Lesson 8
Boating Diving Safety basics
Learning Objective
By the end of this topic, you should be able to answer these question:
Piloting
Words like “piloting,” “navigating,” “steering” and so on tend to get used interchangeably, and most of the time, what we mean is clear. However, sometimes these terms have very specific meanings for a particular way of operating a vessel. In this respect, piloting means to use landmarks, aids to navigation and soundings to guide a boat safely through channels, harbors and along coasts where dangers to navigation require your constant attention to position and course. In other words, it’s finding your way based on what you see around the boat. This separates piloting from open ocean operations during which a captain may use GPS and compass headings for navigation.
All vessels must be piloted at various times. In some areas, virtually all boat operation takes place based on piloting, whereas other vessels (particularly transoceanic ships) only use piloting for approaching and leaving port.
Piloting has seven dimensions:
1. Direction – the position of one point relative to another, usually between where you are and another point, or between two known points when you’re navigating.
2. Distance – the space between two points, which the pilot may judge based on linear measurement (metres/feet/nautical miles) or based on time, i.e., how long it takes to get from one point to another at a given speed.
3. Time – A pilot doesn’t need as accurate timekeeping as does, say, a celestial navigator, but the ability to roughly determine time is important in piloting.
4. Speed – how fast the vessel’s going, as well as estimates of other vessels.
5. Position – A pilot must constantly be aware of the boat’s position.
6. Depth – measured either directly with a depth finder (fathometer), or indirectly based on the boat’s position compared to experience with the local waters, charts, and channel markings.
7. Height – primarily a concern for sailing vessels, but applies to any vessel with a mast that must pass under a bridge or other low obstacles.
Dead Reckoning (DR)
Before the invention of GPS, the primary means of navigation when well beyond sight of land was dead reckoning. Dead reckoning is determining the boat’s position based on estimated changes from its last determined position by tracking the courses steered and speeds. In other words, it’s a highly educated (and with experience, surprisingly accurate) guess.
With the rise of GPS, dead reckoning isn’t nearly as common as it once was, but it’s still taught as a means of navigating in the case GPS and other means of navigation should fail. And, like many esoteric skills, some captains carry it on because they enjoy the challenge and skill it requires, and they don’t want to see it become a lost art.
To dead reckon, the captain needs to track the vessel’s course, the heading (which isn’t always the same as the course due to wind and current), speed and distance – the intended future path for the boat. The track always starts from a known position. Then, the captain or navigator plots the boat’s course estimate on a chart, updating it frequently based upon changes in heading, speed or other variables. The course is updated and dead reckoning restarts upon reaching a known navigation point, such as a recognizable landmark. As you may imagine, prior to modern electronic navigation, the captain navigated by combining dead reckoning with piloting and, when the sky was clear, celestial navigation (use of the stars and sun to determine position).
Mooring and Anchoring
The vast majority of boat diving takes place with the vessel moored or anchored over or near the dive site. To those who watch the process, it looks deceptively simple. Tie up to a mooring ball or throw an anchor over the side and let out some line – what more could there be to it? The answer is, “more than you might imagine.”
Although you probably know this, for clarity let’s define mooring and anchoring.
Mooring means you secure the boat over a site by tying to a permanently placed anchor system called (not surprisingly) a mooring. With a mooring, a buoyed line to the bottom remains permanently in place, and the boat ties to the line.
Anchoring means you secure the boat over a site by dropping anchor.
Of the two systems, moorings are preferred and have become common at dive sites at popular dive destinations. However, in areas where environmental or management consideration limit the use of moorings, responsible anchoring is a prevailing practice.
Moorings make it easier to find the dive site, to secure the boat and to reduce environmental damage. Anchors are still commonly used by dive boats in places with resilient environments that can withstand anchoring without a significant environmental effect. In many of these places, the environment is such that moorings aren’t practical because storms and high seas destroy them.
Whether mooring or anchoring, the captain has four considerations when securing the boat for diving:
Mooring Setup and Mooring
Mooring is simpler and quicker than anchoring, it still has considerations and procedures. The vessel must be equipped for mooring prior to setting out, and different mooring systems have varying requirements. We’ll look at a common mooring system setup and its procedures, but it’s important to be familiar with the specifics of a mooring you plan to use.
For “typical” moorings, the crew prepares a short line (3-5 metres/10-15 feet) with a quick shackle on the free end. The line routes through the anchor tackle and secures on the anchor cleat with a cleat hitch. There is a boat hook stored on the bow, or place where someone can pass it easily to a crewmember on the bow.
As with anchoring, the captain ensures the area is clear of divers and boats while approaching and motoring gently toward the mooring buoy. Using the boat hook, someone on the bow pulls aboard the line trailing from the buoy, passing it under the rail.
The crew member snaps and secures the shackle to the eye in the trailing line, ensuring that when the line’s released, it will put tension only on the anchor tackle and cleat.
After securing the line, the end is cast off while the captain puts the engine in neutral, allowing the boat to drift back to confirm its holding before shutting down. Moorings are well secured and have adequate line or scope coming up, so there’s no need for additional scope.
The short scope is an advantage for you during the dive because you reach the bottom faster following it down.
