Boat diving is fun and fulfilling as long as it is well planned and proper deck courtesy is observed. Divers should be aware of what to expect in the dive spot and should be knowledgeable on the right ascent and entry techniques.

Want maximum fun and minimum hassle diving? Then, go scuba diving from a boat. Boats allow you access to the best dive spots, which are often too far away for shore access.

Boat diving maximizes your fun time and reduces the effort and problems of shore realities – such as traffic, parking meters, long walks with gear and long surface swims.

Generally, the farther offshore you dive, the better the conditions. Visibility is greater, the effects of waves and surge are less, animal populations are denser and the reef environment is more lush. If you are diving an area that has infrequent visits from sport and commercial divers and fishing boats, the underwater landscape will be more pristine.

Plan Ahead

Whether on a day trip or an extended live-aboard vacation, select an itinerary and boat that provide the activities you are seeking. For example, if you are afraid of seeing a shark, your first choice would not be Cocos Island. If you hate to see people spearfish, don’t select a California trip geared to taking game. If you think you might get seasick easily, don’t make your first boat dive a Coral Sea trip that starts with two days of continuous running.

Ask the charter office or travel agent booking your trip these key questions to see if your recreational goals match what the boat offers:

  1. Is this beginning, intermediate or advanced diving?
  2. What types of diving can I expect on this trip?
  3. What marine life can I expect to see?
  4. Are any types of diving prohibited, i.e., spearfishing?
  5. Is this guided diving or buddy diving without a guide?
  6. How does the boat crew adapt to different levels of divers and different activities on the same trip?

Be prepared to spend time on the boat. If you are motion sickness susceptible, take one of the over the counter remedies or get a prescription patch prior to boarding the boat. Once you start to feel seasick, it is too late for medication to work.

Also, adjust your diet to be more motion tolerant by reducing spicy and greasy foods. Drink more water than usual. It is important to be well hydrated and most adults don’t drink enough plain water on a daily basis. When you are outside in the wind or scuba diving and breathing dry air, your body needs extra water replenishment. Plain water is much better than soda or beer for hydration.

Take layered clothes and a hat so you can get warmer or cooler to stay comfortable. If you start to feel queasy, try to find a place on the boat with fresh air, where you can see a distant horizon. Stay low and near the boat’s center. Low and centered reduces the amount of movement and the horizon gives visual cues to help your other senses seek equilibrium.

If you do get seasick, please do it over the lee or downwind side of the boat. Don’t go below decks or to an inside head. No one else wants to clean up or smell the mess and the fish see it as a free meal!

What you should know about boat diving

Equipment Planning

Before you leave home or the hotel, action pack your dive bag. How to action pack changes with the type of diving you will do but the concept is to put the things you’ll use first on the top and the items you need last on the bottom.

For example, in warm water diving you may board the boat wearing a bodysuit, so the first piece of gear you will need is the buoyancy compensator to affix to a tank. On a local day trip, the first pieces of gear will be a swimsuit and wetsuit. The object is to never remove a piece of gear from the bag until you are ready to put it in place/use. The same principle applies in reverse when doffing gear – when you take it off, put it in the bag. Your companions sharing limited deck space will appreciate your dressing in and out of the gear bag, plus you have less chance of losing or breaking equipment. Mark your equipment with a dot of paint, piece of colored tape or your initials. It reduces accidental mix-ups and thefts.

Remember to bring spares and a replacement parts kit on a boat trip. Extra straps for masks or fins, O-rings, an extra mask, any small clips or lanyards that could be lost or broken are good ideas. Don’t forget your certification card, fishing license and logbook.

Deck Courtesy

Boats rock and roll constantly. If you leave a tank standing on the deck, it will fall over, injuring a diver or breaking something – guaranteed. Always put a tank on its side or fasten it in a rack whenever you take your hand away. It is also a near law of nature that if you sit on a boat deck to don your tank, your head will be at the same height as a standing diver wearing a tank and you will get clobbered. Sit on a bench to don your tank or have another diver lift it to assist you. The macho throw it over your head donning is poor form, too.

When you gear up, don everything except your mask, snorkel and fins. Do a buddy check, then move toward the exit point with the remainder of your equipment in hand. Use the mask rinsing well or bucket, don your mask, then your fins at the exit point. Don’t try to walk around on an unstable boat wearing fins. Try not to clog the exit area. Other people may be waiting and should not have to standby while you make last minute gear changes. These should be done before approaching the exit.

Taking The Leap

Anchoring a boat is not like parking a car. Boats don’t stay in one place. Boats swing on their anchors. The bigger the surface area of the cabin and the stronger the wind, the more the boat will swing back and forth. It will travel in an arc, pivoting from the anchor. The longer the anchorline, the bigger the area of movement.

Before you leap, tune into the boat’s movement. As it swings back and forth like a pendulum, you want to plan your entry. Jump when the boat is moving away from your entry point, not when it is about to pass over it. If there is a specific spot you want to dive, jump when you are on that side of the arc rather than waiting until you must swim all the way back. When diving from a big charter boat with a lot of scope on the anchorline, the distance from one side of the swing arc to the other might be a 10 minute swim!

Before you leap, look in the water. Is anyone just below the surface? Are you about to land in a clump of seaweed? If the water looks clear, look at your feet one last time. Are your fins on? Don’t laugh. Everyone jumps in sometime without his/her fins.

