What to look for, and why. We only publish a guide once every factual claim in it can be traced to a source — the manufacturer’s own page wherever one exists — and each one lists its sources.
Magnification and steadiness, exit pupil and low light, image stabilisation, waterproof ratings and fogging, which binoculars float, built-in compasses and rangefinding reticles, focus, care and the lookout rule. Every claim cited to the makers or to the Navigation Rules.
Why carry a magnetic compass, mounts and dials, variation and deviation, where to install one and how to compensate it, zone balancing, lighting, handbearing compasses and electronic heading sensors. Every claim cited to the makers or to NOAA, NGA and the Coast Guard.
What US law requires of a boat's toilet, the Y-valve rule quoted word for word, manual, electric, vacuum, composting and portable heads, bowl sizes, smells and hoses, vented loops and seacocks, and upkeep. Every claim cited to the makers, federal law and regulations, the EPA, the Coast Guard or state agencies.
What a bilge pump can and can't do, pump types, rated flow against flow at head, automatic switches, wiring, discharge plumbing and alarms, then freshwater pumps, strainers and accumulators. Every claim cited to the makers, the Coast Guard, the NTSB or ABYC's voluntary 2005 bilge pump standard.
What the law requires, USCG approval, the new Level labels, turning, foam or inflatable, how inflators fire, rearming, age limits, children's jackets, harness jackets and why to wear one. Every claim cited to the regulations, the Coast Guard, boating-safety bodies or the makers.
What a working autopilot is made of, sizing, tiller and wheel pilots, below-deck and hydraulic drives, outboards, rudder references, setting up, wind and route modes, and keeping watch. Every claim cited to the makers or to the Navigation Rules, the MAIB and the NTSB.
Wind sensors and the boxes they need, apparent and true wind, depth frequency and mounting, paddlewheel or ultrasonic speed, housings and hull materials, and fitting a through-hull safely. Every claim cited to the makers or the NMEA.
What's in the box, touchscreen or keys, charts and who makes them, sonar and transducers, NMEA 2000, sailing features, autopilots and instrument displays. Every claim cited to the makers or to NOAA, the NMEA and the Coast Guard.
Where a diesel heater goes on a boat, the exhaust, fuel and power, sizing, CO alarms, and what the makers' own manuals say. Every claim cited to the heater makers or to official sources, among them the Coast Guard, ABYC, Minnesota's DNR and the UK's accident investigators and Boat Safety Scheme.
Handheld or fixed, power and range, waterproof ratings, floating, DSC and the MMSI, channels, weather alerts, batteries and licences. Every claim cited to the radio makers or to the FCC, Coast Guard, NOAA and IEC.
Size numbers and power ratios, one to three speeds, self-tailing jaws, replacing a winch, and choosing a handle. Every claim cited to the makers' own pages and manuals.
What each kind of sailing block is for — fiddle, snatch, cheek, foot, stand-up, ratchet and more — and how bearings and heads differ. Every claim cited, almost all to the makers' own pages.