mid-late 18th C Mariners - Clothing

[Silent Invader]

…

[Aaron]

I don't think other ranks had any sort of uniform until the mid 1800s. I'm no expert, but I do know you are safe for F&I and AWI for sure.

[Plynkes]

Captains would often outfit the crew of his personal barge in a uniform at his own expense, but other than that there was no uniform. But sailors did dress in a particular fashion. Often barefoot, and white cotton duck trousers, dark blue jackets, stripey shirts, and long pigtails were all common. Kind of like pirates, but without the flamboyance gained by stealing the fancy clothes from every passing ship you happen upon.

[Hammers]

Captains would often outfit the crew of his personal barge in a uniform at his own expense, but other than that there was no uniform. But sailors did dress in a particular fashion. Often barefoot, and white cotton duck trousers, dark blue jackets, stripey shirts, and long pigtails were all common. Kind of like pirates, but without the flamboyance gained by stealing the fancy clothes from every passing ship you happen upon.

Black painted boater or sennet hats.

[Plynkes]

Black painted boater or sennet hats.

Tarred black in northern climes, left the bare straw colour in the tropics (no idea why, though).

[Hammers]

Tarred black in northern climes.

Lest it rot on their heads, perhaps.

[Plynkes]

Is this where 'Jack Tar' comes from?

Could be, among other things. In the interest of waterproofing they tarred their hats, clothes, cables and ropes, and just about anything else in sight. They also tarred their pigtails too, but I'm not sure why, as hair doesn't really need waterproofing. They certainly liked tarring things, that's for sure. 

As to the tropics, I don't know. You'd think you'd need to protect things from rotting in the humid, damp air even more, but it could be because of the reasons already outlined.

[Mephysto]

Master Plynkes already answered the question quite well, I know, but if you like, I might add not so bad an article about the matter (although regarding a slightly earlier period, the general tone did not change and may well be considered valid for fifty-something years later) myself.

[warrenpeace]

Old Glory has a pack of "European sailors" in its pirate line that might be useful to you, Silent Invader.

[former user]

only thing I remember is short double breasted dark jackets and the straw hats.
shawls and scarves too

Not sure about barefoot apart from the appropriate weather
horizontally striped shirts is of course standard, even if not authentic

[Darkoath]

I wonder if the straw sennet hats were not tarred in the warmer climes so that it would allow air through to cool the head?

Foundry makes an excellent pack of british sailors and a pack of marines too!
There are also a couple of poses in the pirates range too that have sennet hats that would work nicely.

Darkoath