How to Choose the Correct ANL Fuse for a Bow Thruster

Introduction

Electric bow and stern thrusters are among the most power-demanding electrical systems installed onboard modern yachts and professional vessels. During manoeuvring, thrusters draw extremely high current for short periods, creating significant electrical loads on batteries, cables and control components.

Selecting the correct ANL fuse is essential to protect the entire DC electrical system from overloads, short circuits and overheating. Using an incorrectly sized fuse may lead to system failure, damaged wiring or even fire risks.

This guide explains how ANL fuses work, how to select the correct rating and which fuse is required for each Max Power thruster model.

What Is an ANL Fuse?

An ANL fuse is a high-amperage DC protection device designed for heavy electrical loads commonly found in marine installations.

Unlike standard automotive fuses, ANL fuses are built to handle:

very high current peaks
short-duration load spikes
vibration and marine environments
continuous electrical reliability

In thruster installations, the ANL fuse acts as the primary safety barrier between the battery bank and the motor.

Why Thrusters Require Dedicated Fuse Protection

Bow thrusters operate differently from most onboard equipment.

When activated, a thruster motor can instantly draw hundreds of amperes. Without proper protection, excessive current may cause:

overheating of power cables
battery damage
failure of solenoids or contactors
electrical system shutdown
fire hazards

A correctly selected fuse allows normal operational current while disconnecting power instantly during abnormal conditions.

Recommended ANL Fuse Selection for Max Power Thrusters

Selecting the correct ANL fuse is essential for safe thruster operation. The table below shows manufacturer-recommended fuse ratings based on thruster model and system voltage.

Thruster Model	System Voltage	Required Fuse Rating	Fuse Code	Fuse Holder
CT25	12 V	150 A	636342	636347
CT35 / CT45	12 V	175 A	636343	636347
CT60 / CT80 (Tunnel)	12 V	225 A	636344	636347
CT60 / CT80 (Compact Retract)	24 V	175 A	636343	636347
CT100 / VIP150	12 V	400 A	636346	636347
CT125 / VIP150	24 V	225 A	636344	636347
CT165	24 V	325 A	636345	636347
CT225	24 V	400 A	636346	636347

Importance of the ANL Fuse Holder

All ANL fuses must be installed using a dedicated fuse holder.

The Max Power ANL Fuse Holder (636347) provides:

insulated protection against accidental contact
secure cable mounting
improved heat dissipation
safer inspection and replacement
compliance with installation standards

Installing a fuse without a proper holder is not recommended in marine environments.

Where Should the Fuse Be Installed?

Best practice installation guidelines:

install fuse close to the battery positive terminal
recommended distance: 20–40 cm from battery
use marine-grade cables
ensure strong mechanical mounting
avoid humid or poorly ventilated areas

Correct placement significantly improves safety and system reliability.

Common Installation Mistakes

Avoid these frequent errors:

❌ Installing oversized fuse ratings
❌ Using automotive fuses instead of marine ANL fuses
❌ Installing fuse far from battery bank
❌ Poor cable termination
❌ Loose electrical connections

These mistakes reduce protection efficiency and increase electrical risks.

How to Select the Correct Fuse

Always base fuse selection on:

Thruster model
System voltage (12V or 24V)
Manufacturer recommendations
Proper cable sizing

Never increase fuse amperage to prevent blowing — this removes system protection.

Related Guide

For full thruster selection and installation guidance, read:

Bow Thruster Selection Guide Europe

Why Choose Gaelix Marine Service

Gaelix Marine Service supplies genuine Max Power components with worldwide delivery and professional technical support for yacht owners, installers and shipyards.

We provide:

original spare parts
expert installation advice
compatibility guidance
global shipping solutions

FAQ

Andreas Nikolaou (Boat Owner, Greece):

Why does my bow thruster need such a large fuse?

Thrusters require very high current for short periods. The fuse protects wiring and batteries while allowing normal operational peaks.

Marco Bianchi (Marine Installer, Italy):

Can I use a higher amperage fuse for reliability?

No. Oversizing a fuse reduces protection and may cause serious electrical damage.

Peter Hansen (Skipper, Denmark):

Do all thrusters use the same fuse holder?

Max Power ANL fuses use a dedicated holder (636347), designed for safe marine installation.