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How To Find The Right Underwater Connectors For Your Project

Posted by Evan Freemon on March 30, 2022 | Updated on December 1, 2023
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Wet-mate connectors are the linchpin of a successful underwater application. Unless you identify the right subsea connectors for your project, it could be dead in the water — or, at the very least, require frequent, expensive repairs.

To prevent that, let’s review the typical options available for underwater connectors, the benefits and shortcomings of each, and what considerations should be key to your decision-making process.

Types of Underwater Connectors

Underwater connectors, also known as wet-mate connectors, subsea connectors or marine connectors, are designed to be mated or unmated in wet environments and capable of withstanding the most extreme environments, from corrosive seawater and pressure to vibration and shock.

A traditional underwater connector relies on a watertight seal. Several variations have been developed over time to achieve this, including:

Rubber-molded wet-mate connectors

A wet-mate connector is created between a female connector end and a glass-reinforced epoxy bulkhead connector through a locking sleeve as well as neoprene or polyurethane over-molding.

Rigid shell wet-mate connectors

Rigid shell wet-mate connectors are molded into a rigid body to offer greater stability, strength, and lockability. Two connector halves are screwed together, sealing the junction with an O-ring.

Fluid-filled wet-mate connectors

A chamber is filled with oil or another dielectric fluid to isolate the contacts from water. As the ends are mated, the contact pins are wiped clean by the diaphragm in the face of the receptacle. 

Inductive Couplings

These pinless connectors connect magnetically without exposing any conductive parts to the outside environment.

How do you determine which type of standard wet-mate connector is best for your needs? Let’s take a deeper dive into the specs to consider for each.

Factors to Consider When Choosing Underwater Connectors

The industry’s long standing underwater interconnect solutions vary in application, material, and design. A typical underwater connector often features O-rings, gasket seals or oil bladders and copper contacts. 

Before settling on a product, be sure to evaluate the following key criteria.


The metal used must be strong enough to withstand its intended marine environment. Depending on a project’s needs — such as extreme corrosion resistance, tensile strength, minimal electrical conductivity, or a high melting point, 316 stainless steel, Inconel and titanium are considered three materials of choice. 

316 stainless steel is a typical choice as it is well-equipped to resist corrosion after undergoing design and manufacturing processes that involve welding. It also withstands high-corrosion environments and boasts considerable resistance to heat.

A variation of stainless steel, Inconel is considered a superalloy due to its mechanical strength, surface stability, and corrosion resistance. 

Few pure metals have more strength than titanium. It has an extremely high corrosion resistance and a tensile strength at least double that of aluminum.


From a cost perspective, stainless steel is a reasonable choice for wet-mate connectors and will stand up to the elements quite well. However, for applications that require truly exceptional corrosion and heat resistance, titanium is the preferred option. 


Peak performance in the field is where it matters. Some wet-mate connectors boast guarantees of remaining operational underwater for up to 25 years along with long-term water resistance while others are considered difficult to implement in the field due to a tendency to leak or become compromised at a certain pressure rating.


As the depth of your application plummets further underwater, the equipment is subjected to increasing amounts of pressure reaching up to and often greater than 10,000 psi. This amount of force can negatively impact any number of components, increase system failures or jeopardize operations.

Cable Assembly

Typical connectors come in a wide range of cable assemblies, including electrical, fiber optic, or pressure-balanced oil-filled. 


Wet-mate connectors are rated for an application’s specific depth and pressure. For example, a subsea connector may have a mated pressure rating up to 20,000 psi but is tested in an even more rigorous marine environment.

Lead Time

A long lead time generally is required as traditional wet-mate connectors take 18 weeks, or more than 4 months, from the time an order is placed until delivery (and that’s without any disruptions in the supply chain). 

Researching each of these seven key criteria relative to the specifications needed for your project will help in identifying the best traditional wet-mate connectors for your application.

It’s important to note that regardless of the advancements made over the years, underwater connectors still mix electricity with water. Traditional underwater connectors attempt to exclude water from their contacts by using rubber seals, oil or moving parts.

Despite the industry’s best efforts, these wet-mate connectors are expensive, run the risk of high failure rates due to corrosion and other environmental factors and pose a potential safety risk.

A “Water-Compatible” Wet-Mate Connector

While engineers have made improvements in electrical wet-mate connector technology over the past 150 years, there are still disadvantages to tried-and-true traditional electrical connector interconnect solutions.

Imagine a connectivity solution that works with an underwater environment, utilizing the water to achieve optimal performance, instead of working against it. Thanks to the transition metal called niobium — known for its corrosion resistance & hypoallergenicity, a new wet-mate connector does just that.

The first of its kind, iCONN’s wet-mate connectors utilize Northrop Grumman’s Patented NiobiCon Technology, which allows the connectors to intentionally let water in and can be mated and demated while fully exposed to water. The contacts will not corrode, current does not continue to flow through the water when mated and unmated and electronics will not short out

This new evolution of wet-mate connector technology upends the industry’s longstanding design. It can be used on the surface, underwater while submerged at any depth or wherever there is a wet, corrosive environment, such as in chemical processing plants, agriculture, automotive applications and undersea operations & aquaculture.

Unlike its counterparts on the market, iCONN’s wet-mate connector combines technology with the materials natural ability to produce an insulating film when the connector’s contacts are exposed to water.

Many traditional wet-mate connectors have a stainless-steel construction and use gold plated copper contacts. Instead of copper contacts, iCONN utilizes niobium, which delivers the same level of corrosion resistance as titanium — the premier material for corrosion resistance.

When niobiCONN contacts are energized and exposed to water, the contacts create their own passive, insulating film around the niobium contacts to protect the users and environment from electricity. This insulating film — 99.79% thinner than a strand of human hair — provides electrical connectivity and scrapes off as the connectors are mated. When the contacts are demated, the insulating film forms again within milliseconds.

The niobium contacts are self-healing and are safe from direct contact with power applied, up to 60VDC applications.

While a traditional wet-mate connectors can begin to corrode when exposed to water, the insulating film on iCONN’s wet-mate interconnects offers a more robust solution for subsea & wet location applications & electronics.

iCONN’s aptly named niobiCONN™ wet-mate connectors can be mated and disconnected wet or fully submerged without the standard risk of corrosion or safety hazards — delivering safe and reliable electrical connectivity in water.

niobiCONN™ connectors also can be customized to meet the parameters of your project and at a reduced lead time by more than half compared to traditional underwater connectors — 18 weeks down to an average of six to eight weeks from order to delivery.

Ready to see how the niobiCONN™ wet-mate connectors will enhance your project? Contact an iCONN Systems sales representative to learn more.


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