The Silva 4 Expedition is the company’s full-sized baseplate compass that has been in production for many years.
This model, in a slightly modified form, has been adopted and used by the British armed forces for many decades and the civilian market is equally as strong and will most likely be the first thing people think of when someone mentions a baseplate compass.
The Expedition 4 baseplate
The Expedition 4 baseplate is large compared to other compasses and is made from 3mm thick clear acrylic and all the markings are printed clearly in black.
It has 1:25k, 1:50k, and 1:40k map romer scales marked on it’s surface. Along the side edges of the baseplate are measuring scales in both inches and millimeters.
There is a magnifying glass embedded in the baseplate which is fairly powerful and useful for picking out fine details on maps and there is a circular stencil in the baseplate to assist in marking waypoints on a map.
A luminous direction travel marker is in place above the printed direction travel arrow which illuminates well at night after 4 hours of light exposure.
On the reverse side of the compass are three silicon feet. These assist in keeping the compass held in place when using it in conjunction with a map. This is a feature that many other manufacturers have chosen to disregard which is a shame as I have found it very effective offer the years.
There is a lanyard mounting point on the end of the compass which is an essential to keeping your compass secure.
The Expedition 4 bezel /capsule
The bezel on the Expedition 4 rotates smoothly while holding a bearing without slippage and it can be used easily while wearing gloves.
The degree markings on the face of the bezel are clearly printed in black in 2º intervals with highlights at 10º and 20º over the white inner part of the bezel.
Underneath the bezel there is a luminous segment marking the direction of travel. This segment works well and allows you set the bearing easily in the dark.
The Expedition 4 has a red declination adjustment scale printed on the base of the liquid filled capsule and there are dual colour orienting lines and a orienting arrow marked alongside it.
There is a luminous dot marked each of the arrow again to aid in night navigation. All of these markings are very clear and very easy to see when using with a map.
The needle is well balanced and marked up in red (North) and white (South) with a luminous marker on the northern part of the needle. The needle corrects itself to North very quickly and smoothly.
I have used various Silva Expedition 4’s over the past 25 years and I can honestly say that they have never let me down walking during day or night.
The design and function is perfect for the walker and it sets the benchmark for many competitors to try and emulate. An excellent and reliable compass.