Architectural Integrity

Design Tenets – Capability AND Liveability


Why is a Kadey-Krogen the trawler yacht of seasoned mariners? No doubt because Kadey-Krogen Yachts builds trawlers that combine globetrotting capability and at-home liveability. Some yachts are designed and built for the single-minded purpose of bluewater capability (often at the expense of creature comfort), while other yachts are built primarily for liveaboard comfort, never mind the dream voyage. Only a Kadey-Krogen yacht accomplishes both aims better than any comparably sized yacht in the world.

True Architectural Integrity in Every Kadey-Krogen Design


One of the most important yet often ignored marine design concepts is Architectural Integrity, which essentially means keeping a vessel true to its original design parameters. Naval architect James S. Krogen once said, “To produce a successful design, you must make an honest determination of how the vessel ‘really’ will be used and then prioritize every design decision to favor that outcome.” In the case of a Kadey-Krogen full displacement trawler yacht, that “outcome” is a sea kindly, live-aboard ocean crossing yacht.

James Krogen’s pronouncement has often been ignored and in the last few years we have seen notable manufacturers stretch a 41 footer to a 49 footer, a 47 footer to a 52 footer, and a 55 footer to a 60 footer. This disturbing trend compromises the performance of the resulting hull design. Perhaps the best-known example of violating architectural integrity occurred back when SUVs first became all the rage. Manufacturers simply took the chassis of another vehicle and put a large boxy structure on top, thereby raising the center of gravity. Remember all those early stories about SUVs rolling over?


So why do manufacturers violate the architectural integrity of one hull design and stretch it to make another model? Simple. It’s a relatively low cost way to introduce another model, and with more models there is a greater chance a builder will have a vessel that appeals to a particular customer. Keeping costs down and building and selling more boats equate to greater profits.

Why not stretch a boat? To design a boat with optimal performance involves a mathematical formula where everything is a variable and the goal is optimal efficiency and stability. Like any formula, if you change some of the variables without changing others, you will get a different result. This is inescapable.


If you take a boat that was designed at 55 feet and “stretch” it to 60 feet, all of the engineering is changed. You simply can’t design the proper curvature and shape of a hull, stretch the middle by 10% or more or stick a larger cockpit on, and have the physics stay the same. You can’t determine, using sound naval architecture principles, where to place the propellers, rudders, etc. on a boat, and change its length by 10-15%, add a larger engine and prop, and then expect the same handling results. Like most bad ideas, this one tends to magnify itself. It’s hard enough to get a big heavy boat to turn, and in my example above for the first few moments when the rudder is turned, the boat’s going to try to push sideways until the reduced torque available finally starts the turn. This may result in just an unpleasant ride but at some sea state it will approach the line between difficult steering and being unsafe.