During an airing of ABC’s Shark Tank, our attention was drawn to a pitch on Episode 10, Season 11 when a video played of a man plunging himself into an ice hole. What was most intriguing was how quickly he claimed to recover from that bone-chilling experience.

​

The man taking the icy dip through a frozen lake hole wore apparel from Fortress Clothing®, a Utah-based company whose slogan is Warm to the Core™. Fortress Clothing describes itself as “… an outdoor clothing brand that keeps your core warm, even when you’re wet,” (https://fortressclothing.com/about/) and claims “we found a way to keep you warm even when wet” (https://www.youtube.com/watch?v=LeqeVFDRHyA). As divers, our immediate thought was if this clothing line had an application in the underwater environment.

 

The Fortress Clothing website focuses on outdoor enthusiasts, snow sport athletes, industrial workers, public safety, military personnel & preppers. What about the diving sector? We reached out to the company and corresponded with Dale Lewis, President of Fortress All Weather Gear. According to Dale, the company has a number of drysuit divers using Classic (½-inch insulation) Fortress Clothing apparel as undergarments and have reported “great success.” We had to find out for ourselves.

 

Without much delay, our first Fortress apparel arrived. For our first boat dive outing, we tried the Base Pro 1/4 Zip as a surface interval warm-up top for the wetsuit diver and the Base Pro Crew as undergarment top for the drysuit diver.

 

For those not familiar with Southern California diving: It can be an uncomfortable experience, with ocean temperatures dipping into the low 50s in wintertime. Depending on air temperature, it is not unusual for there to be little respite from the cold. Scuba parkas provide little relief for wetsuit divers during surface intervals and dry suit undergarments are known to quickly become uncomfortable with the smallest of seal leaks.

 

Here are how are tests turned out:

 

Wetsuit Test

With water temperatures hovering at 57°F and air temperature in the mid-60s, warming up between dives with a wetsuit is usually a challenge. After exiting the water, our male divers stripped his 7/8 mm wetsuit down to the waist. The Base Pro 1/4 Zip was pulled on and it immediately began warming the chest, stomach, back, and arms. During the standard 60-minute surface interval, core temperatures returned to normal—which was a pleasantly unique experience. The only wish was to try out the Fortress gloves to make chilly hands warmer!

 

The collar design on the Base Pro 1/4 Zip makes it impractical for use under a wetsuit. The long sleeves defeat the internal dams built in the arms of most semidry wetsuits. A vest might make for a good insulating layer for wetsuit divers.

 

Drysuit Test

Used as the only undergarment top with the Waterproof D1 Hybrid, the Base Pro Crew proved to handle a leaky neck seal wonderfully. The outer portion of the top was wet to the touch, but the water wicked away from the inside leaving the diver dry and warm. She was not aware of the neck leak until after the dive when it was evident the outer portion of the top was wet.

 

On a second boat trip, the diver used the same configuration, but this time, a much larger slug of water—about a cup—entered the neck seal. The diver felt the water enter her drysuit but her skin stayed dry throughout the dive. This is not like most drysuit undergarments that get wet and cold with any type of leak.

Other characteristics:

 

Buoyancy & Fit

Fortress Clothing items have slight positive buoyancy. When fully saturated, the Base Pro Crew floated at the surface of a freshwater pool. Adding one pound caused the top to sink. As a drysuit undergarment, the diver added one pound to her weights to compensate for the Base Pro Crew buoyant characteristics in ocean water.

​

The Fortress apparel sizing chart was accurate for us. Drysuits like the Waterproof D-1 are loose-fitting and less-snug undergarments work acceptably, but if you wear a neoprene drysuit, you might want to consider going a size smaller in tops to ensure a snug fit under an equally snug overgarment.

 

Next Tests

1. In cold water (<60°F): Wear the Classic Vest under a wetsuit to see if the vest enhances core warmth retention and/or shortens surface interval recovery time.

2. In tepid water (~75°F): Wear the Classic Vest over a long sleeve rash guard (no wetsuit) to determine if the vest enhances core warmth retention and/or shortens surface interval recovery time.