Sargasso

The sounding line started to dredge up seaweed days ago, but now before you stretches a doleful sight.

d4	You can clearly see several derelict ships, but skirting the edges...
1	may prove tricky, as the powerful gyre seems to draw your ship nearer and nearer the mass of vegetation
2	you spy a recently ensnared arrival: a pirate, vessel-of-the-line, or rival adventuring company
3	is a scavenging vessel called The Disappointment, who may see your ship as easier pickings
4	rival factions battle for territory or looting rights - the losing side calls for your aid, promising plunder gleaned from abandoned galleons

d6	Should your ship approach too close...
1	strangling, leafy runners will rapidly begin climbing the hull, taking only moments to reach the decks. Like kudzu, if left alone, soon all you will see is a slick, leafy-green, vaguely-ship-like shape
2	the helmsman is likely to become distracted by air thick with mind-clouding spores
3	you may draw the attention of the primary resident: a Druid obsessively collecting sea-going vessels for some mysterious purpose
4	you are likely to be overrun with a tangle of aquatic shambling mounds
5	seal-lonely sailors are likely to desert without a second thought when beckoned by the numerous Kelp Dryads who make their home here
6	you will spy curious figures peering nervously out from the wrecks

d8	Marvelous treasures may await within, such as...
1	a floating garrison, mired here on its way to reinforce a forgotten war. Full of weaponry, some of which may prove magical
2	an Immovable Anchor, dwarf-made, the command word translates to a curse
3	a very special Sleuthing Spyglass, a stubby switch on the side can be depressed to show past events at sea
4	the pirate ship Patience, its hold laden with plunder from yuan-ti ruins
5	a barnacle-encrusted Apparatus of Kwalish, containing a small spell library
6	the sacred bones of Saint Luchet the Scapegoat, each piece of his skeleton is a valuable and highly portable holy relic
7	the golden Godship of Olifrax the Ungenerous. The entire hull glimmers in the sun. It's only gold leaf, but enough could be scraped off with a week's work to lease a small armada
8	a king's ransom, along with the True King in arcane stasis below deck. How will the kingdom react when they discover they've been ruled by a double-walker for the past two decades?