? is it the same as mine ? If so, the wood around the inside has some screws, plugs and varnish over, but they do come out without damaging the surrounding teak if you are careful and patient. Then the wood can be pried away from the wall and the sliding window, in its track, can be removed. Before you start, get some new track, both the kind that goes on the bottom and the kind for the top and sides. The velvety fabric inside the tracks will have rotted away by now, so it is a good time to replace the whole works. Also, while you have it out, inspect and repair the sill if necessary. This is the most frequent source of leaks on boats of this vintage.