Sealing solutions from APM Hexseal 24 June 2022

By sealing marine equipment, manufacturers and end users not only protect sensitive internal electronics, they also mitigate the risk of hazardous compounds leaking and spreading into the world’s waters. Here, Jackie Hackett, director of global sales and marketing at APM Hexseal, explains how its sealing boots can protect the internal and external components of an electronic system.

Exposure to environmental substances, such as water, chemicals, dirt, and salt, can cause significant damage to electronic equipment and systems. Depending on the system and the contaminant, contact can trigger system outages or lead to complete system failure. Either of these conditions leads to unplanned downtime, increased equipment costs, and loss of profits.

For many industrial electronic control systems, especially those employed in marine environments, sealing boots provide a solution to these issues and still allow the switch to function and actuate as intended. Properly protecting these vulnerable electronic and mechanical systems, ensuring their continued operation, is crucial to the safe navigation of the world’s waterways.

Sealing boots are devices that protect the internal and external components of an electronic system. They are used in a variety of marine applications, including military destroyers, commercial fishing boats and deep sea submarines. In these extreme environments, sealing boots maintain the integrity of sensitive electronic components by sealing stuff out and protect vulnerable ecosystems by sealing stuff in.

Seal stuff out of sensitive marine electronics

Today’s marine vessels use high-tech electronic systems to plot their course; control operating equipment in various parts of the vessel; monitor and protect against external conditions such as weather and rough seas; and keep internal environments safe and comfortable for crew members and cargo. To maintain optimal performance in these systems, marine vessel and equipment manufacturers employ sealing boots to provide corrosion protection, prevent contamination, avoid overloads and short circuiting, extend equipment service life, as well as ensure long-term system security.

APM Hexseal manufactures a variety of different types of boots designed to protect various electronic components in marine systems, while still allowing the switch to actuate freely. These sealing boot offerings include circuit breaker boots, toggle boots, as well as pushbutton boots. Circuit breaker boots are available in ‘back of panel’ or ‘front of panel’ mounting styles. On both models, a continuous sealing rib wraps around the lower portion of the flange to provide a long-lasting seal. These boots are suitable for protecting electronic components from short circuiting and extending their service lives.

Also available from APM, toggle boots consist of moulded silicone placed over threaded mounting nuts. This design enables fully enclosed, single piece components that cover the switch to be produced. Available in full and half styles, APM Hexseal’s toggle boots include a sealing rib that keeps components securely attached to their mounting panels. These boots frequently find application protecting all types of toggle switches on fishing equipment and boat control panels.

Initially developed for military purposes, pushbutton boots are designed to provide push button switches protection against extreme environments, such as low or high temperatures, inclement weather, salt, dust, dirt, humidity, etc. Pushbutton boots from APM meet MIL-DTL-5423 specifications. When used, these devices seal electronic switches and safeguard them from potentially harmful external elements that contribute to corrosion and other damages.

Seal stuff in to protect delicate ecosystems

In addition to sealing environmental substances out to protect sensitive internal electronics, sealing solutions also seal hazardous compounds in to protect vulnerable ecosystems. From deep-sea locations to inland waterways, the waters and surrounding lands used for marine activities are at risk of contamination from leaking marine and undersea vessels. Depending on the compounds or pollutants contained within, when these vessels leak, the impact on the local ecosystem can be catastrophic.

Taking preventative measures

As a whole, oil spills are one of the biggest contributors to water pollution. Although big oil spills do have significant and lasting effects on the environment, collectively, smaller oil spills – such as from refueling or bilge discharging operations – can have a greater environmental impact.

Taking preventative measures, such as installing sealing boots and other sealing solutions, helps reduce the impact of marine operations on delicate ecosystems. By sealing marine equipment, manufacturers and end users not only protect sensitive internal electronics, they also mitigate the risk of hazardous compounds leaking and spreading into the world’s waters. Implementing regular and thorough inspections of equipment and systems could also prevent a potentially hazardous leak or malfunction. Sealing boots and fasteners from APM are reusable, making them a smart economic choice for items requiring frequent access or maintenance.

APM Hexseal designs and manufactures a wide range of sealing solutions to suit the unique needs of clients including circuit breaker boots, Seelbolts®, Seelnuts®, and Seelskrews®, Seeloc® washers, as well as toggle, pushbutton, and rocker boots.

Deputy Editor

Claire Aldridge Deputy Editor t: +44 (0) 1727 743 889


Having spent a decade in the fastener industry experiencing every facet – from steel mills, fastener manufacturers, wholesalers, distributors, as well as machinery builders and plating + coating companies, Claire has developed an in-depth knowledge of all things fasteners.

Alongside visiting numerous companies, exhibitions and conferences around the world, Claire has also interviewed high profile figures – focusing on key topics impacting the sector and making sure readers stay up to date with the latest developments within the industry.