A full rewire is one of the larger projects an owner takes on, and most of the frustration we see comes not from the electrical work itself but from poor sequencing, work started before a proper survey, or systems reinstated before the boat's other trades have finished disturbing the same spaces. A clear project plan avoids redoing work twice.
This guide sets out the order we work through on a typical rewire, what actually drives the cost up or down, and how to phase the project sensibly if the whole boat cannot be done in one go.
The first stage is a full survey of the existing installation, identifying which circuits are being kept, which are being replaced, and where new circuits are wanted that did not exist before. This is also when cable routes, panel locations and equipment positions get agreed, because moving a distribution panel after wiring has started is expensive rework.
A written specification and a circuit list, what feeds what, cable sizes and fuse ratings, comes out of this stage. Skipping it in favour of getting started saves a week up front and typically costs far more in revisited work later.
Rewiring generally runs old cable removal, new cable runs, then termination and testing, in that order through each section of the boat rather than trying to do the whole boat at every stage simultaneously. Removing old cable first, rather than running new cable alongside it, avoids conduits and cable runs becoming overfilled and gives an honest look at the condition of anything hidden behind panelling.
Where other trades, joinery, engine work, tank replacement, are happening at the same time, wiring needs coordinating around them. Running new cable through a space before joinery work that will disturb it is a common and avoidable cause of damage and delay.
Access is the biggest single factor, boats with headlinings, extensive joinery or tight steering gear spaces take considerably longer to run cable through than open bilge and locker access. The number of circuits and their complexity matters more than boat length on its own; a heavily equipped motor yacht with multiple systems can cost more to rewire than a larger, simpler sailing boat.
Panel and distribution board replacement, rather than reuse, adds cost but is usually worthwhile on an older boat where the existing panel is undersized for modern loads or uses obsolete fuse types. Labelling and documentation standards also vary between installers and affect both price and the value of the finished job to a future owner or surveyor.
A full rewire on a mid-sized cruising boat with reasonable access typically runs to several weeks of continuous work once the specification is agreed, longer where access is poor or where the boat is being worked on alongside other major projects. Owners planning a rewire around a launch date should build in contingency, since discovering additional deteriorated wiring or damaged bulkheads behind panelling during removal is common rather than exceptional.
Ordering equipment, panels, breakers, specific cable types, can also affect timescale, particularly for less common items, so confirming lead times during the specification stage avoids the work stalling partway through.
Where a full rewire in one go is not affordable, the sensible phasing is safety-critical circuits first, engine start and stop, bilge pumps, navigation lights and any circuit showing signs of heat damage or poor previous repairs, followed by the main distribution and house circuits, with lower-priority additions such as extra sockets or entertainment wiring last.
A phased approach only works well if the initial survey and specification cover the whole boat, so that later phases connect into what was done first rather than requiring parts of the early work to be redone.
It varies too much by boat size, access and equipment count to give a single figure responsibly; a written quote following a proper survey is the only reliable way to know, which is why we always survey before pricing.
Much of the work can, though sections involving through-hull fittings, bonding or work below the waterline are usually easier and safer ashore.
Coordinate them. Structural, joinery and tank work that disturbs the same spaces should generally happen before final cable runs and termination, with rough cable routes agreed early so other trades can work around them.
Often yes, particularly where the hull and rig are sound, since a rewire addresses one of the most common causes of ongoing electrical faults and safety concerns without the cost of a new boat.
Not for most of the process, though being available for the specification stage and final walkthrough helps confirm equipment positions and priorities match what you want.
We survey the whole boat, agree a written specification, then sequence and quote the work in phases if needed. Free initial assessment.