Be careful
I have an '89 28.5 and went through replacing my anchor light recently. The problem was the replacement bulbs were convex instead of concave. I ended up just drilling a hole in the Z-spring that holds the bulb in place. The bulb's pointed ends fit in it nicely and the light works fine. Needless to say this took a several trips up the mast to get all this done. In defense of West Marine and their parts catalog, the anchor light may not have been the original and not the correct one. At any rate, the bulbs are cheap so you may want to get both style bulbs, concave and convex, to save you some trouble. You can always take the others back. The model I used was less than 1 amp.