Rayleigh was sitting on the rock; his legs cross, explaining his idea to Luka. He barely had gotten to this island, by swimming of course (like a normal person) to the island. Rayleigh was preparing to train Luka for two years since she was still weak.
Luka knew it all too well, that she was weak. She couldn't even save her crew; they all disappeared before her very own eyes. It hit Luka, which she needs to grow stronger. What type of captain was she if she couldn't save her crew, which was counting on her? All Luka could do was stand and watch, as each of her crew members, nakamas, were taken away from her. She was too weak if she couldn't even save one of her nakama, not even the littlest, Chopper was saved.
Luka was glad that she could save her brother, but she still lost her crew. They all could return to her, but is she strong enough to save them, if that happens again? The answer was no, she wouldn't even be able to punch Kuma, who was the cause of her separated crew. Luka didn't want to experience that again, that hopeless feeling of seeing everyone disappearing. It greatly reminded Luka of that one island with the huge Lilly, it was absorbing her friends away.
Those were the reason that Luka accepted Rayleigh's plan, it was to help for comrades. He would train her in Haki, for two years on a Weatherly Island, next to Amazon Lilly. They would train while her separated crew would do the same, each growing in their skills.
The plan was for Luka to have a symbol of '3D' crossed out and '2Y' underneath it. Luka would go back to the battlegrounds and ring the Ox Bell 16 times (much like the golden bell on Sky Island), where the journalist would take pictures, showing the symbol. The symbol would be in the newspapers, where all of her friends can see it. It would be a message for all of her friends, hopefully they would understand it. It was a promise to regroup within two years, to train and become stronger than before.
After the plan was in action, Jinbe headed back to his home, under the sea. Rayleigh trained with Luka for the next two years, in Haki. While her crew trained in their different skill sets: cooking, navigating, swordsmanship, shooting, etc.
Yeah I'm heading off the path of ShanksxLuka but since I changed the story a bit, I needed to change it back. Luka will ride with Shanks on his boat, when it's time to return, that way there will be moments between them. You know, it's been 11 chapters since they departed/engage each other, so I'm going to add a lot of moments of them together while on his boat. Where should they official get marry or met again? I'm thinking that after the boat ride, I might just go to their wedding (blowing off the story all together).