Connectors and penetrators

Let’s talk connector and penetrator types most commonly used in underwater applications. There are many requirements for the connectors and penetrators, probably most important of which is underwater rating. Typically underwater rating represents the guaranteed depth a device can operate to, and for simplicity, can be split into three categories: <10 feet (your typical snorkeling depth) where most consumer or hobby grade equipment that claims underwater rating can operate.

Down to 600 feet is typical comfortable ROV operations depth. All of the described connectors except Binder 770 are rated for this segment and even deeper. Below that comes professional ROV territory. Acrylic enclosure tubing is no longer an option. Components structural integrity becomes a very important metric. Lights needed to illuminate the surroundings becomes a burden on the power systems. But nevertheless this does not stop ROV enthusiasts from challenging these depths. With this being said it is very important to properly select your connectors for each specific application. Here is a list of connectors with some relevant properties.

Potted Cable Penetrator

This potted cable penetrator is a simple solution to waterproofing your robot. It’s basically a bolt with a hole that the thruster cable can be glued (potted) into to provide a waterproof connection through watertight enclosures, boxes, panels, etc. Although the potting procedure requires some additional tooling and marine grade epoxy, it is pretty straight forward. The drawback of any potted connector is that the potting tends to degrade over time, so a good practice would be to include checking the penetrator integrity in your preflight checklist.

Installation Difficulty	🧩 🧩
Max Wire Size	4-8 mm
Pin Count	ANY
Always Connected	✅
Durability	🏺🏺🏺
Price	﹩

Wet Link Penetrators

The WetLink Penetrator (WLP) is a next-generation solution for low-cost, high pressure, high reliability sealing of electrical cables as they pass into enclosures or other devices. It’s rated to a depth of 950 meters (3,116 feet) and compared to subsea connectors or penetrators, the WetLink Penetrator is a fraction of the cost while offering validated reliability that you can count on.

Installation Difficulty	🧩
Max Wire Size	4-8 mm
Pin Count	ANY
Always Connected	✅
Underwater Raiting	950m
Durability	🏺🏺🏺
Price	﹩

Blue Trail Engineering Cobalt Series

Blue Trail Connectors are the cheapest way to have a detachable cable cable for your ROV. With an underwater rating of up to 600m, the only drawback is that the Cobalt series is only capable of DRY mating, meaning that all connections are done shoreside. A locking ring is a great accessory that allows a more secure connection.

Installation Difficulty	🧩 🧩 🧩
Max Wire Load	40A
Pin Count	2-8
Dry Mating	✅
Underwater Raiting	600m
Durability	🏺🏺🏺🏺
Price	﹩﹩﹩

Burns AquaMate

Burns Aquamate is a typical connector we use on the tether cable. It’s underwater rating, locking ring and it’s ability for WET mating makes it an excellent candidate for this application. The rubberised core is extremely durable and water tight, while the tips of the conector remain flexible and can handle a lot of abuse

Installation Difficulty	🧩 🧩 🧩 🧩
Max Wire Load	40A
Pin Count	2-18
Wet & Dry Mating	✅
Underwater Raiting	600m
Durability	🏺🏺🏺🏺
Price	﹩﹩﹩

SeaCon

The SeaCon is the best the industry can offer in terms of durability and longevity. Offers both dry and wet mating and a locking ring for extra security. With proper cable stress relief, the SeaCon can be a load bearing joint. When not in use, the connector can be capped with a whip cap. One drawback is that it is expensive for your typical DIY project. A good practice is to keep the mating part of the connector covered in silicon grease.

Installation Difficulty	🧩 🧩 🧩 🧩
Max Wire Load	40A
Pin Count	2-16
Wet & Dry Mating	✅
Underwater Raiting	600m
Durability	🏺🏺🏺🏺🏺
Price	﹩﹩﹩﹩﹩

Binder 770

This connector provides a low profile, almost flush socket as well as good pin protection when unmated. The drawback is that this connector is NOT water-rated and is meant for on shore connectivity like the tether cable to the shore station. Provides a solid locking connection but can be easily damaged if subjected to side force application.

Installation Difficulty	🧩 🧩 🧩
Max Wire Load	40A
Pin Count	2-16
Wet & Dry Mating	NO
Underwater Rating	NONE
Durability	🏺🏺🏺
Price	﹩﹩﹩

Back of an Blue ROV Electronics Enclosure With Connectors

In this example you can see a combination of different penetrators and connectors on a typical BlueROV2 build by FieldWerx. Tether is terminated with Burns aquamate 8 pin connector for ease of transportation where every pin corresponds to an ethernet lead. Additional Cerulean sensors are USB connected using BlueTrail Cobalt series 8 pin connector.

As USB uses only 4 pins, additional pins can be utilized for different protocols such as I2C, CAN or PWM. This allows use of different sensors and accessories easily swappable throughout the course of a single mission. Adding versatility to your setup and saving up to 4 bulkhead holes for other purposes. This is just one of the examples how choosing your connector accordingly can benefit your ROV experience.