Just as lights pat a far-ranging role in understanding what other boats are doing, so perform sounds. Expertise what you hear is another step towards being a "complete mariner". Practically every boat is required to have some sound developing device. Over there is a great deal of latitude in what form of sound making maker you choose, yet loud is good!

Legal Requirements

Equipment for Sound signals is based on the size of your boat as follows.

You are watching: 3 long 2 short ship horn

Boats much less than 39.4 feet in size - must lug an efficient sound creating device. In general, this might be a bell, whistle, or wait horn. Despite guns--even pots and pans--can make a perfect sound signal useful in obtaining attention in an emergency, girlfriend should constantly carry the ideal equipment. Boats at the very least 39.4 feet to much less than 65.6 feet in length - Must carry a whistle and a bell. The whistle should be audible because that 1/2 nautical mile. The mouth of the bell have to be at least 7.87 inch in diameter. When and How come Sound off

Sound signals space to be provided only when vessels room in sight of each other and also are conference or cross at a street within half a mile of each other. These signals have to never be used in fog or other conditions of lessened visibility, wherein the vessels room not clearly shows to each various other by eye. Only the fog signals detailed under the Inland Rules, preeminence 35 may be sound at such time.


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

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

Maneuvering Signals

There are various blasts combinations for assorted movements ~ above the water that might use both brief and an extensive blasts. When power-driven vessels are in vision of one another and meeting or cross at a street within fifty percent a mile of every other, each vessel underway, when maneuvering together authorized or required by the Inland rules need to use the adhering to sound signals.

One brief Blast - This method "I intend to leave you top top MY port side". When you happen near another boat, you will certainly manuever by leaving lock on your left side together you pass. If you are behind an additional boat, walk the exact same direction and around to overtake it, one brief blast means: "I intend to happen you on her starboard side, MY port side". One an extensive Blast - This way you space leaving a dock or departing her slip. It signals to others a adjust in status and also that you are gaining underway. A prolonged blast is likewise sounded as soon as a courage is approaching a bending in a river wherein vessels coming from an additional direction cannot be seen. The is periodically referred to as the “blind bending signal". Two short Blasts - This way "I intend to leave you on my starboard side". Once you happen near another boat, you will certainly manuever through leaving castle on your right side as you pass. If you space behind one more boat, walking the exact same direction and about to overtake it, two brief blasts means: "I intended to happen you on her port side, mine starboard side." Three brief Blasts - This method you room operating in astern propulsion, for example backing far from a dock One prolonged Blast + Three quick Blasts – This is technically two different signals in succession. One an extensive blast indicates you are obtaining under way, and three quick blasts show you space backing up. This is what is sounded once you room departing a dock in reverse. Five quick Blasts - This is the risk signal. Remember, that once you approach an additional vessel and also hear either one or two short blasts, and you both recognize their signal and can safely allow them execute it, then you are forced to respond v the exact same signal in response. However, if you don"t understand their intentions, or feel the their proposed exercise is attention to one of two people vessel, climate you are compelled to sound the danger signal.

Note: Inland Rules concerning sound signals space occasionally various from international Rules. Inland rules signal intended action and worldwide Rules signal what you space actually doing. The complying with information reflects Inland Rules. If you take trip overseas, friend must discover the global Rules.

Proper Sound Signals

Passing harbor to port

When you satisfy an oncoming vessel, and also wish to pass port come port, girlfriend are required to sound one quick blast v your horn. If the other boat is in agreement, they must respond through a comparable blast.

happen Starboard to Starboard

If you approach an additional vessel head on, and wish to happen it on its starboard side, friend are forced to sound two short blasts with your horn. If the other vessel is in agreement, they must sound the same signal in response.

overcome on Portside

When you are planning ~ above passing one more vessel indigenous behind, there are numerous things you must do. Any vessel the is overtaking an additional must store out the the method of the vessel being overtaken. This way that you can"t mean them come move, slow down, or readjust their course. If you setup on passing lock on your starboard side, you must sound one quick blast. If they understand your signal and agree, they will sound one quick blast in response. The vessel being overtaken has actually a obligation to preserve course and also speed in bespeak to minimize the potential because that collision.

overtaking on Starboard

When you are planning on passing an additional vessel native behind, over there are number of things you must do. Any type of vessel that is overtaking another must store out of the method of the vessel gift overtaken. This way that you can"t expect them come move, sluggish down, or readjust their course. If you setup on passing lock on THEIR harbor side, you should sound two quick blasts. If they recognize your signal and agree, they will certainly sound two quick blasts in response. The vessel gift overtaken has a duty to maintain course and speed in stimulate to minimize the potential for collision.

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Note: These space not the just rules worrying sound signals in minimal visibility; over there are additional rules worrying sound signals that may be found in the rules of the road or in Chapman"s Piloting.