So this second marlin I would not let sink to the depths. No matter what. As it was way too difficult to fling it on to the raft on open water, so I swam with it to the nearest island. Bandaged myself. Crafted a repellent and got my raft back. At the beach I would wrestle the damn thing on a floorless middle section of my 3x3 raft. Set sail for home!
The thing weighed a ton. The raft would make negligible progress with either sail or motor. And worse, it would all the time turn around. Heading north was almost impossible. Then I tried lifting it - it worked! The sailing speed improved dramatically if I was holding the fish in the air.
I also discovered I could look at the compass while holding it. (What I couldn’t do while using rudder.) Putting the marlin down would steer the raft depending which side of the center part I lowered it on.
But alas, progress was far from straightforward. The raft would constantly change direction and it took me two real life hours to zigzag in a general northerly direction.
Then - a calamity. I smashed the fish too hard down and the whole raft flipped upside down. I still wouldn’t let go of the marlin and swam towards a shoreline. Bleeding - again. I patched myself up and went looking for the raft for another two real life hours. But it had despawned I guess.
Well. At least I had my marlin a bit closer to the base. I could already see the carrier in the distance.