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Old 04-17-2016, 04:00 PM   #8
waddenkruiser
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City: Southern Baltic
Vessel Name: Sømarken
Vessel Model: AMS 40'
Join Date: Jul 2012
Posts: 188
Quote:
Originally Posted by sdowney717 View Post
Of what advantage are these shaft tunnel extensions?
I raised the same question to the designer and former owner of AMS (he is in the 70s and has retired some years ago). His answer: Just for the ease of cleaning the hull from mussels.

These tubes are just an outside extension, not directly connected to the inside part of the shaft tunnels or stern tubes but "stuck" on the hull. He imposed them to avoid the larger elliptical "mouth" in the hull which results from the angle at which the shaft leaves the hull. He made the experience that inside of the elliptic breakthrough a lot of mussels are accumulating over the time ...
I'm an engineer and from a fluid mechanics perspective these extensions are looking sound and reasonable. Therefore I decided to keep and rebuild them (cutting them off and live with the elliptical "mouth" and invest every three years some time to get the mussels out there would have been an acceptable option) - although there positive effects may be neglected in the speed range we are under way.




best regards / med venlig hilsen
wadden
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best regards / med venlig hilsen
Wadden
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