offshore is unlike diving at a similar depth closer to shore.
In addition to the deep water, you will likely experience strong
currents at the surface and the bottom, especially if the wind
and current are moving in the same direction. Plan your dive around
slack tide for the best underwater and surface conditions.
addition to standard scuba gear, divers should consider
carrying a reel and lift bag to make ascents if separated
from their down line and a safety sausage and whistle or
other surface signaling devices.
completely redundant air supply is also advisable. Since the seafloor
water temperature rarely rises above 50°, drysuits make diving
safer and more comfortable.
Another hazard divers may encounter is fishing gear. Gill nets
in the water column pose the greatest threat to divers because
they are hard to see and are hard to get untangled from. Additionally,
monofilament line, lobster pot lines, and trawl nets can also
ensnare divers. Be particularly aware of your surroundings if
you are close to boats actively fishing since they might not be
aware of divers under the water. It would be wise to carry a second
knife or cutting device so you can free yourself if you become
entangled and cannot reach your primary cutting tool.
It is essential that your dive boat flies a red and white diver
down flag and the blue and white international dive flag since
the sanctuary is frequently transited by both American and foreign
flagged ships. Also be aware that portions of the sanctuary are
located in the shipping lanes for vessel coming into or out of
the port of Boston.