Hello from Berlin, Germany

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Heimfried
newcomer
Posts: 3
Joined: Sat Nov 23, 2019 4:49 pm

Hello from Berlin, Germany

Post by Heimfried »

Hello everyone,

my name is Günter and I live in Berlin, Germany. Since 2017 I’m building a boat: Cabin-Katamaran 6.3 m (LOA), ply on frame, Bernd Kohler design “ECO62”. She will be driven by electric (outboard) motors, as far solar assisted as possible. I’m interested in measurements of some values like drag, power efficiency of propelling systems.

After I learned about boat hydrostatics I did a website to calculate some values of an example boat and visualize a bit of her behavior if loaded or loads are shifted.

Gruß, Günter

John Perry
AYRS Chairman
Posts: 71
Joined: Tue Nov 08, 2016 6:39 pm

Re: Hello from Berlin, Germany

Post by John Perry »

Welcome Günter, - look forward to hearing more about your boat building project and perhaps seeing some pictures. I have not been to Berlin but I understand that there are many navigable rivers, canals and lakes in the area and I imagine that these would be ideal for leasurely exploration with a mobile houseboat such as you are building. Your website sounds interesting, do you have a URL to share?

I guess that the 'ECO62', if powered by low powered electric outboard(s) will operate as a 'displacement hull' with most of the drag being skin friction which does make the drag relatively easy to calculate by traditional methods - as you probably know the Michlet software is one way to do this using the 'ITCC line' as the basis for determining a skin friction coefficient. Electric propulsion with solar panels, and presumably a battery (mabe LiFePO4 ?) for when the sun is not shining seems to make sense for your kind of project and I see that the design has a large rectangular flat roof which looks to be ideal for mounting an array of solar pannels. I recall that some years ago I saw a similar plywood houseboat design at the Beale Park boat show and this actually used pedal power with two sets of pedals, another possiblity, at least for auxiliary propulsion.

Heimfried
newcomer
Posts: 3
Joined: Sat Nov 23, 2019 4:49 pm

Re: Hello from Berlin, Germany

Post by Heimfried »

Hello John,
thank you for your welcome. Regarding my boat building project: I was starting in a former garage which was just large enough to allow the build of one semi hull at a time. So I had to erect a tent (4 m by 8 m) in my garden to accomodate the further assembling of the boat. I'm reporting about progress, experiences and thoughts in this thread https://www.boote-forum.de/showthread.p ... ost4995890. Sorry, it's in German and very long, but you will find a lot of pictures, which could cause questions that I would appreciate. Last autumn we (many helpers and me) were flipping the brigde deck unit with the semi hulls and now I'm building the cabin.

Regarding my hydrostatics website the URL is http://www.bootsphysik.de/. Top right you will find a button "English". A lot of buttons marked "i" can be clickes to display information. The displayed graphs are simple but the math is not. Unfortunately there is at moment only one hull to play with. It is because a description of a hull consitsts of about 90,000 numbers (array).

The pedal drivben plywood house boat you have seen could have been a design of the late Phil Thiel (Seattle). His plans (Escargot, FriendShip, Ark) are in my desk also.

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