In this type of depressed market, a water view will make a slight difference in the market value, depending on the type of water view. Do you have to lean out of the bathroom window to see the water? Is it a water view in the winter only, when the leaves are off of the trees? Is it a view you can enjoy while having coffee in the kitchen, AND the diningroom, AND the livingroom, etc?
In a GOOD market, a complete ocean view without much chance of being lost by future construction, etc., will add a 20% to 30% increase in market value.
In a BAD market, it may only make the property MUCH more competitive.
It's hard for an appraiser to use comps from Swampscott and Marblehead for a Lynn property. In a GOOD market with little inventory available, they might be able to persuade a lender to use a comp close by in Swampscott or Nahant. It's not going to happen in this market. Even if nothing has closed in the past six months with a good view, the appraiser will use Diamond District comps and add onto the value to compensate for the view.
When I bought my house on the water on Sluice Pond, none of the comps were ON the water. The appraisers know how to adjust for the view.