Since you know your position, 50N 1W, may I suggest you either attempt to sail north in your life raft to England or just look about for other vessels!
I hope you have a PLB or EPIRB. Once you have alerted SAR with your narrow band PLB, a handheld VHF will provide broad band notification to those around you, should there be any. Better yet, that VHF should have Digital Selective Calling with an onboard GPS.
You are going wherever the wind and current takes you, so "navigating" isn't going to help you one tiny iota, except to pass the time.
My pre-GPS copy of Dutton's indicates that you shall never leave behind the sextant, nor a time piece, charts & etc. This advice is completely outdated of course.
A life RAFT isn't going anywhere you want it to go. Lifeboats ( https://en.m.wikipedia.org/wiki/File:Titanic_lifeboat.jpg
), even with oars, are well advised to stay near the wreckage so they are easier to find. Under the assumption that a Titanic lifeboat could sustain 1 knot, the current and winds are still going to move it about randomly. Going nowhere is an understatement.
PS, yes, your longitude will be approximately the GHA of the sun plus 90. All we need know is the current UTC, the GHA of the sun corresponding and a way to measure the sun's altitude. Pity you didn't take Dutton's advice and bring along all the equipment necessary to perform CN. Without it, your position will be perhaps within a degree. So SAR only has to search 3,600 square nautical miles for your 2 square meter raft.
I am at present afloat in my boat, in the eastern Atlantic. The forecast is bad. If I sink tonight, and make it into my liferaft, I will time the moment the rising sun lower limb reaches half a sun’s diameter above the horizon.
No have sextant, no have versines. My longitude will be sun GHA plus 90°.
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