Baetz was barely making way in light winds off the coast of Öland when the seal clambered on board his 28ft trimaran boat, the Flaneur.
At first the seal looked content and relaxed as it laid on the boat basking in the sunshine and getting a free ride. But the next day Baetz said it was still there and looking very lethargic and the yachtsman began to worry about the seal's state of health.
The MidsummerSail race committee were able to send Andre's video of the seal to a veterinarian at the Oceanarium in Stralsund. The vet gave the animal the all clear, saying seals were generally robust and shallow breathing was normal when resting.
At one point the seal slid off the boat in the sun only to dive under the trimaran twice and, cooled down, clamber back on board again.
The rules of the AgoraDirect MidsummerSail allow a change of crew, so technically the seal can continue sailing with Andre - but it is not allowed to paddle.