I'm wondering if anyone has recommendations on good, affordable (less than $100) digital scales that would be good to use on a boat.  It would need to be shock-proof and be able to still be used in rough weather (i.e., large waves).  I'm looking for 2 scales both of which need to be accurate and with a precision of 0.1g; one for a max weight of around 3000g and one for a max weight of around 500g.

 Thanks!!