- #1

- 4

- 0

## Main Question or Discussion Point

Hi, I'm new here, great forum!

I am building a boat rack for the top of my truck for a particular boat and boat dolly. The boat will be upside down with the beach dolly attached. It is a side loader, so balance is critical. I need to calculate the combined Center Of Gravity (COG) of the boat and dolly before I will have them together to be able to measure it with a hoist. I have come up with a common sense equation for this, but sometimes in physics things that you think are simple and linear are not. Thanks for any information. I don't know if it is the correct term, but I am using COG as the balance point of an object when the fulcrum is placed below the object.

First, I have a rudimentary question about COG that may seem ridiculous, but this is not my field and I do not assume I know anything until I know it.

If I want 75% of the boat weight to be on the rear axle, do I place the Boat COG 25% of the wheelbase(C) ahead of the rear axle?

Now for the composite part. Two objects A and B are stacked and I need to calculate the combined COG of the stack. Obviously, the combined COG will fall somewhere between the two object COGs. Can I calculate the distance (x) that the combined COG moves away from the Object A COG as (Y)*(MassB/MassA) ? In this example it would be Y/4.

I am building a boat rack for the top of my truck for a particular boat and boat dolly. The boat will be upside down with the beach dolly attached. It is a side loader, so balance is critical. I need to calculate the combined Center Of Gravity (COG) of the boat and dolly before I will have them together to be able to measure it with a hoist. I have come up with a common sense equation for this, but sometimes in physics things that you think are simple and linear are not. Thanks for any information. I don't know if it is the correct term, but I am using COG as the balance point of an object when the fulcrum is placed below the object.

First, I have a rudimentary question about COG that may seem ridiculous, but this is not my field and I do not assume I know anything until I know it.

If I want 75% of the boat weight to be on the rear axle, do I place the Boat COG 25% of the wheelbase(C) ahead of the rear axle?

Now for the composite part. Two objects A and B are stacked and I need to calculate the combined COG of the stack. Obviously, the combined COG will fall somewhere between the two object COGs. Can I calculate the distance (x) that the combined COG moves away from the Object A COG as (Y)*(MassB/MassA) ? In this example it would be Y/4.

Last edited: