As owners and crew, we all spend a lot of time and effort maintaining the finish on our boats. If we don't, the finish will soon disappear, taking a chunk of your boat's value with it. Along with waxing, regular washing and drying are the two primary factors in keeping the boat's finish in top shape. However, if you're too heavy-handed or use the wrong products, you can wash and chamois away your finish in very short order. And if you don't pay attention to the amount of water left on your boat every morning when the dew settles, it will burn into your finish when the sun comes up. Many top crews start their day with a hose-off and a chamois to remove the dew and dirt that has settled on the boat overnight, leaving a clean surface to fish on.
Even the water you use to wash down the boat can contribute to the degradation of your finish if you don't take the proper steps. Where I grew up on the East Coast, we had very good water with little or no mineral content. The sand aquifers that the water traveled through filtered the hard minerals out and made our washdowns relatively easy. However, in many places throughout the world, the water does not have a chance to filter through fine sand and is delivered to your hose with elevated amounts of calcium, magnesium, iron and lime - the things that make water "hard" and leave spots on your finish and scale in all your onboard plumbing and water-fed equipment.
South Florida is notorious for its hard water, and through the years several companies have developed products to "soften" the water delivered to your boat at dockside. These portable units, once considered a high-dollar luxury item, are commonly used today and can be seen behind many boats, connected in-line to the washdown hose. These rechargeable units treat large quantities of water and work much like water softeners engineered for the home. Filled with resin pellets and recharged with rock-salt crystals, the units remove or reduce the inherent calcium and magnesium carried in the water. They can also eliminate iron and other minerals specific to your location.
Being a bit of an old-schooler, I don't carry one of these deals aboard the rig I work on for several reasons. It always seemed funny to me that we spend so much time working to remove the salt water from the boat after a day's fishing or just from the salt-air environment in which the sport-fishers sit to then wash the boat with water softened by salt. Certainly, there is not as much salt in these units as in concentrations of seawater, but there is salt. This doesn't mean you shouldn't use one; in fact, they just might be exactly what you need to help your maintenance program.
Having said all this, I don't carry a water softener because we use the onboard water that we make with our watermaker to wash down our boat. We run our watermaker regularly as we fish and travel, and we have the capacity to carry what we need for a full washdown. There's also enough to keep the ice makers running and for showers at the end of the day. The water we produce does not spot and leaves no scale in the boat's plumbing or equipment. If by chance we need to use the dock water, we add a bit of vinegar to our buckets or wipe the boat with a chamois dipped in a water-and-vinegar solution to alleviate or remove whatever spotting we see.
Back in the day, while fishing in Mexico (a place notorious for bad water), we would wash the boat every day with vinegar as a regular part of our soaping. This kept the spotting down, and we didn't have to come back home and work for a week to remove the scale that would accumulate on the boat over a couple of months. We used soap only once a week to keep the detergents from removing our wax and harming our finish. However, the cockpit got soaped every day, and if we really took a lot of spray, we soaped the entire boat; other than that, we just rinsed it down with water.
So if you don't use a regular crew or constantly visit places with marginal water, you should consider purchasing a water-softening unit. One of the most popular models around is the Wet Spot, a PVC-cased unit that stows easily for travel and has a great reputation among the pros who use it. Offering various sizes for different quantities of water production, Wet Spot makes a unit to match just about any size boat. The Plus model for boats up to 85 feet treats 2,500 gallons; the Heavy Duty for boats 70 to 105 feet treats 3,500 gallons; and the Super is recommended for boats exceeding 100 feet and treats 5,500 gallons of water. A new unit, the Squirt, is made for boats less than 40 feet. These are basic guidelines based on Wet Spot's experience; however, your conditions might warrant more or less of a unit for your size boat depending on where you are using it.
Another new product by a company called Aquaonics claims completely spot-free water without using salt to charge the unit. Using resin pellets in disposable bags, the Aquaonics unit can deliver approximately 2,500 gallons of treated water. Using the supplied water-quality meter, you can measure the effectiveness of the unit or health of the pellets regularly by measuring the parts per million of minerals in the water. Once the unit tests higher than 30 ppm, remove the resin pellet bag and replace it with a new one. The interesting thing about this type of system is that there is no recharging canister to carry and no salt needed to recharge. You will have to determine whether that is a good or bad thing. In the meantime, we'll be watching to see what technology comes next to replace our chamois - now that would be something we all would use.