Assessing crew risks on a powerboat

Should you require all crew on your boat to wear lifejackets? If so, under what conditions? Should you restrict access to some parts of the vessel when underway? Should those rules change in different weather conditions, or with different kinds of boat traffic nearby?

I suspect that many skippers make these decisions based on gut feeling and on who they side with in bar or forum arguments. Frankly, I don't think that's the best way to make critical safety decisions.

Risk assessment is a very well-developed art. Not every decision calls for a formal risk assessment, but putting a bit of logical thought into your key safety policies is certainly a prudent idea. Today, I present an informal walk-through of this process for the Starwind 860 trimaran we're currently building.

The Boat

Here's the Starwind 860:

From a crew safety standpoint, we can divide this vessel into four distinct zones.

  • The Red Zone includes the foredeck, crossbeams and engine well: areas where it's easy to fall overboard or injure yourself. (On a sailboat, I'd include the bowsprit and the arc of the boom in this zone; on other powerboats, I might pick the swim platform and pulpit.)
  • The Yellow Zone covers the wing decks on the amas (outriggers). There are fewer hazards than in the red zone, but you can still fall overboard or be hit by waves. (On other boats, most regions that are protected by railings or lifelines would fall in this category.)
  • The Green Zone covers the regions where it's very difficult to fall overboard: the boat's cockpit, which is protected by high bulwarks.
  • The Interior includes the boat's small forward cabin, used mainly for storage and for the head.


Let's evaluate the likely risks to a crew member in each zone, and see what we can do about them.

Red zone


These are the least protected parts of the vessel. They're exposed to the full force of wind and waves, and while there are plenty of hand-holds, there is a risk of falling overboard when you're out here. These areas are also far from the boat's pitch centre, so the boat's motion will be at its worst for crew on the foredeck.

On the foredeck, the main risk would be falling. If you were to fall overboard from here, you'd end up under the wing deck, and could hit your head on the way. Foredeck crew would also be handling the anchor or mooring lines, and would have to contend with the associated hazards such as snags and tangles.

At the stern, the motor well contains the engine umbilicals (fuel, electricity, etc.) and the steering linkage. Anyone working back here would have to share the space with all this equipment, without getting caught in it. Obviously, it's not a good place to be when the motor's running.


We can reduce the risks through careful design. Plenty of hand-holds and a non-skid surface are provided in these areas. The anchor and its rode are kept in a locker, and should never have to be spread out on the foredeck.

We can also reduce the risks by setting some rules about what can be done in these regions when the boat is underway. Crew are not permitted in the red zone while the boat is underway, except for anchor handling at dead-idle speeds. Only fit, experienced crew are allowed to handle the anchor, and the anchor handler must wear a PFD.

Yellow Zone


When underway, the wing decks may be empty or they may be used to carry kayaks or other bulky cargo. There is no equipment in this area, so the risk of injury is lower than in the red zone, but someone on the wing deck could fall overboard if the boat lurches or is swept by a wave.

While docking, crew will be on the wing decks with fenders, boat hooks and mooring lines. The boat is heavy enough and powerful enough that grabbing the dock while the boat's moving could result in a broken arm.


Crew are permitted in the yellow zone while underway in calm conditions, but will be ordered back to the cockpit if the skipper decides that weather or traffic conditions warrant it.

Only fit, experienced crew are permitted in the yellow zone while docking. Seniors, kids and known dock-grabbers must stay in the cockpit while docking.

Should PFDs be required in this zone while underway? I am going to say yes for non-swimmers and weak swimmers, and yes for everyone if weather conditions call for it. Anyone who can swim reasonably well is unlikely to fall overboard, and would be easy to recover if he did, on a calm July afternoon. But even a strong swimmer will be quickly incapacitated if he falls overboard fully clothed in the icy water of early May.

Green Zone


It's very hard to fall overboard from here. The major risks to crew in the green zone are of the slip-and-fall variety, but we must also consider the possibility of a collision, a fire, or a very serious storm.

The boat is designed with multiple watertight compartments in all three hulls and all four crossbeams, and would be extremely difficult to sink. While a collision or serious storm would be unpleasant, the boat (or the remains thereof) would likely remain largely intact and mostly floating for a long time. The only scenario likely to force abandonment of the vessel is fire, the risk of which can be greatly reduced by proper systems design.


Engineering controls are built into the design to minimize the chance of being eposed to electrical, fuel or mechanical components, and plentiful hand-holds and non-skid surfaces reduce the chance of slipping on a wet deck.

PFDs are usually unnecessary here, since there is almost no risk of falling overboard and there is a clear delineation (the bulwarks) between the green and yellow zones. In severe weather, though, there is a risk of being tossed about if the boat drops off a wave, in which case PFDs would be a very good idea; we will set the threshold for this at Force 5.



The main risk to crew in the interior, that is not present in the green zone, is the possibility of being trapped by smoke or fire.


Any occupied interior space should always have at least two exits. On the Starwind 860, a large foredeck hatch would provide a nice emergency exit as well as some much-needed ventilation.

PFDs vs. Lifejackets

A lifejacket will keep you afloat and face-up, even if you're unconscious. A PFD (personal flotation device) will keep you afloat, but will not turn you face-up.

Like most small powerboats, the Starwind 860 will carry PFDs for the adults and vest/headpad lifejackets for children. Our experience with lifejackets has been that the foam kind tend to be uncomfortable, so people refuse to wear them- which defeats the purpose. The inflatable kind are more comfortable but very costly. We have found that, if you provide a variety of PFD styles in many sizes, most people can find one they're willing to wear when circumstances require it.

A small, agile powerboat like the Starwind 860 can recover from a man-overboard situation quickly enough that the extra features of a true lifejacket will rarely, if ever, be relevant. On other types of vessels, the opposite may be true- on a sailing monohull, for example, a major cause of man-overboard is being hit in the head by the boom, in which case the MOB could be unconscious in the water for several minutes.


A design that takes crew safety into mind from the start is your first line of defence against injury or man-overboard. Liberal use of hand-holds and flat, non-skid surfaces reduces the risk of falling; damage-tolerant hull design with multiple watertight compartments reduces the risks in a collision; well-engineered and well-maintained systems minimize the chance of fire.

Even so, crew behaviour is a critical factor. So, on the Starwind 860, our crew will be given the following rules:

  • PFDs must be worn in severe weather (more than Force 5).
  • PFDs must be worn when outside the cockpit if the weather's poor, the water's cold, you can't swim well, or any other combination of factors puts you at an increased risk for falling overboard.
  • PFDs must be worn when handling the anchor or any other task that puts you in the red zone.
  • Stay off the foredeck while underway unless your task requires you to be there.
  • Stay in the cockpit while docking unless you're "competent crew".

Even if you don't write it all down, thinking through this exercise for your own boat will make you a better skipper. We've done this for all our boats, and come up with slightly different guidelines for each.

In the 8-foot pedal boat, for example, the lifejacket often stays beside the seat, as this boat is impossible to sink, never goes far from shore, and tops out at three knots.

In the fast runabouts and skiffs, it's PFDs at all times when underway: these boats are fast enough that, in a grounding or collision, you could be thrown from the boat before you realized anything was about to go wrong. In many cases, the analysis need not be any more complicated than that.



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