Freeland, the difference between the 18 gal tank full weight, and the tank you want to add is not appreciable on a displacement cruising sailboat
. If you are racing
her, different story. Since all this weight is centerline, that is best case. I see you are from Palm Beach. If you are considering cruising, a smallish water maker might be a better spend of time and money
. Regarding weight in the bow, do you have an all chain rode
or combination chain/rope? Either way, as I said above, the weight difference is not a major change in a cruising yacht.