12V vs 24V Autopilot Systems: What to Compare

Read the voltage line first

A marine autopilot is an electrical system, and the first voltage question is the boat's, not the autopilot's. The 'Power Usage' row on a listing tells you the supply the unit is described for. Furuno's NavPilot 300 page, for example, lists 'Power Usage 12-24 VDC', meaning the unit accepts either a 12V or 24V DC supply. A row like that answers two boat questions at once: whether the control head matches a 12V boat and whether it matches a 24V boat. For the wider question of what a boat's voltage system means, see voltage systems.

Raymarine's drive unit page describes its Type 0.5 hydraulic pump as an autopilot drive for boats with hydraulic steering 50 to 110cc and 12-volt power systems. That wording ties the drive to a 12V boat, the kind of detail to look for on each drive and pack before you compare.

Where voltage appears on a listing

Voltage is rarely in the title of a pack. It usually sits in the specification table under a row named 'Power Usage', 'Power Supply' or 'Voltage'. When a listing does not carry that row, the maker's page is the source to read. This catalogue compares stated details, so the absence of a voltage row is a sign to look at the maker's page before choosing.

• Look for a 'Power Usage' row on the control head or course computer
• Look for a voltage word in the drive unit description, such as '12-volt power systems'
• When no voltage appears, treat it as a question for the maker's page

Drive unit voltage and your steering

The drive unit is the part that interfaces with the boat's steering system, as Raymarine's drive unit page puts it. Autopilot drive units come as hydraulic pumps, rotary drives and linear drives, and the drive types article explains how each name reads on a listing. Each drive in a pack is described against the steering system it is for, and sometimes against the boat's voltage.

A listing that names the steering (hydraulic, mechanical, tiller) but not the voltage still leaves the voltage question open. The boat's electrical system is fixed; the autopilot parts you choose must be described for that system. If a drive is described for 12-volt power systems, as the Raymarine Type 0.5 pump is, and your boat runs 24V, that is a question for the maker's page.

Questions to ask before you choose

These questions are worth asking before you compare packs:

They are questions, not installation steps. The maker's manual and a qualified installer handle wiring and commissioning; this article only tells you which details to compare before buying.

• What voltage is the boat's electrical system? The boat maker's manual or a qualified marine electrician answers this.
• What voltage does the drive unit in the pack accept? The maker's page for that drive is the source.
• Does the control head accept the same voltage? Look for a 'Power Usage' row such as 12-24 VDC.
• Does the course computer in the pack share the supply? The pack's page and the maker's manual cover this.
• If the listing shows no voltage at all, what does the maker's page say?

What a listing cannot tell you

A listing is a set of stated details, not a verdict on the water. No listing on this site claims a boat length, displacement or weight a unit suits, and none claims course-holding accuracy, power draw in amps or watts, or behavior in waves. The comparison is on stated details only. The voltage row, the steering type, the drive in the box and the control head in the box are the facts to compare. For a closer look at what a 'Power Usage' row does not tell you about current draw, see power consumption.

If you want more than that, the next stops are the maker's page for the exact part number and a dealer for your boat. The same discipline applies to a network: the NMEA 2000 standard describes how certified equipment shares data over a single channel, but whether your chartplotter and pilot actually work together is a question for the maker pages of both devices.

Matching the voltage to your boat

The practical rule is simple: the boat sets the voltage, and the autopilot parts must be described for it. If your boat runs 12V, a pack whose control head shows 12-24 VDC and whose drive is described for 12-volt power systems gives you a consistent set. If your boat runs 24V, look for parts whose pages or listings name 24V or the same 12-24 VDC range.

When two packs look equal except for the voltage wording, the one whose parts are described for your boat's system is the one to compare first. The same comparison logic applies when you are choosing between a complete pack and a core pack: the voltage row decides which one can work on your boat at all. The complete pack guide and the core pack guide show how the drive and head in the box change the choice, and the hydraulic autopilot guide covers steering-driven decisions.

One voltage or a range

A listing can state a single voltage, like a page that says a unit is for 12-volt power systems, or a range, like '12-24 VDC'. A range is easier to match because it covers both 12V and 24V systems without asking which one your boat runs. A single-voltage description is stricter: the unit is described for that system only, and the maker's page decides the rest.

Keep that wording in mind when you read a pack title. A pack named after the drive or control head, such as a NavPilot or EV pack, still carries its voltage detail in the specification row. The title names the model line, not the electrical system.

What to pick for your situation

Questions

What does 12-24 VDC mean on an autopilot listing?

It means the unit is described to accept either a 12V or 24V DC supply. Furuno's NavPilot 300 page shows 'Power Usage 12-24 VDC' as an example.

Is a 24V autopilot better than a 12V one?

There is no better as a general rule. The boat's electrical system decides which voltage the parts must accept. A unit described for 12-24 VDC covers both; a unit described only for 12-volt systems is a question for the maker's page on a 24V boat.

Where do I find the voltage of my boat's electrical system?

The boat builder's manual is the first place. A qualified marine electrician can confirm it. The autopilot listing will not tell you what your boat runs.

Why does the drive unit matter for voltage?

The drive is the part that connects the autopilot to the steering. Raymarine's drive unit page describes the Type 0.5 pump for boats with hydraulic steering and 12-volt power systems, which shows how a drive is tied to a voltage. Always read the drive description and the maker's page.

Does NMEA 2000 care about 12V or 24V?

The NMEA 2000 standard describes data sharing over a single channel, not a power supply. The voltage question is separate and comes from the autopilot listing and the maker's page.

Can this site tell me if a 12V drive works on my 24V boat?

No. The site compares stated details only. The maker's page for that drive is the source for the voltage it accepts, and a dealer can confirm it for your boat.

What should I read on a pack title for voltage?

Pack titles name the model line and the drive or control head, not the voltage. The voltage sits in the specification row, so read that row and the maker's page, not the title alone.

Does an autopilot replace a lookout?

No. The U.S. Coast Guard Boating Safety division is dedicated to reducing loss of life and injuries on U.S. waterways by improving the knowledge, skill and abilities of recreational boaters. Keep watch and take a boating safety course.