Once in the water, move away from the entry area. Either make a surface dive and descend well clear of the area or surface swim toward the anchorline. If you have hard to clear ears, use the anchorline as a guide to descend feet first, very slowly, clearing constantly as you drop. In poor visibility the anchorline provides a visual frame of reference that reduces the chance of vertigo. Remember that the anchorline stretches and relaxes as waves pass under the boat, so don’t be surprised when it moves.

Avoid skimming just under the surface. Skimming really makes it tough for other divers, other boats and your own crew to see you. Either swim on the surface or descend at least 10 to 15 feet.

Underwater Tips

Take the same steps to organize your underwater adventure as you would for any dive, including planned activities, direction, depth and time. Remember to start your dive swimming into a current, if one is present. This saves the easy ride for the end of the dive, when you are tired and low on air.

Use the boat to help you navigate and know your underwater location. Look in the water column for the anchorline. Check the bottom for the boat’s shadow or, on the surface, for its outline. Listen for the generator running – it gets louder as you get closer. Don’t get fooled, however, if the crew turns off the generator!

Sound radiates all directions underwater. So if you are using boat sounds to navigate and the sound gets fainter, don’t turn 180 degrees and go the opposite direction. Only change your direction about 45 degrees at a time, until you pick up a slightly increased sound level, then make another course correction. If you’ve never tried sound navigation, it is worth practicing on several dives. If you really want to make it a challenge, shut your eyes (no peeking) and try it. One buddy keeps his or her vision intact as the seeing eye so you don’t run into things!

A live-aboard boat has enough equipment running and people banging around that even if the generator is turned off, you can usually still hear mechanical sounds in between your exhales (which are pretty noisy themselves).

Back On The Surface

When ascending from a dive, don’t torpedo the boat bottom with your head! Ascend with the anchorline as a guide or use an ascent line and decompression stop bar, if provided. If your dive plan allows a direct ascent, watch and listen for the boat, so it does not swing on top of you at the surface.

Most boats trail a current line or tag line behind the boat in case you surface down current. This line typically has an inner tube or big float on the end, making it easier to spot. It swings with the boat, so assess which direction the boat is swinging, how fast you are moving in the surface current and whether you can wait for the current line to float over to your location. If you can’t wait, swim to the line.

There are two common techniques for using a current line. Try them both. One way is to grab a hold of the line, literally get right on top of it. Quit kicking and use arm strength to pull yourself back to the boat. Pull hand over hand, using short reaches as you glide over the line versus creating a slack line. If you try to kick your legs will get tangled in the line.

The other technique is to stay to the side of the line and continue with shallow kicks. Reach as far as you can above your head, grasp and pull until your hands reach between your hips and knees. Push the line away only when it is past your knees. You will create a slack line with this method and it is easier to get entangled.

Once nearly back at the boat, boarding techniques vary by the ramp/ladder setup. Stop a little way from the boarding ramp and check out the conditions. Is the boat plunging up and down so you could get hit by the ramp? In this situation, time your approach so when the ramp goes down in the water, you quickly swim onto it. You need to be firmly on the ramp when it begins its trip back up and out of the water.

Hand extra gear up to crew members or clip it to lines pre-hung over the side. There’s no need to climb a ladder while carrying a camera.

If the water is calm, most boats have you hang onto the ladder, remove fins and hand them up to crew members, then climb up the ladder. If there is any surface current or you fear not making it up the ladder, you may want to thread your fins on your forearm, keeping them available in case you fall back into the water.

Speaking of falling back into the water – it really happens. Don’t crowd beneath a ladder or someday you will get hit by a body, a foot or a tank that comes tumbling down. Let the person ahead of you clear the exit area before getting in line directly under/behind them. One of this author’s bloodiest diving injuries resulted from getting hit by a knife that slipped out of another diver’s BC pocket when he exited the water.

If the boat has a wide ramp, watch the timing and when it is slack or at a low point, swim as far up on the ramp as you can. Pull your knees underneath you and hold on for the upward ride. Stand up only after you have stabilized your position. Try to avoid rolling onto your side or getting turtled. You can actually stay in the kneeling position through a lot of rocking and rolling and not fall off a ramp.

Once back on the boat, take your tank off, secure it and mark it as needing a fill (this system varies from boat to boat). Take the regulator off, so no one can accidentally think it is a full, ready to use tank.

Take care of any game collected so it does not slime-up the deck or spoil in the sun. Undress into your gear bag so it is action loaded for the next dive. If you have handed mask and fins to a crew member, claim your gear promptly from the fin pile. This avoids mixups and chaos when you dress for the next dive.

When your cleanup chores are done, log your dive and enjoy the special time after a dive. I call it basking in the dive glow – the wonderful, exhilarating high of recalling the unique and beautiful things you have seen. It’s the pleasantly pooped feeling of contentment after an adventure.

Final Details

When you are ready to depart a dive boat, police your bunk and the galley for personal belongings. Settle your galley or bar tab. Remember the hard working crew with a tip, if you have appreciated their service, and remember to say thanks.

Diving from a large boat is easy, safe and enjoyable. Once you try it, you’ll like it. It is a simple way to make three or four dives in a day and maximize your recreation time. There are many very professionally operated charter dive boats for day trips and extended stays around the world. Once you try live-aboard vacations, you will probably be hooked for weekend and longer trips. A week aboard a well-equipped dive boat on calm seas, with your days free to dive and your evenings for fine dining and socializing with shipmates, is pretty close to heaven.


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