The drawback compared to anchor line is that when mooring lines are not changed frequently, they are quickly overgrown by a variety of organisms, so you may have to wear gloves and watch where you put your hands. However, if you dive in an area where wearing gloves is prohibited, take off your gloves as soon as you clear the line and secure them in your BCD pocket until you need them for ascent.
Releasing from a Mooring
After all divers are aboard and accounted for, the captain makes sure the area is clear of boats, divers, etc. and starts the engine. The captain motors gently toward the mooring while the crew pulls in line, releases the shackle, and casts loose. The captain allows the boat to drift away from the mooring buoy before engaging the engine to avoid accidentally entangling the line in the propeller.
Note: In many dive destinations, particularly those with fragile reefs and/or vulnerable shipwrecks, mooring systems are increasingly becoming the rule.
Anchoring Setup and Anchoring
Anchoring begins long before you leave the dock by having your anchor set up and ready. That means having the correct type of anchor for the bottom you’ll be placing it in, such as a Danforth® anchor for sand or a grappling hook for rocky bottoms. The lower portion (usually 3-6 metres/10-20 feet) of the anchor line is chain to resist abrasion and to aid the anchor’s grip. The anchor line and chain feed off the bow from the anchoring tackle, with the line stowed in the chain locker so it deploys without resistance when you drop anchor.
To anchor, the captain motors over the anchor spot and heads into wind so the anchor is less likely to disturb the bottom (found via piloting, GPS and the fishfinder). After checking that the area is clear of divers, boats, sensitive organisms or cultural artifacts, the captain maintains the boat in position while the anchor is released so it drops to the bottom. When it makes contact, the captain puts the boat in neutral and allows it to drift back while paying out anchor line.
The amount of line released depends upon the bottom type, the boat and anchor sizes and the wind/current pushing the boat. The more line or scope, the better the anchor holds all else being equal. For short-term anchorages in calm conditions, the recommendation is that the scope should be at least three times the depth, For longer stays or depending on the situation, the crew may use more scope.
With sufficient scope released, the crew ties off the anchor line on the anchor cleat. The captain makes sure that the anchor is secure (not dragging) before shutting down the engine. Someone should check periodically to be sure the anchor continues to hold.
Ensure that the anchor line has a quick release shackle and buoy attached so you can jettison the anchor in an emergency without having to retrieve it from the bottom.
Note: In some areas with sensitive aquatic life or vulnerable cultural artifacts, it is illegal to anchor except in a life-threatening emergency. Such areas will have moorings if diving is permitted.om.
Weighing Anchor (anchor retrieval)
When it’s time to go, the captain and crew confirm that all divers are aboard and the area around the boat is clear of hazards such as other boats and their divers. The captain starts the engine and motors toward the anchor while taking up and stowing anchor line. When nearly directly over the anchor, the anchor will no longer hold well and be easy to pull from the bottom.
If the boat is a small boat with a small anchor, one or two people simply haul the anchor up, hand over hand. Large boats (such as the typical dive charter boat) use the anchor winch to raise the anchor. To minimize damage to the environment, the captain motors in place until the anchor comes well clear of the bottom.
Basic Guides to Boating Safety
As with dive safety, boat safety is more a matter of attending to many small things than one big thing. In the excitement of heading out on a boat dive, if you’re on a private vessel, it’s possible to overlook something that prevents boat emergencies or allows you to respond to emergencies effectively.
Just as you learned to perform a predive safety check to make sure you’re not overlooking the basics, boaters run through a quick pre-departure checklist and to abide by the following basic guides to boating safety. The captain and crew are responsible for most of the following guides when you dive from a charter boat. When you dive from your own vessel, these are your responsibilities.
Batteries, Power, and Charging on Dive Boats
There are important safety recommendations for charging lithium-ion batteries and using power strips and extension cords on boats due to increased fire risk. A large number of rechargeable electronics, combined with the limited circuit capacity of many vessels and the abundance of flammable materials, makes onboard electronics use, and battery charging in particular, an increasing fire concern.
Follow these procedures to help prevent and be prepared for an onboard fire:
In Case of Emergency
Fortunately, boat accidents are rare. However, should you be involved in an incident on a vessel when an injury requiring medical treatment, the disappearance of someone, significant property damage or a fatality occurs, an incident report must be filed with responsible law enforcement agencies in most areas. This is normally the responsibility of the captain and/or vessel owner.
In the event of an incident, all vessels involved are required to stop and provide assistance to other persons as needed regardless of which vessel they’re on, provided doing so doesn’t endanger a boat providing aid, passengers or crew.
In some countries, all vessels – involved in the incident or not – are required to provide assistance if they can do so without endangering themselves. Failure to provide aid when legally required to do so can carry stiff penalties. (Fortunately, most boaters and divers would do this anyway.)
Sometimes local authorities request vessels in the area to assist. If you’re captaining a private vessel or aboard a chartered vessel that is assisting others, be prepared to help, but don’t take unnecessary risks. This is like the PADI Rescue Diver philosophy that to be able to help, you have to keep yourself out of trouble first.
If your vessel is involved in an accident that includes damage to the fragile natural or cultural resources (such as groundings or spills), you should also contact local authorities, in particular when operating in environmentally sensitive areas such as marine parks and other protected sites. It is particularly important that you minimize the extent of damage already done and do not try to power off the damaged area. Instead, communicate with the authorities and wait for help.
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