Plastimo Compasses

Navigation Instruments and Compasses

How to select your compass


Plastimo owes its position as market leader not only to their extensive range compasses, but also to the continuous R&D effort needed to offer such a top quality product.


Selecting the best compass for your boat is extremely important, as the compass will be the the helmsman's navigation mate for many years. Your selection should be made taking into consideration.

Your type of boat: dinghy, cruising boat, racing boat, power boat... Features may include a removable compass on a fixed bracket, a fully gimballed unit, a tactical card, or a spring loaded suspension (for power boats).

Your type of navigation: day sailing, cruising, long shore navigation... You may select a small or larger compass with or without lighting, with or without compensation, with the right balanced card for the geographical area where you are going to sail.

The location of the compass on the boat: bulkhead mounted, flush mounted on the deck or on the dash board, mounted on a steering pedestal, on a mast bracket... you will choose a compass which is easily readable. Often located at the heart of your boat, your compass should ideally match and enhance the character of your boat . you will therefore pay particular attention to its design and colour.

Some Helpful Hints

How to establish a deviation curve with a handbearing compass

Plastimo suggests an extremely quick and easy method which consists of comparing the information given by the steering compass in different directions with those of the handbearing compass which would be used in an area free of magnetic disturbance.

Finding the ideal location on board

Firstly, a seamark should be picked out. This will serve as the point of reference. This point should be at least 3 miles from the boat and the sea should be calm. Locate an area on board that in principle is not subject to magnetic disturbance. The rear of the boat is usually a convenient location. Then, whilst pinpointing the seamark with the handbearing compass, turn the boat slowly round in a circle about 4 to 5 times the length of the boat. If the bearings remain constant, this means that the location you have chosen is free from magnetic disturbance If this is not the case, find another location on the boat.

Checking the accuracy of your ship's steering compass

Turn the boat round in different directions and compare the course readings of the steering compass with the handbearing compass which should be positioned along the longitudinal axis of the boat. Any difference is due only to the deviation of the steering compass.

Establishing the deviation curve

In the event of deviation, turn the boat in various directions (N, 22o, 45o, 68o, E, etc.) and note the differences. Then trace out the deviation curve of the steering compass. If the steering compass has a higher course than the handbearing compass this means that the deviation is west and vice versa.

Compensation of your ship's steering compass

If the deviation is more than 10o, your ship's steering compass must be checked for compensation. If this is the case, refer to the steering compass instruction manual.