safety stop while clinging to a bucking anchor line can be a very uncomfortable business. Good buoyancy skills allow the diver to maintain a constant depth and are less exhausting.

During the final ascent, look up and, especially in poor visibility, raise one hand above the head to avoid collision with any obstructions. Listen for engine noise from approaching boat traffic. On the surface make yourself buoyant, check your buddy, signal an OK to the boat and then follow the crew's directions for exiting the water. Keep all of the gear in place until it becomes necessary to remove it, or until back on board. In a choppy sea it's easy to breathe in water if the regulator's been removed.

Something as seemingly simple as a coughing fit on the surface can easily escalate into full blown distress, or cause the diver to drop a facemask or fins. Once safely on board, follow the crew's directions in terms of disassembling and stowing the equipment.

Being prepared
Boat diving is fun. It's made more so when the diver exercises care over the choice of a vessel; is competent in the basic skills; has good buoyancy control; is proficient in underwater navigation techniques, and understands that, 'Today's dive starts the night before'!

Remember that there's no such thing as an, 'easy dive'! Without adequate sleep and rest, eating sensible meals and being well hydrated, what should otherwise have been an enjoyable diving experience has the potential to become a wretched disaster.