Watch 08

One Long, One Short, and What to Do When You Hear It

Where you stand: anywhere within earshot, which on a quiet afternoon covers a surprising amount of the valley. What is wrong with it: modern practice uses radio as well, so silence proves nothing and you cannot rely on hearing anything at all.

The signal

One prolonged blast, then one short blast. That is a vessel asking for a bridge to be opened.

The bridge answers with the same signal, and that means yes, it is opening. A rapid series of short blasts from the bridge means no: something is wrong, or the span cannot be opened at that moment.

That is the whole vocabulary you need, and it is worth learning because it is the only piece of the sequence that reaches you before anything is visible.

What prolonged actually means

Longer than you expect. A prolonged blast is several seconds of sound, not a beep, and at close range it is genuinely loud in the chest rather than merely audible.

The short blast that follows is brief by comparison, and the gap between them is small. Heard from a mile away in the valley it arrives as one long note and one bump, and once you have heard it correctly identified you will never mistake it for anything else.

The practical use, which is the reason for this piece

Sound is how you know where to be.

Everything else in this subject requires you to already be in the right place. A span opening announces itself first by bells at the gates, and by then you need to be standing at the span. A whistle signal arrives earlier, from further away, and it tells you two things at once: that a hull is coming, and roughly from which direction.

So the technique is: stand somewhere in the middle of the arrangement rather than committed to one span, listen, and move when you hear a request. It is the only way to improve your odds without a timetable, and there is no timetable.

What the sequence sounds like, end to end

If you are within earshot of a span and paying attention, the whole opening is audible even if you cannot see it.

1. 1. The request. Prolonged, then short, out on the water.
2. 2. The answer. The same, from the bridge, and closer.
3. 3. Bells. A continuous ringing at the gates, mechanical and unhurried.
4. 4. The gates. Little sound of their own, but the traffic noise changes as the road empties, and that change is the clearest audible cue in the sequence.
5. 5. Lock bars. Two heavy clunks, several seconds apart. The best sound in the subject.
6. 6. The drive. A motor note that starts, settles under load, and holds.
7. 7. The hull. Almost nothing. A large hull moving slowly is remarkably quiet, and the silence at the middle of an opening surprises everybody.
8. 8. Reverse. The motor again, the two clunks in the other order, the bells stopping, and traffic.

Learning that sequence by ear means you can stand somewhere useful with your back to the bridge and know exactly what stage it is at, which sounds like a party trick and is actually how you avoid standing in the wrong place.

Why silence proves nothing

Radio does the same job as a whistle and does not wake anybody within a mile, so a great deal of bridge working happens with no sound signal at all. A span will open in near silence, and if you are relying on whistles you will miss it.

The lesson is not to distrust sound. It is to treat sound as a bonus rather than a system. Use the operator's house as your primary indicator: a light, a movement behind glass, somebody looking down the channel rather than at a desk. Then use the bells, which always happen, because a gate cannot come down without them.

The safety part, which is short and matters

If you are standing on a bridge sidewalk and you hear a prolonged blast begin, that is your cue to be off the movable deck, not your cue to walk out onto it for a better view.

This is the commonest mistake a first time onlooker makes, and it is entirely understandable: the sound is exciting and the deck is where the excitement is going to be. The deck is also the part that is about to become a moving object, and somebody in a room with sight lines down the channel has to notice you and hold everything until you are clear.

Stand on the fixed approach, and the whole question never arises.

A note on what this is not

This is not a guide to whistle signals in general. There is a whole vocabulary of them in use on the water, most of it about vessels talking to other vessels, and none of that is this publication's subject or within its competence.

Two signals, both between a vessel and a bridge, both audible from a public street. That is the scope, and how a lift span works puts them in the sequence they belong to.