Lithium based soap grease

Lithium based grease can be of different viscocity (thickness). The marine grease you are using may well be a lithium based product, and it should list on the packaging the base component.

Lithium is "simple soap" base and is a good choice for multiple purpose. It holds up very well against shear and also resists water washout. It also is great for keeping the oil suspended in the base soap.
A lithium base grease can also be a "complex soap" grease when other components are added to the package, but for our uses it's not usually warranted to use complex base greases.

"Inorganic" greases are ones that use metalic thickeners graphite, carbon black, or molybdenum disulfide. They are good for some applications, and if your manual calls for a moly grease specifically, use one.

I always steer folks away from "Organic" type greases. It is possible for the base to harden like a rock when the oil sperates from the base of an organic grease. This could be bad news for a bearing that got neglected for any period of time. These type greases will list polyurea, polyethelene, polypropelene, etc...(any sort of poly).

*Rule of thumb is that frequency of application is more important than type of grease used.