Flybridge and Upper-Deck Safety: Weight Up High, Rails, Ladders and CO

Read the owner's manual and look for labels at the flybridge ladder, hardtop, tower or upper deck. Some builders give a maximum number of people or pounds for the flybridge or upper deck; some boats built to European (CE) rules carry a passenger capacity by design category. If you find nothing, call the builder or ask a marine surveyor. Write the number on a small sign at the bottom of the ladder.

Without a builder figure, be conservative. Use Gerr's example as a gut check: on a mid-30-foot cruiser, two or three people on the bridge, not eight. BoatUS technical editor Tom Neale adds that four or five people on the flybridge with nobody below can capsize even a 35-foot boat, so have guests take turns up top and keep the number small enough that the boat doesn't lean as they move around. His rough rule for boats without a plate, used with caution: count only the fixed seats in the main cockpit, not the bow or flybridge seats. Keep the heaviest people and coolers on the main deck, low and near the centerline. On a pontoon with an upper deck or slide, treat everyone up top as a big shift in balance, not just added weight, and keep within the boat's capacity plate if it has one (see weight distribution and loading).

Fireworks, raft-ups, boat parades and inlets mean lots of boats, big crossing wakes and people who all move to one side to look. Before heading out in these conditions, bring people down from the bridge, slow down, and take big wakes at an angle rather than on the beam. The owner in the 2012 accident blamed a large wake; experts pointed to the overload. Either way, the two together are what roll boats.

Once a season and after any hard hit:

• Push and pull every rail and stanchion. Any movement, cracks in the gelcoat around the base or rust weeping from fasteners means it needs rebedding or repair.
• Check that rail fittings and set screws are tight and not cracked.
• Make sure any gate at the top of the ladder latches firmly and can't swing open if someone falls against it.
• Look for missing or broken lifelines or canvas side curtains that people might lean on as if they were rails. Canvas and clear enclosures are not barriers.
• Know what "high enough" looks like. BoatTEST quotes the ABYC standard for flybridges: the outer edge should have a rail, coaming or enclosure about 30 inches above the deck, or seatbacks at least 24 inches high, which is about 6 inches more than the standard asks of main-deck rails. If a builder relies on seatbacks as the barrier, don't let people sit on the seatbacks or stand on the seats, and keep small kids from climbing them; a person perched on top has no barrier at all. If a section of your bridge looks lower than that, or a rail was removed for a new enclosure or electronics, ask a surveyor before carrying guests up top.

Check treads for wear and slipperiness, and add non-skid where it's worn. Make sure the ladder is tight at top and bottom, handrails are solid all the way down, and nothing is stored on the steps. Fix a loose ladder before the next trip: it's a fall waiting to happen.

• Bring guests down before conditions get rough, not in the middle of it.
• Slow down and, if you can, put the bow into the seas while someone climbs.
• Face the ladder, keep three points of contact (two hands and a foot, or two feet and a hand), and don't carry things: hand bags and drinks down separately.
• One person on the ladder at a time.
• Kids and anyone unsteady wear life jackets on the flybridge and come down with an adult below them.

Hardtops, radar arches and fishing towers are built for their own weight, the gear the builder planned for, and wind. They are not decks unless the builder says so. Don't let people sit or stand on a hardtop or arch, and don't add heavy electronics, kayaks, paddleboards or extra speakers up there without checking the builder's rating. Weight high up hurts stability the same way people do, and it loads the mounting bolts (see tower hardware check).

The Coast Guard lists the ways carbon monoxide builds up around boats, including exhaust trapped by canvas enclosures and the "station wagon effect" (back drafting), where a low-pressure area behind a moving boat pulls exhaust forward into the cockpit. It's worst at slow speed, idling or stopped, and CO can stay at dangerous levels after the engines shut off, including from a neighboring boat's engine or generator. On flybridge boats, a fully enclosed aft deck or bridge with canvas can trap fumes.

• Install marine CO alarms in the cabin and enclosed areas and test them before each trip (see CO detector safety).
• Open forward hatches or front canvas panels when running with the rear enclosure up, so air flows through.
• Nobody on the swim platform or in the water at the stern while engines or the generator run.
• Don't idle for long with the stern into the wind, and watch for boats rafted next to you running a generator.

Steering from the bridge, you can't see people on the swim platform or right below the bow. Before starting engines or shifting into gear, have someone confirm the swim platform and water at the stern are clear, and keep the engine cut-off lanyard or wireless fob on whoever is driving.

The higher you sit, the more every wave swings you around. In a Mercury Dockline piece, TV fishing host Peter Miller describes his own rules for the upper helm (tower) of his center console: run well below the boat's top speed, usually allow only one other person up there so the driver has room to brace and keep a firm grip, and drive from the lower helm once the seas reach about 3 feet. The same thinking applies to a flybridge: slow down and come down when it gets rough.

In one minute: how many people are allowed up top, hold the rail on the ladder, nobody sits on rails or the hardtop, come down when the skipper says so, and where the life jackets are.