# Can Maxsurf (or Hydromax) calculate what angle boat will sit in water?

Discussion in 'Software' started by Michaelp, Apr 6, 2011.

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### MichaelpJunior Member

Hi,

I am new to this forum, and also fairly new to Maxsurf (so please bear with what may be very simple questions).

In Maxsurf (or Hydromax?), is there any way that I can calculate at what angle a particular boat design will sit in the water. If so, there must also be a way to input the complete mass of the boat and its center of gravity (or a place to input particular objects - ie an outbard motor - with its location and mass).

I understand the concept of displacement vs mass, but I think it is also important to know what angle a given vessel will sit at in the water.

Mike

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### bhnautikaSenior Member

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### MichaelpJunior Member

I have an idea about how to do this manually, could somebody please confirm with me if I am on the right track?

1) Calculate center of mass by using this formula { COM = ((o1xd1)+(o2xd2)+(o3xd3)...)/(o1+o2+o3) }
where:
COM = Center of Mass (as a distance from the reference point)
ox = object x mass
dx = object x distance from any constant reference point

2) Split up the boat into a number of sections (the more sections - the more accurate the result). Then manually calculate the displacement of each one of these sections, and note there distance from the same reference point as used in item (1) above.

3) Use same calculation used to calculate COM to calculate Center of Flotation (for lack of the correct term).

4) Compare Center of Flotation to Center of Mass. If they are at the same point, the boat is sitting at the correct angle in the water. If they are not, adjust the angle the boat is sitting in the water, maintaining the correct displacement. Then repeat steps 2-4.

I would appreciate any constructive criticism of the above idea....

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### MichaelpJunior Member

Thanks BHNautica, that webinar looks to be exactly what I need.

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### ekamarineJunior Member

Yes, hydromax will do that for you after the desired loadcase is defined. All you need to do is making an "equilibrium calculation".
or you can do it manually on an excel file which will take more time

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