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Summary: Sailboat hulls are great-on sailboats! Sails and rig make a sailboat stable, but not only does a trawler with a sailboat hull have deeper draft (see Lesson Two) but it will wallow in one-foot seas. That’s why some builders push expensive stabilization gear, which is practically guaranteed to fail when needed most. Instead, we at Mirage Manufacturing asked naval architect Lou Codega to design an inherently stable, true displacement hull.
Mirage Manufacturing’s philosophy on trawler hull design
By Lou Codega
Naval Architect
I continually read of builders and colleagues touting what they perceive to be the optimum hull for all conditions, having exactly the right blend of this quality and that aspect and this pedigree to make their hull the best choice for everyone under all conditions.
That’s frankly a bunch of hogwash and does you, our customers, a great disservice. The life of today’s trawler yacht is just too varied to make one hull form the best for everyone at all times.
In fact, no other aspect of naval architecture (See Lou Codega’s Curriculum Vitae) requires so much compromise as does the design of the hull itself, and the optimum hull just doesn’t exist. The obvious solution is to anticipate how potential owners are going to enjoy their boats, and to design the best hull form for that spectrum of uses. We have anticipated living aboard for extended periods, even permanently and often independently in remote areas, with the comfort of a shore-side condo; typically crewed by two; exploring coastal areas or making annual migrations along the waterway; offshore trips when the urge strikes, under conditions that are as controlled as can be expected, by which I mean that forecasts for the passage will keep the boat out of true storms.
And money was an object, not only in selling price but also in maintenance and operation. We think that we’ve designed a boat that does an admirable job of fulfilling these goals. If your desires match with our emphasis, then perhaps we’ve made a good match.
The Great Harbour hull feels right at home almost anywhere, derived as it was from modern workboat hulls, not sailboats. I think that this is appropriate because a workboat has to earn its keep and keep its crew safe 365 days a year. The boat is not light, and design displacement is nearly as high as any boat of comparable length to carry the anticipated weights. But we chose to take the volume afforded by the high displacement outward, rather than down. (See Lou Codega on stability)
This increases the usefulness of the accommodation space tremendously, allows for outstanding machinery access, and provides for cavernous storage spaces below deck. And the corresponding shoal draft opens up cruising grounds and anchorages that are inaccessible to her deeper draft sisters, to say nothing of removing much anxiety from waterway passages and inlet transits.
The hull has been shaped for continual economic operation at hull speed. You’ll see little of the squatting and none of the large increases in fuel consumption that occur when boats with ship-like hulls are pushed as hard. We’ve selected a twin engine machinery layout as it is a ideal match with the shallow draft hull, allowing as it does optimum propeller diameters to keep blades above the bottom of the hull, outstanding maneuverability and built in redundancy. Test results show that only 46 horsepower are required at hull speed. This is less than the rated power of one engine, and we can nearly reach hull speed on one engine, dragging a fixed propeller.
And we think that we’ve done well on the economic side, also. The boat is miserly in its consumption of fuel, and the generous tankage gives a lot of flexibility in choosing refueling sites. The same beam that gives you access for easy maintenance also allows her to be efficiently built. And it allows for fitting the desired accommodation into a shorter overall length, which will reduce dockage and maintenance expenses with very little penalty in performance
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