it's sailing.
Sailing is an unreleased and unconfirmed skill that is one of the most speculated about unreleased skills in RuneScape.
Many players believed that the new skill of 2009 would be Sailing, although a Jagex mod confirmed the new skill was not Sailing. Via in-game chat, Mod MMG (Mark Gerhard, Jagex CEO) said "no it will not be sailing unless of course I get sacked first

" However, during a live Q&A session on the RuneScape Forums on 6 August 2009 (Quick Find Code 13-14-674-59348769), a player had asked: "In your CC you allegedly said that Sailing will not become a skill while you're CEO, true?" Gerhard replied by saying: "I was only joking around about sailing, maybe there will be sailing maybe there won't be?", followed by a winking emoticon. This implies that Sailing could possibly be a future skill.
This apparent uncertainty was rebuffed again in the Q&A on 10 September 2009, when Mod Mark (not Mark Gerhard) said of the planned new skill: "Honestly, it’s not the Sailing skill. That was a crazy rumour based on a picture of a mage on a dock, who apparently is sailing a ship. He isn’t, and there is no Sailing skill. ... Oh, and the new skill is far better than sailing." Mod Fetzki added: "We couldn’t believe it when we saw the fake Sailing icon that someone had put on to the highscore list, but the community identified it as a fake very quickly."[1]
Contents
[show]
* 1 Evidence
o 1.1 Hiscores image

^ Real screen shot
o 1.2 RuneScape Header picture
o 1.3 Other

* 2 Gallery
* 3 References
edit Evidence
There has been lots of evidence put forward, although most of it is likely to be pure coincidence or fake.
Of the "evidence" that has been offered that does relate directly to in-game content, the following game features seem to have the most relevance:
* In The Tourist Trap quest, Captain Siad is found to have a book about sailing that is used to complete part of the quest. It is from this book that the icon for sailing used in the fake hiscores image is apparently derived.
* In the Dragon Slayer quest, players are able to purchase the Lady Lumbridge and in the quest become its captain. While players do temporarily engage in actually sailing the ship (with the help of an NPC), this ship eventually runs aground on Crandor Isle and is no longer usable as a ship.
Certainly given the location of Cambridge, where the Jagex headquarters is located, the employees of Jagex are familiar with nautical lore and have included many other elements of a nautical nature into the game. Neither of the two quests mentioned above either need or develop sailing as anything other than a temporary plot element.