Now, in the Age of Water, there are remnants of that people: metals that have begun to rust or deteriorate, plastics that are stuck in whatever shape they are found in, rare findings of solar panels that still generate electricity, old rigs that used to drill into the land below the water that no longer run, parts of old turbines that generated electricity.
The ability to manufacture these things has been lost for the most part. Most of the world's current technology is based on the ability to salvage, repair, and replace. Those who have worked out a system for working metals and plastics are considered highly valuable individuals, often connected directly to mercenaries and merchants.
Ships are made exclusively of metal, fiberglass, poly-carbonates, glass, and plastics. The majority of ships are small, six or seven person crews at the maximum. Likewise, harbors are small and built close together so that perhaps ten households are contained within any given harbor. Collectives are made up of anywhere between three and fifteen harbors.
There is only a handful of ship makers left in the world, and three of them are strictly salvagers. These three salvagers are well-known and well traded with, but their prices are steep and their attitudes cut-throat. People know that others exist because they have seen new ships with different markings on them, but the whereabouts are unknown or well-protected.
Harbors are also constructed of the same materials. Power is generated on harbors, for the most part, by wind turbines. However, it is common for one harbor in a collective to have the ability to generate any power at all. There are even a few collectives without any source of power. These collectives subsist largely on fishing and trading with independent merchants.
Solar panels exist but they are rare remnants of a past time. Most are broken and the few that work are hoarded by those with great power. In a lifetime, a person living in a harbor collective most likely will not have seen one. If they did, they are most likely dead now.
Wood and any wood product does not exist in this world. Likewise, textiles made from land plants and land animals do not exist. Sea plants can be dried and burned or turned into surfaces that can be written on with dyes and charcoal from the burned plants. Fabrics are made of woven twine made from sea plants for the most part. Leather can be made from the hide of whales and dolphins, but its consistency isn't good and the technology to make it better is too difficult to cultivate, so most don't bother.
Weaponry is made up of magic to manipulate the situation, sharp edges to cut, and blunt objects to bludgeon. Guns do not exist as gunpowder doesn't exist. Not to mention that developing it would be a hassle since magic is much more functional. Harbors have been known to use catapult technology, but this also is highly inefficient and laborious. Most people use magic as their first weapon and a sharp edge as their second. When ships are taken down, it is generally because the winning ship's Watcher was better than the losing ships, and the Pirate of the taken boat got his throat slit. Harbors generally defend themselves in a similar fashion, employing the use of Watchers and magic over anything physically fashioned.