One of the reasons we like aluminum construction is that it is simple to build in extra factors of safety precisely where they are required. In this case, we are looking at the cutwater (bow stem) which is potentially the most vulnerable part of the boat. On our fiberglass designs we always add lots of extra laminate here. For work in ice and debris infested waters extra metal is the optimum answer.
The stem bar which forms the cutwater is a massive chunk of solid aluminum.
This is eight inches (200mm) in depth, 1.5 inches (40mm) thick,and extends deep into the forepeak. Note the bottom plating where it intersects with the stem bar. The bottom plate is 12mm (15/32″) thick. The hard edges will eventually be shaped and the area forward of the bottom plate filled with weld.
This area is backed inside the forepeak by a collision bulkhead, so that in the highly unlikely event of a beach of this area there is an additional layer of security. There is another watertight bulkhead between the forepeak and interior in addition to which there are two more partial and one full watertight bulkheads as you move aft in the interior.
Posted by Steve Dashew (October 17, 2009)
November 20th, 2009 at 8:07 pm
Is this major piece of aluminum cut asit appears, or has it been bent to shape?
does the leading edge get ground to make a smooth radius?
If I’m correct your boats are known for a very fine bow. how does this 1.5″ wide cutwater affect the hydrodynamics of the bow?
November 21st, 2009 at 6:06 pm
Hi David:
The bow center plate will get radiused. The width does affect the hull lines, but this is taken into account from the beginning and is part of the prismatic analysis. It is cut from flat plate.