This Chelsea ships bell dates to about 1900 according to serial number dating.  The clock was in good condition and appeared to have recent servicing, but did not strike the half hour reliably.  For those of you (and I was one) who are not familiar with a ships bell, it does not strike the hours in the normal sense. The clock is designed to strike up to "four bells" the end of the traditional sailors watch. So a properly working ships bell sounds one bell, which sounds like "ding, ding" at 4, 8 and 12. it will then add a half bell "ding" at the half hour. At the next hour it will sound two bells "ding, ding...ding, ding" and so on until it reaches a full four bells, ending the sailors watch. In this manner the sailor knows where his watch is without benefit of looking at a clock. In my inspection I found the lift spring for the half hour strike was cracked, not holding the lock in place all the time. Since no replacement part was available commercially, I made a new one out of a strip of brass, see photos.