here's some of my thoughts (which aren't worth 2 cents mind you):

• great start!
• biggest item i think is that it feels like total homebrew. I much more enjoy supplements that stay as true to 5e as possible, while weaving in legacy rules for topics that just aren't covered in 5e...and then filling in gaps with homebrew.  that way the document works for everyone, not just people willing to wholesale adopt someone else's homebrew into their campaign, requiring official rules to be set aside.
• weapons - add crew per weapon.  (fyi, when you look at existing ship weapons you'll see the ship stats imply huge discrepancies in crew/weapon...from like 1 to 5).
• i'd separate your equipment list into weapons and ship upgrades
• it would funner if your living loot satchel connected to a buried chest, not the ship's vault....somewhere out in the world marked by an 'x' on a map, which also adds adventure hook potential.  (also, a ship's vault should probably be an upgrade anyway - most wouldn't have one...maybe just a false wall or floorboard hiding a cubby hole at most).
• you keep talking about bosun's tools, but don't say what they are.  just rename to carpenter's tools, that way you're not needlessly inventing something new. (also, i don't think there's a master bosun...the position is just bosun)
• i don't like your default approach to sails..they're the most unprotected part of the ship, not the most protected.  sure, you can upgrade to fancy sails, but not all ships have flame-proof near-indestructible sails.
• if you want this to be a solid source which expands on existing rules vs replaces them...to my first point, i'd read Ghost's of Saltmarsh and go paragraph by paragraph over all the ships rules/stats/features and see if you have the topic incorporated...if not, ask yourself specifically why you're excluding it or why its different   (deviating off of 5e rules should be a conscious decision - an example here is your rowboat...its a simple object given the subject, just conform it (and all the other ships with declared stats) to 5e...and then reconcile your new ships to the existing ones.
• i'd get ahold of the 2nd edition 'of ships and seas' and see what in there you can bring up to 5e and incorporate.
• watch Master and Commander (watch it again if you've already seen it) with a notebook and see what's in that movie that you can use.
• you could also consider looking at some of the more popular homebrew sailing docs on dmsguild and see what they have that you don't....or how they're treating the topic differently.  not that you need to use any of it, but its sometimes a source for ideas.  although when I do this there usually isn't much - but i do find the occasional gem idea.

again, just my opinion

side note, if you're looking for art - here's a DMSGuild creator content character...was originally a drow but i changed her to a water genasi (changed her skin to blue and armor a seaweed green, changed the crown from a spider to a Spell Gem (Lapis Lazuli), and calling her outfit fishnet instead of spiderweb)...feel free to use if you publish on dmsguild (only, as the pic is only licensed to be published on dmsguild) for a badarse first mate / bosun / whoever.

https://1.bp.blogspot.com/-I_XkKsCmf7Y/Xv9qLJB3VwI/AAAAAAAAB9U/oYws_k4CQM8d7ap7sEk2Gj7euKAre4LswCLcBGAsYHQ/s1600/genasi.png

Thanks for all your feedback! Looks like I have some reading to do! Would you mind clarifying one of your points?
you wrote:
"weapons - add crew per weapon.  (fyi, when you look at existing ship weapons you'll see the ship stats imply huge discrepancies in crew/weapon...from like 1 to 5)."

Maybe I'm not reading it right, but I'm having trouble parsing what you mean.

Also: very cool water genasi art! 

Quote from munkey_ninja18 >>

Thanks for all your feedback! Looks like I have some reading to do! Would you mind clarifying one of your points?
you wrote:
"weapons - add crew per weapon.  (fyi, when you look at existing ship weapons you'll see the ship stats imply huge discrepancies in crew/weapon...from like 1 to 5)."

Maybe I'm not reading it right, but I'm having trouble parsing what you mean.

Also: very cool water genasi art! 

just answering how many crew members you need to use that weapon (so if I want to upgrade my ship with an additional ballista, how many crew do i have to add).  if you look at the existing ships in Ghost of Saltmarsh and try to back into how many crew it takes per weapon, the numbers are all over the place...below is a summary of available actions for various official 5e ships:

 galley

1. with 80 crew: fire 4 ballistas, fire 2 mangonels, AND move.
2. with <40 crew: you can do 2 of those 3.
3. with <20 crew: you can do 1 of those 3.
4. with <3 crew: can't do anything.

Lets forget about the first bullet assuming that 80 crew capacity is max and includes the deck swabber and all its assistants. Just comparing bullets 2 and 3, you're removing 4 ballista or 2 mangonels when you drop your crew by 20. ...which implies you need 5 crew per ballista and 10 per mangonel. The last bullet is also extraextra broken, because its basically saying you can man 4 ballistas with only 3 crew members on board- the rule is over-simplified to the point of being silly (imo, the easiest fix is to significantly increase that minimum 3 crew cutoff).

sailing ship

1. with 30 crew: fire 1 ballista, fire 1 mangonel, AND move.
2. < 20 crew: do two of those.
3. < 10 crew, do 1 of those
4. <3 crew, do nothing

So here it suggests 10 crew per ballista and 10 per mangonel.

A warship its 5 per ballista. For a keelboat, it's only 2 people per ballista.