loan balance 172,432 (2 homes collateral) one home is in flood zone and has flood policy for 60,000. RCF is 100,000 appraisal is 69,500 ( the hazard policy has 69,000). I can't figure out if underinsured for flood. I tried using one of those calculation worksheets but am still puzzled.

What is the insurable value of the house in the flood zone? If it is not a principal dwelling, then you need the actual cost value of the structure.

first off I had the loan balance wrong -- it is 119,964 it is a principal dwelling on the insurance value the hazard is 69,000 but the flood policy has 60,000 I thought I could use the appraised value less land value plus foundation cost which then leaves me 3,897 short on flood coverage

Sounds like you are short whether you use the appraisal or compare the other hazard insurance.

Because you have a RCV, I would not use the insurance...there is too much question with that and is typically a last resort...and as you indicate, susane, it's missing the foundation at a bare minimum.

It would appear your minimum will be $100,000 on the flood.

It depends on whether you are a bank or mortgage company, what does your company use to determine insurable value? Is only one of the home located in a flood zone?