Good drawings take time to make. Time costs money. Therefore, good drawings are not cheap.
Some boat builders seem to think that this logic leads to a fourth point: "Therefore, we will not include drawings."
Er, guys? Not cool. Seriously, not cool. Just see what happens the very first time the owner has to have something fixed, and the technician spends most of a day rooting around in the bilges trying to figure out where the hell all the wires are going.
Almost as bad as the boat with no drawings is the boat with inaccurate drawings. Maybe something got changed on the shop floor, maybe there are dealer-installed accessories. Whatever the cause, the result is a situation where what's acutally in the boat doesn't match what's expected. That means time and money will be wasted trying to figure it out.
The problem only gets worse as technology advances. A relatively simple modern yacht, about 12 metres (40 ft) long, might have:
- A main panel with 20 or more DC breakers
- Hundreds of metres of light DC power cables
- 50 m of heavy duty (>100 amp) DC power cables
- An NMEA 2000 bus comprising ten sensors, 50 m of N2K cable and 40 to 50 connections
- Radar, VHF and SSB cables up the mast
- A harness of ten or twenty wires for engine control and instrumentation
- Battery monitoring wires for the amp-hour meter, the alternator regulator, and the shore-power charger
- A bank or two of solar panels, plus their wiring, charge controllers and circuit breakers
For a "typical" level of complexity, you can add a couple of AC inverters (and their wiring, and breakers, and distribution panel), the control electronics for a watermaker and refrigerator, audio and video equipment, a fishfinder, and a dashboard full of the latest multi-function displays. The latest fad is distributed power systems- little black boxes that turn virtual circuit breakers on and off in response to digital commands sent over the vessel's communication bus.
There is no way anyone is going to be able to make sense of all this in five years if it isn't written down.
Furthermore, the computerized parts, such as the N2K bus and the distributed power nodes, will be simply impossible to troubleshoot later on, unless all of their configuration details- and the software tools to implement them- are provided to the owner in an appropriate format. It is for this reason that I am extremely reluctant to specify any components that require closed, proprietary computer systems for their installation and maintenance.
So, some solutions.
Equipment manufacturers: Use standard communication protocols such as NMEA 2000 wherever possible, and follow the standard (none of this "we'll add our own proprietary PGN" bull). If you have a gadget that simply must use a proprietary, non-standard protocol, then document it thoroughly- including connector pinouts, signal levels and the data format specification- and post that on your website. If proprietary software is needed to configure or troubleshoot your device, make that software available for download- or, better yet, make it an open-source project and see what cool stuff the community can create based on your devices.
Boat builders: Draw up a standard schematic for the base model of each of your boats. When a customer orders options, add them to the schematic for that boat. Make sure that what's happening on the shop floor and what's going onto paper are the same thing. Then, when the customer takes delivery, include the schematics in the owner's manual. (And, ideally, also in a format that can be amended as the boat gains new gadgets later in life.)
Owners: Keep the electrical drawings updated as you add new systems. If you don't have any drawings, go down to the boat (when you have a few hours to kill) and start making notes on how everything's connected.
Yes, drawings do require time (and therefore money) to make. And they aren't going to be complete, or correct, right off the bat: they will change as the shop crew works around problems, and as the owner requests changes and additional options. If the boat's systems are non-trivial, though, accurate drawings are essential- both to the sanity of the technicians who will visit the boat in the coming years, and to your reputation as a builder.