MK11 Submarine Escape Immersion Equipment (SEIE)

Advanced SEIE for Maximum Submariner Safety

The SEIE MK11 suit is trusted by over 20 of the world’s leading naval forces to provide submariners with exceptional protection during emergency escapes from pressurised environments. Beaufort has developed the SEIE MK11 as a fully integrated system, combining both the immersion suit and single-seat liferaft into one advanced solution. Proven to reduce the likelihood of end-user CO2 saturation typically found in more segmented products, the MK11 ensures superior safety and reliability.

Performance

When underwater emergencies occur, a trusted, proven partner is essential. Our submarine escape and abandonment systems are engineered for precision, speed, and survivability, delivering reliable performance under extreme pressure and time-critical conditions. From deep escape scenarios to surface evacuation, they enable rapid, controlled responses when it matters most.

Innovation

We are continually advancing our submarine escape and abandonment capabilities to meet the evolving demands of naval operations. Through new material sciences, technological innovation and strategic partnerships, we push the boundaries of survivability — developing solutions that set new standards in performance, integration and reliability beneath the surface.

Protection

Sub-surface emergencies demand absolute confidence in protective systems. Our escape and abandonment solutions are designed to safeguard submariners from depth to recovery, delivering thermal insulation, flotation, and life-support performance under the harshest conditions. Proven through rigorous testing, they provide the protection needed when submariner survival is the priority.

Product Benefits

Durability:
Modern, lightweight materials increase durability and minimise wear and tear, ensuring long-term use in demanding environments.

Thermal Protection:
Enhanced thermal liner and non-slip soles offer protection from cold and wet conditions, increasing survivability during extended periods at sea.

Comfort:
The suit’s design prioritises comfort, with features like improved foot and ankle profiles, ensuring quick donning over navy-issue footwear.

Reduced CO2 Saturation Risk:
The MK11 SEIE reduces the likelihood of CO2 saturation during escape procedures, an issue common in more segmented products.

Key Features

Comprehensive Protection:
Built to withstand extreme conditions, the SEIE MK11 incorporates advanced thermal insulation, ensuring submariners’ safety in the most challenging environments.

Integrated Liferaft:
The fully integrated liferaft deploys seamlessly with the suit, offering extended survival times on the water.

Enhanced Functionality:
Patented design features such as the rip-zip system for rapid CO2 venting and improved sizing adjustments ensure ease of use and comfort for the wearer.

Works with Global Air Systems:
Fully compatible with air systems worldwide, the MK11 SEIE is flexible and reliable no matter where it’s deployed.

Certified and Reliable:
The SEIE MK11 is tested to stringent standards, providing submariners with reliable protection at depths of up to 200 metres when connected to the Hood Inflation System. Backed by a global service network and regular servicing intervals, the SEIE MK11 ensures operational readiness when it matters most.

Proven Compatibility with Advanced Systems:
Fully tested, integrated, and compatible with the Hale Hamilton valve and HABETaS® system, offering a safe and effective method for submarine tower escape.

Technical Specification

SEIE Servicing Recommendations:	Service your MK11 SEIE every 3 years at certified centres to ensure maximum Submariner safety, reliability, and performance.
Safety at Depth	Designed to escape from 180 metres
Improved Air Usage	Uses 30% less air than earlier designs
Rapid Ascent	Provides over 170N of buoyancy
Keeps Crew Warm	Thermal protection for improved survivability
Excellent Buoyancy	Liferaft buoyancy made from 2-ply butyl
Liferaft Integration	Fully integrated single-seat liferaft offering over 24 hours of survival
Viewing Panel	Large ascent hood panel for better manoeuvrability and awareness
Soles	Non-slip thermal soles for protection and grip
Size Adjustments	Torso, crotch, and leg straps for secure, adaptable fit

Information Downloads

Technical Datasheet

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Events Calendar

Verticon

9 – 12 March 2026

SAFE Europe Symposium

2nd – 4th March 2026

Land Forces

6 - 8 October 2026

SOFIC (Special Operations Forces Industry Conference)

18–21 May 2026

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