Until now, we have been using a long metal pole jammed up between the underneath wooden trim piece on the companionway hatch opening and the back of the sliding top to basically lock ourselves in at night and keep someone from opening the hatch. The bonus is that the pole is also an handle for our emergency Oh Shit hand bilge pump thus making a long handle that allows for proper Oh Shit pumping/bailing of unwanted water. Have you seen the standard handles? They are no longer than 12 inches long. Given the placement of most Oh Shit pumps, that does not work well at all.
Above is our handle for the emercency Oh Shit bilge pump. Below is the standard handle. Which would you rather operate for a couple of hours?......hopefully it's only a couple of hours or less!