Help on designing a floating pontoon

[mink_mk]

I need help on an easier workflow that can help me achieve the desired buoyancy line of my pontoons.

We are designing many floating pontoons. Each pontoon has different dimensions and different weight distributions.

We know exactly the dimensions, weight, and center of mass of each pontoon, so we know the volume of the foam that we need to float the pontoon. These are known variables.

However in order to keep the buoyancy line level (not tilt to left, right, forward, or backward), we need to align center of mass of the pontoon to center of mass of the foam on XY plane.

Here is the example.  Grey color is the pontoon, and red is the foam.

Currently the way I do is I manually alter the shape of the foam bit by bit, so the the center of mass of the foam is aligned with center of mass of the pontoon. However it's very difficult and very time consuming, because each time I alter the shape of the foam, the volume of the foam also change, which effect the floating level

My questions are;

1. Is there anyway to design, alter or generate the shape of the foam, while I can fix (1) volume, (2) center of mass, and (3) one dimension parameter (i.e. fix width) of the foam?
2. If the first question is not possible, is there an easier workflow/way to design the foam to float my pontoon in the way that I want?

Thank you in advance for helps

[mink_mk]

Can anyone help please?

[jhackney1972]

The problem you face is the Center of Mass, in Fusion 360, is an internal function that you can only physically measure after it is calculated by the application.  There is no externally reported coordinates by the application to monitor in a dynamic fashion.  Since this is the case there is no practical way to calculate its position after a mass change except doing a manual measure meaning you cannot monitor the center of mass "dynamically" for calculations.

[mink_mk]

Thank you for your reply and explanation.  I guess I need to do the center of mass manually then.

I still have some more questions.  Is there anyway to fix the volume, while I try to alter the shape of foam?

For example, set a constrain to fix the width of the foam, then when I change the length (or angle), height will change automatically to maintain the same volume of the foam.  Is there a way to do this?

If this can be done, at least it takes one variable out of the manual job 😅

Thank you

[jhackney1972]

The Volume is a calculated value also by the application just like the Center of Mass.  Unless you know the programming language and the API of the application, I do not see any method of capturing the model volume much less freezing it.  You will have to accept, the process you are trying to do will probably be trail and error.

[mink_mk]

Thank you again for explanation.  I guess I need to continue trial and error job, or may be look for another software/solution to do this part of the job.