I'm trying to model this freestanding soaker tub:

So far, this is where I am:

The bow and stern of the actual tub are curved, but my model just has straight lines between the top and bottom curve vertices.

How can I deform these surfaces to more closely resemble the actual tub? I contacted Modern Bathrooms (the distributor) and they sent me a PDF spec sheet but of course have no CAD files available. Here it is if it is more clear than the photo.

Thanks!