What is Monkey Island on Ships?

The term “monkey island” refers to a place on the ship which is located at the top most accessible height. Technically, it is a deck located directly above the navigating bridge of the ship. It is also referred to as the flying bridge on top of a pilothouse or chart house, and also as the ship’s upper bridge. Sailors would use this place to perform solar and stellar observations.

During the ancient time, when ship used to have masts and sails, the monkey island was also supposed to be located about 3/4th way up the main mast on few ships.

There is no solid evidence or proof to back the origin of the term “monkey island”; however, there are a few theories that believed to be the reason behind the usage.

According to this theory, it is believed that in the ancient days, cannon balls were stored aboard ships in a brass frame or trays called “monkey”. During extreme cold climatic condition, the brass trays would contract and spill the cannon balls.

Hence, a humorous reference was established that the climate was cold enough to freeze the balls of a brass monkey. However, this theory is hardly believed to be true because of a number of reasons:

There is no evidence found that such “deck” place on the ship was named as a “monkey”

The rate of contraction of the brass frame cannot so fast as to cause the mentioned effect

According to the past records, cannon balls were not stored on the deck except during a battle. The deck was kept as clear as possible

Practically it is not possible to store cannon balls at such height as during heavy rolling and pitching, the cannon balls would fall off causing harm to the ship and its crew

Though there is no concrete theory to back the origin of Monkey Island, the term is still extensively used even on modern ships.

In modern day merchant ships, the monkey island isn’t just a space to take celestial observations but an integral part of the ship where most of the external parts of the equipments of the bridge are housed. While the navigation bridge houses the display interfaces of most the bridge equipments for use buy the OOW, the monkey island is where the ‘powerhouse’ of each of those equipments are placed. Some of these driving units that are placed on the monkey island are:

VDR capsule

AIS Tx/Rx antennae

Radar scanner(s) attached to the radar mast

Sat C/F77 Tx/Rx antennae

Communication equipment gear

Various halyards connected to the yardarm to hoist flags

Weather vane

The mast leading up to the ‘Christmas Tree’ (navigation lights)

The mast leading up to the ship’s aft whistle