Solar is the quietest way to keep a bank topped up, and the easiest to over-promise. Output on a boat is governed less by panel rating than by shading, angle and how the array is wired.
This guide covers the choices that decide whether an installation actually contributes.
Flexible panels conform to coachroofs and biminis and are walkable in the right locations, but they run hotter against a surface and generally have a shorter service life than framed rigid panels.
Rigid panels on a gantry or rail mount usually produce more per watt because they sit in clear air and can be angled — at the cost of windage and deck space.
A boom, a furled headsail, a radar dome or standing rigging crossing a panel does not reduce output proportionally — depending on the panel and how the array is wired, a small shadow can cut a string dramatically.
That is why array layout and whether panels are wired in series or parallel matters as much as total wattage on a sailing boat.
The useful question is how many amp-hours a day the boat consumes and what proportion you want solar to cover through the season you actually use the boat. Winter output on the South Coast is a fraction of midsummer, so a system sized for July will not hold a bank alone in December.
An MPPT controller matched to array voltage and set for the battery chemistry recovers meaningfully more than a basic PWM unit in most marine layouts. Cable runs from deck to controller need sizing for the current and the distance, and the array needs proper fusing and a means of isolation.
For a modest consumption boat over the summer, often yes. Across a British winter, or with fridges and autopilots running, solar is usually one source among several.
No. Panels need direct light; mounting on top of a bimini is a common and effective solution.
Panels in different shading conditions — for example coachroof and gantry — often perform better on separate controllers than combined into one string.
Yes, and an MPPT that joins the existing network will share data with the rest of the system.
We survey the boat, look at the shading, then quote an array and controller sized to how you use her.