How can shippers find capacity?

do you mean capacity to carry or capacity to handle business,anyway i believe proper planning is important,finding new open markets with moderate competition,open unrestricted communication with all parties concerned is as important,strong regular business partners with known orders sizes  and supply and demand forcasted figures .

i believe regular markets have expected performance and business size can be forcasted,but the big challenge comes when you are dealing with volatile markets like iraq,libya...etc.where forcasting would not be accurate,we have resorted to renting extra vessles and taking a chance of loading to at least90% capacity ,only to find out in our third run that demand dropped to almost20% sustaining a good loss.

local and international experience is key

I agree with Mr. Ameer Jayyousi