Hydrostatic release with a composite plunger assembly

A hydrostatically releasable coupling assembly for releasably securing a buoyant object to a vessel with a lashing strap, said coupling assembly comprising:

• first and second lashing plates;
• cooperative latching means carried by said lashing plates for releasably coupling said lashing plates together, said latching means being movable between an engaged position for securing said lashing plates together and a disengaged position for release of said lashing plates;
• and
• one of said lashing plates including a plunger assembly having a plunger body defining a first diameter portion, a plastic collar mounted to said plunger body defining a second diameter portion, and an intermediate metal portion proximate said plastic collar, said plunger assembly being movable between a locking position with said second diameter portion retaining said latching means in said engaged position and a release position with said first diameter portion positioned for movement of said latching means from said engaged position to said disengaged position;
• said latching means and said metal portion being shaped and positioned such that when said plunger assembly is in said locking position, said metal portion is spaced from said latching means, said metal portion substantially minimizing contact between said latching assembly and said plastic collar when said latching means is moved from said engaged position to said disengaged position.