1. How a pilot boat travels from land to the big ship at sea
A pilot boat is a vessel that takes the harbor pilot to and from the ship they are guiding [1]. The pilot starts at a base on land, boards the pilot boat, and travels out to the large ship waiting in the open water [2]. For example, in the Inland Sea pilotage area, there is a specific spot off Wadamisaki where pilots board and leave ships [8].
It is surprising that the large ship is not always stopped. According to the Japan Federation of Pilots, pilots often board and disembark while the main ship is underway (moving) [3]. The word "often" means it does not happen every time. However, it is common for a small boat to approach a moving ship. When the ship is moving, wind and waves affect the small boat's movement. So, which side of the ship does the boat approach? Is there a rule?
2. Why the pilot boat approaches the leeward (downwind) side of the ship
The Japan Federation of Pilots states that when there are wind and waves, pilots board and leave on the leeward side of the ship [3]. The leeward side is the side the wind is blowing towards. Because wind can come from the right or the left on different days, the side that is easier for the pilot boat to approach changes. Therefore, large ships are required to have boarding equipment on both sides [3]. This means the large ship prepares for the small boat, rather than the other way around.
This information comes from a guide by the Japan Federation of Pilots, which includes translations of International Maritime Organization (IMO) standards [3]. Next, let us look at the rules for the height of the ladder.
3. Why a pilot ladder is used for heights between 1.5m and 9m
The ladder the pilot climbs is called a pilot ladder [2]. International standards say that climbing via a pilot ladder is used for heights between 1.5m and 9m above the sea surface [3]. If the boarding point is higher than 9m, ships use an accommodation ladder (a gangway) along with the pilot ladder. If it is lower than 1.5m, pilots board directly without a ladder [3].
How high is 9m? 1.5m is about the height of a primary school student. 9m is six times that height. It is the vertical distance from the water to the entry point, not just the length of the ladder. To a pilot, the side of a large ship looks like the wall of a building.
There are rules for how the accommodation ladder is placed. The bottom platform must face towards the stern (back) of the ship. If it faces the bow (front), the pilot boat moving alongside could slip under the ladder, which is dangerous [3].
Safety Note: The bottom platform must face the stern. If it faces the bow, a pilot boat next to a moving ship could get trapped under the ladder, which is very dangerous [3].
4. Why the ship's side needs a gap for the pilot boat
IMO standards have a section called "Safe access for pilot boats." If things like fenders (bumpers) on the side of the ship might block the pilot boat, there must be a clear gap at least 6m wide [3]. Fenders are protrusions on the side of the ship to protect it from hitting docks or other ships. If they get in the way, a space is cleared for the pilot boat. There are exceptions, including for some ships under 90m [3].
Approaching a large ship is not just the small boat's job. The large ship also prepares to receive the pilot boat according to these rules.
Safety Note: IMO standards state that if fenders or special structures block safe access, a gap of at least 6m width must be provided [3]. This shows that pilot boat safety depends on the design of the large ship, not just the pilot boat's performance.
5. How pilot boats changed from small sailing vessels to fast motorboats
The ancestors of pilot boats were small sailing vessels. In the past, pilots used their own fishing boats to meet large ships. Later, they became specialized "pilot cutters" [5].
A clear example of this change happened in the United States. The schooner "Roseway," owned by the Boston Pilots, was retired in 1973. It is said to be the last sailing pilot schooner [4]. It marked a turning point in the US example.
Meanwhile, motor pilot boats got faster. In 1957, the "Brandywine" had an old design and a speed of about 10 knots. In 1979, the "Delaware" was built with a deep-V hull from bow to stern, suggested by Delaware pilots. It could reach about 20 knots [4]. One knot is about 1.85 km/h. So, 10 knots is about 18 km/h, and 20 knots is about 37 km/h. The speed doubled. This is a US example. Japanese pilot boats did not necessarily change in the same way at the same time. However, speed helps catch up to and approach a moving ship.
6. What pilot boats look like today and how to spot them by the word "PILOT" and the H flag
Today, pilot boats vary in size and shape by country and port. They can be single-hulled, twin-hulled (catamarans), or have wave-piercing shapes. Because they often touch huge steel ships, they are built to be very strong [6].
To spot one, look for a brightly colored boat with "PILOT" written large on the side. A common international example is a boat painted orange, red, or yellow, flying an H flag. The H flag is half red on the left and half white on the right. It means "A pilot is on board" [5]. Ships that need a pilot fly a G flag [7]. These are general examples. Japanese pilot boats may not all look exactly like this.
7. How to feel the 1.5m to 9m ladder height at home with a string or tape measure
Measure 1.5m with a string or tape measure and hold it against a wall. Connect six of these to make 9m. If you spread them out in a hallway or park, you can feel how high the maximum boarding height is. 9m is about the height of a building’s third floor.
If you visit the sea, look for a small boat running near a large ship. It might be a pilot boat. Look for the "PILOT" text, the H flag, and bright colors. Even if you do not see one, these boats work in ports where ships enter and leave. Be careful of wind and waves at the coast. Do not go near the water's edge.
English sources say that for very large ships, pilots sometimes board by helicopter instead of using a ladder [5]. There are different ways to board besides climbing 9m.
Safety Note: Spreading out the string in a safe outdoor place helps you understand how high a building's third floor is.