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COMPARING features of the Waters Mark l CF wingmast with the Mark ll model
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QUESTION: I am very interested in your Waters Wingmast, but see there is now a Mk.l and a Mk.ll for different range of sizes. As I need a mast that is on the border line between the ranges indicated for the two models, can you please elaborate on the differences, pros & cons etc, and whether one can upgrade from a Mk.l to say a Mk.ll without buying a 2nd manual. Thanks Mike. Evan-Mc, CA
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ANSWER: Sure, and thanks for your interest in this unique way of getting a very efficient wingmast ..... by home-building. It IS different work and it does take time, but no more difficult than other boatbuilding tasks … and the result can be extremely rewarding. Both manuals are very detailed and you should find all the help you need contained there …. and there are also now others who have succeeded who may be accessible for further advice and encouragement. Although the construction concept is basically the same for both designs (a CF shell built around a central web), there are a few differences that may be important to you so worth understanding.
First, the Mk.l has a rounded nose with a diameter of about 80% of the mast width. For moderate sized wingmasts, this gives a section that is less critical re the exact rotation angle due to less risk of stalling. However, as masts get bigger, this nose diameter starts to get quite large, adding to its general air resistance. So when it gets close to about 80mm diameter, it was decided to amend the mast section so that the nose would not exceed that nominal value and this results in a more elliptical section where the nose diameter may vary from 50-70% of the mast width. While this looks on paper to be even more elegant and aerodynamic, it does require more care to tune its rotation for the best efficiency, requiring that the mast axis point into the apparent wind within a reduced (tighter) range compared to that of the Mk.l round nose model. IF that is done, then the Mk.ll can theoretically be slightly more efficient. If not, it will stall and then will almost certainly be less efficient.
With the larger sizes of the Mk.ll model also comes some changes to details.
This PDF defines what the important ones are (with photos). List of Differences.PDF
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