Abstract: An underwater mobile observatory system comprising an aquarium able to hold water and large enough to support fish, coral, and to display artificial objects such as shipwrecks and ruins, a vehicle track extending through the aquarium the track generally being adjacent the bottom of the aquarium, the track having a portion which rises to a loading/unloading position, and a passenger vehicle coupled to the track for movement therealong and unable to leave the track such that changes in inclination of the track causes the vehicle to move up and down through water in the aquarium, the passenger vehicle having a main body portion to seat passengers and which is capable of being submerged, and a top portion which is open to the air, the spacing between the track and the water level being controlled such that water does not pass over the top portion.

Abstract: The present invention relates to a hitching device designed to be used to detachably connect two vehicles together. The hitching mechanism includes two jaws which may pivot with respect to one another in a controlled manner by virtue of intermeshing gearing therebetween. The ends of the jaws have a complimentary tongue and groove connection to facilitate resistance of forces which would tend to separate the jaws in the absence thereof. A lock block is provided to control locking and unlocking of the jaws, while a safety pin is provided to protect against undesired jaw movements.