I want to buy a telescope. Ideally with rangefinder and/or internal compass bearing. Possibly also image intensifier. I have a 'lazy' eye which makes binoculars irritating to use. Any recommended makes/models
I too have double-vision at times, but binoculars are much easier to hold on a boat, and some are stabilised. For shore use they sell a good range at Essex wildlife centres, but not with the extras you are asking for.
Get a bird watcher's spotter scope. They are effectively half of a decent pair of binoculars. Aldi had them a couple of months ago for about £20 - will cost you 5x that for a "normal" one. Ideally, you want 7x magnification and 50mm object lens like good marine bins, don't exceed 10x as you will not be able to hold them still.
The pistol grip idea is excellent, you will get that from any camera shop and it will fit the tripod fitting in the base.
I would feel tempted to go along with the idea of using a binocular with the lens cap on one side. That way you will have a decent binocular for others to use and something which may be easier to hold.
If you are tempted to buy a telescope be warned that the prismatic type that are just like one half of a prismatc binocular are difficult to aim! At least I find mine so.
The usual difference between a telesocpe and a binocular is the magnification. Telescopes tend to be more powerful and less useful on a boat. A night-vision instrument wont work in daylight. You can get a monocular which is really a low power telescope or half a bino but I don't know of one with a rangefinder. Have to agree with what has already been advised - get a Helios Oceanmaster 7x50 water proof bino with rangefinder and compass for £98 and leave one lens cap in place.
I have one eye (left) and although I've tried many times, I can't get on with telescopes. I use various binoculars with too many problems. If you go for a pair which gives a bearing, as one pair of mine does, ensure it is in the correct side! My bother has a pair with it in the wrong side, for me, and I find them difficult to use. I would not remove the side not being used as I find holding them with two hands is the best way on all but the smallest type. Also they are then available to crew members if required.
Allan