When playing Tide hunter am I considered a support?

Rushing blink dagger is generally the way to go on Tidehunter. You want to get blink after arcane boots as soon as you can, then refresher, pipe, mek, or force staff.

However, Tidehunter is rarely in a position to be farming away. Getting courier for your pub game team wouldn't hurt before the horn. Buy that, a (very valuable now that it is 3 armor) ring of protection, and tangoes, and you're good to soak up experience offlaning getting levels in your passive and your anchor smash to farm the ancients, where you can get 6, and the blink dagger will fall into place after using your ult somewhere.

Unless... you're buying all the team's smokes, wards, counter-wards, dust... especially if your level 6 gank or ancient stacking didn't go swimmingly. There should be someone, if not two other players, in your game, who are more apt to get wards throughout the game. So, short answer (at the end of a long answer): no, Tidehunter isn't a support role.

Dependent on the four people you end up in a game with, well, you might be delaying that dagger for some wards if no one else will.

Tidehunter is usually a position 3 or 4 (offlane or farming support). In the farm priority, depending on the composition of your team, you can be asked to build a mekansm or a pipe. However I would prioritize blink dagger over mekansm on Tidehunter in 95% of the game. There was a time where Tidehunter was played as a non farming support and was used only for Ravage but nothing else. At that time buying ward and courrier was natural. On the current patch (6.82) putting Tide in a 5th position is a waste of Tide's ability to contest any melee farmer and almost any dual lanes. His nuke (Anchor Smash) allows you to trade hit with anyone and since you get reduced damage from Kraken Shell, you can almost zone an enemy support out of his safelane if played correctly. Last but not least a farmed lategame tide offers often 2 Ravages that are most of the time gamebreaking and can win you the game.

Personnaly I would always rush a blink dagger because the initation potential it offers is huge. After that depending on how the game is developping (many early fights ?), or the ennemy team composition (lots of magical damage ? lots of chase potential ? Some hard right clicker ?) or if my team is domintating and creating space to get some farm, I'll concider the following items : Mekansm, Pipe of Insight, Heaven's Hallberd, Force Staff or Refresher Orb. In any case I like to get either Mana Boots or Tranquils + Soulring in order to sustain the Anchor Smash spam.

You can concider getting a Mekansm first if you or the ennemy team is foreseeing early mid game push (10/12 min). A Meksansm at that point will give your team a huge avantage for the early fights.

Tide can be played on any of the 5 positions , but as he excels at the offlane (due to kracken) and farming support or no.4 (he can farm quite well with anchor smash even the ancient stacks with new change) he is played in these two positions more often. Simply tide with damage items or tide not having blink arcanes after 20 mins in to game just doesnt contibute well in team fights for a positive outcome for his team. Personally when you play tide , look at your team composition and try to analyse it before you buy items on him . If some other hero(1 or 2 ) can probably go for mekansm then you should rush blink or atleast arcanes-> blink . If you are the only hero that could get a faster mekansm than 4 or 5 then you should try to get it if you plan on pushing or you should just go blink. Though you feel mek is a waste on tide , if you have say 4 protect 1 type of heroes then going mek is really good as you will take 4 v 5 fights and a mek is gonna be more useful than a blink IMO. some games dont proceed as you like them to in pubs . your team is just doing very poorly and you also dint have best laning stage. I would suggest to go Urn arcanes and then blink when you are really behind , being greedy when behind is just adding to losing the game .