A wooden box, full of engine.

First · A sense of scale

How big is she, really?

Everything below is a number about a very small boat, and “fourteen feet” doesn’t mean anything until you stand it next to something. So here she is on one line with a school bus, a blue whale and the kind of working tug she is doing an impression of. Everything is drawn to the same scale; the figure beside each one is a six-foot adult. Drag the harbor.

A blue whale is about 5.8 AWOOGAs nose to tail. The school bus that goes past her driveway is nearly 2.8. The harbor tug she was designed to look like — the one whose job she is pretending to do — is 6.3 of her, and sits well over a dozen feet deeper in the water.

Look up rather than along, though, and the strip gives away something better. With her mast up she stands nearly twelve feet out of the water — taller than the school bus parked beside her, on a hull short enough to fit inside that bus nearly three times over. The mast folds flat on a lever, which is the whole reason she gets under a bridge. Keep the proportions in your head for everything that follows: all three of the ideas below are the same physics the big tug runs on, worked out at one-sixth the length.

Part one · Buoyancy

She doesn’t float because she’s light

Two thousand years ago Archimedes worked out the only rule that matters here: a floating thing pushes aside exactly its own weight in water. Not its own volume — its own weight. AWOOGA weighs whatever she weighs, and she settles down into the harbor until she has shoved that many pounds of Long Island Sound out of the way. Then she stops. That’s floating.

Which leads to the fun part. Put something heavy aboard and she has to shove aside more water, so down she goes — but only far enough to displace the new weight. And because she is a wide, flat-bottomed boat, that turns out to be almost nothing. Load her up:

Part two · Speed

Why 20 horsepower is plenty

A boat like AWOOGA doesn’t skim over the water — she pushes through it, shouldering a hole in the sea and dragging it along behind her. And a hole in the water has a top speed. As she goes faster, her bow wave gets longer, until the wave is as long as the boat and she is effectively trying to climb up her own hill. That’s hull speed, and no amount of engine gets you meaningfully past it.

It depends on one measurement: how long she is at the waterline. Not her overall length — the bit actually in the water.

Part three · Shape

Tugs are not built to go fast. They’re built to push.

Everything a tug does happens at almost no speed at all: leaning on the side of a ship, holding a barge against a current, dragging something enormous away from a pier at walking pace. The number that matters isn’t top speed, it’s bollard pull — how hard she can haul while standing still.

That’s a shape problem, not a horsepower problem. Push sideways on something and it wants to roll over; the cure is beam. A wide hull resists the heel, keeps the propeller buried, and gives the crew a deck that stays flat while all that force goes through it. So tugs are fat. AWOOGA is very fat.

Every hull above is drawn to the same length so you can compare their beam directly — a racing shell laid alongside AWOOGA at true scale would be four times as long as this page is wide. Ratios for the other boats are typical of their type. (For sizes at true scale, drag the strip at the top of the page.)

At 2 : 1, AWOOGA is proportionally beamier than the working tugs she imitates. Seven feet of boat across fourteen feet of boat. She is, geometrically speaking, almost a square — and that is exactly why seven adults can stand up in her and nothing interesting happens.