Is there a way to do this?

On my boat I have ballast tanks that carry different cargoes.

example: cell A1 to A5 will contain the name of the product. and cell B1 to
B5 will contain amount of barrels in the tank.
lets say the products are ballast water, fresh water, or potable water. in
Cells C1 to C5 I want a formula to track how many bbls of what product is in
the tanks. example: if I enter "fresh water" in A1 and A2 and B1 and B2
contain 100. then a cell in the C row will say "200 bbls fresh water".

I know how to do this using the sumif function but, I want to be able to
change the product names in A1 to A5 to any text and still have the cells in
C row keep track of what that text is and how many bbls are in the cell in
the B row corrosponding to that tank.

And stated different, with sumif I can do =sumif(A1:A5,"fresh water",B1:B5)
for every cell that says "fresh water then the no. value stored in the cell
next to it in the B row will be totaled in the c row and say "200 bbls fresh
water". but I want to be able to change the product name in row A to whatever
I want and still have the C row track it the same way.

I tried to make this clear but I dont know if I did.

I have win xp home and XP office excel 2002.

Any insight would help.

thanks in advance

Greg