Atlantic Crossing Gear

Drysuits
With average water temperatures around 4 or 5°C in August, any exposure to the water will be very hard on the body. Survival suits (aka drysuits) are required to be worn during the flight.
https://www.amazon.com/gp/product/B0074K36NC/

Dry bag
This bag will be packed with survival gear needed in the event of ditching in the water, including flare gun, PLB, handheld radio, lighters, survival rations, and Swiss Army knife
https://www.amazon.com/gp/product/B071Y32GPQ/

Flare gun
Required by Greenland to be carried by single engine planes
https://www.westmarine.com/buy/orion--12-gauge-high-performance-alerter-basic-4-flare-kit--8665804

PLB
Essential for assuring rescue can quickly locate your life raft. Broadcasts your GPS location to satellites via 406MHz
https://www.amazon.com/dp/B006JXY0CQ/

Life vests
Must be worn during flight over water. Set to manual mode so that it cannot inflate inside the airplane when water is coming in.
https://www.amazon.com/gp/product/B0032ALK36/

Lighters

Food rations
Protein bars, mixed nuts, and gatorade

Rope/cord

Handheld aviation radio
The Yaesu FTA-450L is a great radio and will come in handy as a backup in the plane as well as in the dry bag if we ditch
https://www.pilotmall.com/product/Yaesu-FTA-450L-COMM-ONLY-Li-Ion-Handheld-VHF-Transceiver/transceivers

Gas cans
Since fuel is purchased in drums, it helps to have couple gas cans on board in order to hold on to unused fuel
https://www.amazon.com/gp/product/B00DW4YLLK/

Drum pump
Drum pumps are not provided by airports that provide fuel in drums. This is a siphon pump which requires that the container to be filled is lower than the source container. Will probably have to use this to fill the 5 gallon gas cans and use them to transfer fuel to the plane
https://www.amazon.com/gp/product/B00APU2X2S/

Swiss Army knife

Lanyards

Life Raft
Survivability in cold water is very limited as shown here. A drysuit helps greatly but given that rescue could take a very long time to arrive, being out of the water and dry while waiting is essential.
https://www.starmarinedepot.com/revere-aero-life-raft-4-person-compact-with-canopy.html