Calculating Vessel Utilization in Budget Projections

I am trying to calculate Vessel Utilization which in itself is not posing any problems but what is causing me problems is the fact that I am trying to do multiple calculations. I am trying to determine the number of days worked, Idle days, Repair Days in the same spreadsheet. I am trying to calculate the # of worked days based upon me changing the % of utilization but also to take into account a manual entry for Repair days and Shipyard Days.

The attached spreadsheet shows what I am trying to accomplish and only the areas in yellow are editable cells, the rest should be calculated with a formula.

Can someone point me in the right direction.

Thanks
Ray