SOUND SIGNALS

Just as lights play a significant role in understanding what other boats are doing, so do sounds.  Understanding what you hear is another step towards being a "complete mariner".  Virtually every boat is required to have some sound producing device.  There is a great deal of latitude in what type of sound making device you choose, but loud is good!

Legal Requirements

Equipment for Sound Signals is based on the length of your boat as follows:

• Boats less than 39.4 feet in length - must carry an efficient sound producing device. In general, this may be a bell, whistle, or air horn.  Though guns--even pots and pans--can make a suitable sound signal useful in getting attention in an emergency, you should always carry the appropriate equipment.
• Boats at least 39.4 feet to less than 65.6 feet in length - Must carry a whistle and a bell. The whistle must be audible for 1/2 nautical mile. The mouth of the bell must be at least 7.87 inches in diameter.

WHEN AND HOW TO SOUND OFF

Sound signals are to be used only when vessels are in sight of each other and are meeting or crossing at a distance within half a mile of each other. These signals must never be used in fog or other conditions of reduced visibility, where the vessels are not visible to each other by eye. Only the fog signals listed under the Inland Rules, Rule 35 may be sounded at such time.

SIGNALS

Sound signals are called "blasts".  There are two different blasts used for warning and steering signals.

• Short Blast - Lasts about one second.
• Prolonged Blast - Lasts from four to six seconds.

MANEUVERING SIGNALS

There are different blasts combinations for various movements on the water that may use both short and prolonged blasts. When power-driven vessels are in sight of one another and meeting or crossing at a distance within half a mile of each other, each vessel underway, when maneuvering as authorized or required by the Inland rules must use the following sound signals:

Note:  Inland Rules regarding sound signals are occasionally different from International Rules.  Inland Rules signal intended action and International Rules signal what you are actually doing.  The following information reflects Inland Rules.  If you travel overseas, you must learn the International Rules.

• ONE SHORT BLAST - This means that you "intend to leave you on my port side"  if you are meeting or crossing another vessel.   In other words, when you pass the other boat, the left side of your boat will be next to the other boat.  If you are behind another boat and about to pass it, one short blast means that you "intend to pass on your starboard side".
• TWO SHORT BLASTS -This means that you "intend to leave you on my starboard side in a meeting or crossing situation."  In other words, when you pass the other boat, the right side of your boat will be next to the other boat. If you are behind another boat and about to pass it, two short blasts means that you "Intend to overtake on your port side."
• THREE SHORT BLASTS - This means that you are backing up, or using "astern propulsion".
• ONE PROLONGED BLAST - Signals that you intend to leave your dock.  If you need to back out of your docking area, you would sound one long blast, and then three short blasts.
• FIVE SHORT BLASTS - This is the DANGER signal.  Remember, that When you approach another vessel and hear either one or two short blasts, and you both understand their signal and can safely let them do it, then you are required to respond with the same signal in response.  However, if you don't understand their intentions, or feel that their proposed maneuver is dangerous to either vessel, then you are required to sound the DANGER signal.

NOTE:  Another option is to use your VHF radio to reach agreement with another vessel in a meeting or crossing situation. The Rules state that vessels that reach agreement over VHF radio do not need to make the required sound signals.

 

Power Driven Boats Crossing Port to Port
	Click Here for Animation                Click Here for Description

 

Power Driven Boats Crossing Starboard to Starboard
	Click Here for Animation                Click Here for Description

 

Power Driven Boats Passing to Port
	Click Here for Animation                Click Here for Description

 

Power Driven Boats Passing to Starboard
	Click Here for Animation                Click Here for Description

 

Power Driven Boat Leaving the Dock
	Click Here for Animation                Click Here for Description

 

Danger Signal
	Click Here for Animation                Click Here for Description

 

 

 

 

OTHER SOUND SIGNALS

Reduced Visibility: Power Driven Vessels making way through water - one prolonged blast sounded at two-minute intervals. Underway but stopped and making no way through the water : Two prolonged blasts in succession with two second intervals between blasts sounded at two-minute intervals.

Sailboats or vessels not under command, restricted in ability to maneuver, towing or pushing another vessel, or engaged in fishing with nets or trawling: One prolonged followed by two short blasts sounded at two-minute intervals.

Vessels at anchor:  A vessel at anchor shall at intervals of not more than one minute ring the bell rapidly for about five seconds.   Vessels over 100 feet must ring a bell in the forepart of the vessel, and immediately afterwards in the after part of the vessel.  Boats less than 12 meters (less than 40 feet) must make an efficient sound with an interval of no more than two minutes.  If you see a vessel approaching, you may also sound the following signal: one short, one prolonged, and one short blast in quick succession.

 

Approaching a Bend or Channel Obstruction
	Click Here for Animation                Click Here for Description

 

These are not the only rules concerning sound signals in restricted visibility; there are additional rules concerning sound signals that may be found in the Rules of the Road or in Chapman's Piloting.