Indeed, thanks for that. I didn't think of that example of an exception to the rule
: some marine equipment has the "rolling element bearings" (fancy generic covering ball, needle, cylindrical roller, taper roller, spherical barrel roller, etc...) integrated with the design.
By that I mean that one or both raceways is part of the equipment, rather than being a separate ring you get when you buy the equipment. This goes right back to pushbike steering
stems and pedal cranks, over a hundred years ago, and loose bearing balls are still sold as 'cycle balls'.
Ball and roller bearing blocks are the most obvious example in the marine sphere where there is no separate 'bearing' as such, but as Wotname points out, winches also generally use needle roller and cage assemblies which are proprietary to the winch
manufucturer, ie designed and built in-house, and which use the adjacent surfaces of the compenents as raceways.
Incidentally this is particularly straighforward for needle rollers, where these are simple cylindrical surfaces.
The reasons as I see them are that firstly there is no need for the precision you typically get when you buy an off-the-shelf rolling element bearing, secondly there is a strong need to save space in the radial direction, and thirdly the material selection is crucial when the "lubricant" is seawater. Conventional bearing steels, while high in chromium, are far from "stainless". And stainless off-the-shelf bearings are horribly expensive, available only in limited sizes (mostly the very small ones) and will not carry the same loads.
gears sometimes use "off the shelf", non-stainless bearings, to which the slightest exposure to seawater is a virtual death sentence. They seal them so that, in theory, seawater cannot get to them.
I've had mixed experiences with these on other people's boats, but it has always seemed to me such a bad idea that I would never dream of owning such a piece of equipment.
As a general rule
of thumb for designing above-decks marine equipment, the situation eventually arises where the crowning achievement of seals is to stop water
getting back out once it has got in.
This gets closer to the truth the closer you get to the bow.