Binnacle Mount Marine Compass

4''(120mm) Diameter Capsule

Durable plastic housing and detachable sunshade with built-in compensators and lighting system.

Net weight 2lb 7oz (1,100 gr)

7.25" (185mm) Overall height
8" (295) Overall width
5.75" (145mm) Body diameter

Economy option suitable for powerboats and multi-hulls.

Below is illustrated the FULL INTERNAL GIMBAL SYSTEM showing how the card and lubber line remain level even when in pitch and roll. This system is designed for sailing mono-hulls.

The specially built pivot and jewel assure precise suspension and the longest life of the unit and incorporates a shock absorbing system used in aircraft compasses.

Dual ALINCO Magnets are fitted under the card.

1) Pivot (super hard metal)

2) Jewel (sapphire)

3) Card Magnet

4) Compass Card

5) Inner Gimbal

6) Outer Gimbal

7) Gimbal Ring

8) Lubber Line

9) Capsule Dome

10) Rubber Gasket

Seamaster 4'' Card Compasses

The larger the compass card the easier it is to read, especially on a long night watch and therefore the more accurate the course steered. Aboard ships an eight-inch card would be normal with six-inch cards for wing compasses.

We offer our exceptionally good value Seamaster compasses with four options: the card can be flat or conical and the choice will largely be dictated by where the compass can be sited. If the helm can look down on the compass then a flat card can be chosen, as these are designed to be read across the top to the far lubber line, with the advantage that the dome acts as a lens, magnifying the scale and lubber line.

Novice helmsmen usually find it easier with a leading lubber line that moves around the card in the same direction as the bow.

If though the compass has to be mounted nearer the helm's line of sight and some people prefer this head up position and many boat consoles determine it, then an edge reading conical card will be necessary.

Conical cards are more expensive to produce than flat cards.

The other choices are either a 360º gimballed card and lubber line or a 60º tilting card.

Obviously a tilting card is a much less expensive option than a fully gimballed system.  Most sailing boats need a fully gimballed card as a gust will lock up a tilting card as, if beating to windward, you are already heeled 20° a further 10° in a gust will lock up a tilting card.  On the other hand in a motor boat or multihull, that seldom rolls more than 15° either way there is no point in the extra expense of a fully gimballed card.

These compasses are suitable for high-speed motorboats with shock absorbing to aeronautical standards.

SHOCK ABSORBING is ensured by the sapphire jewel being mounted on a spring, to minimise damage to the needle sharp hardened metal pivot, as is aeronautical practice.

60º tilting Flat Card 7800F £79.95

360º gimbaled Flat Card 7850F £89.95

60º tilting Conical Card 7800C £89.95

360º gimbaled Conical Card 7850C £99.95



Yachting Instruments Ltd


Sturminster Newton


DT10 2EH


Tel: +44(0) 1258 817662




Website & products updated September 2022


We are happy to provide expert advice and to answer all your questions about our products.