Why you need more than one pair of binoculars onboard
Almost everyone carries a pair of binoculars onboard. Not only is it a safety issue, but also a learning and an observation tool. A good pair of binoculars gives great pleasure and will enhance your boating experience many times over.
One of our favourite pastimes is just sitting on deck or in the cockpit looking at other boats and people.
Nature itself is a wonderful backdrop to our common adventure while sailing and boating.
What is the perfect pair of binoculars for yachting?
Well, many will tell you that binoculars with a lower magnification factor is better for marine use to ensure a wider field of view. Reason is motion. The rationale is sound if you only will use the them while the waves and wind throw the boat around. It is hard to see much in binoculars with high magnification. Engine vibrations, shaky hands and other factors will also have impact on how well you can observe an object.
A few upmarket models come with a built in compass to give you precise bearing. Some even have built in rangefinders. Some now even have image stabilitation. Both distance and bearing are key factors in navigation and can be helpful when planning a tricky entrance to port or control AIS readings.
However, bearing and distance is usually read from other onboard instruments and are not required in a pair of binoculars. Nice to have, though.
Watertightness is self evident onboard. Make sure they are properly watertight. Read the small print as companies have a way of advertising this in different ways. Some marine binoculars are delivered with a floating strap which make a "binoculars over board" situation much easier.
Things have a way of fogging up in a marine environment. Especially when the temperature changes. Upmarket binoculars have the air inside them replaced with nitrogen. This secures fog free lenses and keeps moisture away from the fragile internals. It also keeps corrosion away. And we all know everything onboard corrodes over time.
There are two styles or shapes of binoculars and these are determined by what type of prism they use, either a Roof Prism or a Porro Prism design. We will not go into the more technical sides of that, other than writing that they both have advantages and disadvantages and so it is down to your specific needs, preferences and budget as to which you should choose.
Two important numbers
Binoculars are sold with two important numbers on them. The first number is the magnification factor and the second is the lens diametre. Most binoculars are between 7x and 12 x.
For observations in motion and where there is significant vibrations at sea, a 7 x magnification is often a good compromise and gives good field of view.
Why is lens diametre important?
Magnification is easy to understand, yet a pair of binoculars light gathering capabilities are more complex. For daylight use only, this matters less. But often sailors find themselves approaching a port after dark or do overnight passages. Then brightness is important. The bigger the aperture, the better. You can be around binoculars all your life, but the amazing sensation of looking into a pair of premium binoculars from Leica or Zeiss at dusk or dawns really makes you want to carry and use them forever.
Life in port or at anchor
All sailors spend more time in port than at sea. They go skiing, hiking and walk for miles in big cities. Others like to sit in the cockpit and observe their surroundings.
Manufacturers of binoculars often makes them for different uses. A wide field of view provides necessary overview when the distance to the observed object is short like in a city. A high magnification with a wide aperture can be used for astronomical observations. An extraordinary amount of detail in a another boat from across the bay can easily be revealed with high magnification. Studying at the ceiling in an old church can reveal amounts of detailed art. Even inspecting your own rig from a rooftop or bridge can be very useful.
The reasons for sailing may be different, but engaging and observing the natural world is perhaps a common denominator. As we carry different sails for different winds, we should perhaps carry different binoculars as well.