Help translating

Sorry to repeat this here, wasnt sure if it was in right forum and had no replys, so thought id re-post here:

I have been tasked by someone to create two runic phrases for a shield. the two he would like to create in runes are:

'Between the Devil and the deep sea'

'Three sheets to the wind'

both sea themed phrases, which i originally intended to simply translate into eldar futhark, so then i thought well i probably need to spell them phonetically first, then i thought maybe i should take it further, firstly is the 'devil' appropriate? as the devil in this sense doesnt exist in norse mythology, is there something more appropriate, perhaps between 'Hel' and the deep sea? also i thought i may be better trying to translate it to old norse then to runes correctly.

my first attempt was simply using a english/old norse dictionary i found online:

meðal hel eða djúpr haf

which i THINK says: between hel and deep sea

i had a chocie of words for sea, but coming from shetland haf was very appropriate as we call the old fishing grounds the far haff.

no idea what to do for 'the' so i just left it out, also not sure if it is constucted in the correct order.

another attempt for three sheets to the wind:

sheets being ropes, i used ropes instead and translated: three ropes to wind to:

þrir tengsl til veðr

Another important question i need to know - if i am translating these to eldar futhark, so i use 'F' for 'V'? and 'þ' for 'ð'?