Mildew removal and control

The web site  yandina.com has some interesting information on their mildew removal and control. It reads...
Unfortunately mildew is a common problem on boats. Commercial mildew removers are expensive and have a limited life in storage. Apart from the obvious of keeping dry and ventilation, here are a couple of tips for combating mildew.

MILDEW REMOVAL

You will need to purchase some concentrate. I use AQUA CHEM spa care SHOCK TREATMENT. It is a white powder and the active ingredient is Lithium Hypochlorite, 29%. It is sold as a chlorinating shock treatment for spas and hot tubs and you will find it, or an equivalent, at any pool chemical supply. I purchased 16 ounces for $5.97 at Walmart. 16 ounces should supply enough mildew remover for approximately 50 years on a 71 foot boat!
Mix in the ratio of one level teaspoon of powder to one gallon of water. That teaspoon full doesn't look like it will be enough in that big gallon of water but don't be tempted to put more in - the powder is super concentrated and this ratio works very well. Since the label says it is a Federal offense to use this product other than indicated on the label, I suggest you take your boat out beyond the three mile limit before performing these illegal acts.
The solution should be kept in a sealed container, plastic bottles with a screw cap work well. Label well to avoid accidents. Transfer as required to a spray bottle but don't store it in the spray bottle since the air vent seems to allow the strength to weaken in a few days. Even in the sealed container it lasts only a few weeks but it is so cheap compared to commercial preparations - go ahead, make another gallon.
Don't dispose of excess solution or powder in the water unless extremely diluted as it is toxic to marine life. If left over solution gets too weak to use, I dilute it in my bilge and allow it to sit there exposed to the atmosphere for a few days before pumping overboard. So long as there is no oil in your bilge this helps keep your bilge clean and kills any smelly bacteria before emptying. I have a large bilge and plenty of ventilation, smaller boats might need to find an alternate disposal method but in small quantities it should not be worse than having an indoor spa.
On smooth surfaces - paint, vinyl, varnish etc., - spray on, leave a few seconds to work, and wipe off. You can even wet a paper towel and just wipe slowly and it will work. There is no need to rinse the surface, in fact I think the residue inhibits the re-growth of mildew. There is some chlorine smell so make sure you have plenty of ventilation.

REMOVING MILDEW FROM DOCK LINES, CANVAS, RIGGING AND ROUGH SURFACES

Chemicals and scrubbing work fine on smooth surfaces but on halyards, dock lines, awnings, etc it is impossible to scrub down into all the cavities so a black residue is left which not only still looks dirty but is the seed for new algae to start growing.
The easiest way to get these looking like new is a pressure washer. You can do lines without removing or lay them down and move them a couple of times until you get all sides. It doesn't take much pressure and you may do some damage with a commercial high pressure unit so experiment with a pressure adjustment if there is one, or back off sufficiently so there is just enough pressure to remove the dirt and mildew. Just use plain water, you don't need to add any soap, detergent chlorine or Lithium Hypochlorite.

MILDEW PREVENTION

Most marine stores and catalogs sell a product called DI-GAS or MIL-DU-GAS and I have occasionally seen the equivalent in WalMart. These products are labeled "HAZARDOUS TO HUMANS AND DOMESTIC ANIMALS" and contain PARAFORMALDEHYDE. When not sold to the marine market these products are labeled "NOT FOR INDOOR USE". With the restricted ventilation in boats this warning should be more applicable! CAUTION, they are quite nasty, in fact, if you use it as instructed you boat will become uninhabitable. DO NOT USE AS INSTRUCTED.
Despite the above warnings against these products, they do work well to prevent mildew and the "boat odors" in closets etc. Use these products by opening the seal as instructed but then enclosing them in a zip lock plastic bag. Cut a ¼" hole high in the side of the bag and hang in your closet. The reduced dissipation is still sufficient to prevent mildew and the bag of poison lasts a year or more instead of a couple of months. This works well for enclosed spaces but I do not recommend trying to control mildew by treating the whole boat space, unless the boat is unoccupied for an extended time.

Remote Battery Wiring

A separate battery to run a winch or bow thruster is cheaper, safer and works better than running a heavy cable from your starting or house bank.

This installation requires some electrical skills and since errors could cause an electrical fire you should not attempt it unless you feel confident. This project has not been checked for compliance with ABYC or USCG standards and the author presents this as a guideline to be interpreted by qualified installers. No warranty or guarantee is given or implied.

THE THEORY BEHIND THIS PROJECT

Winches and bow thrusters, located in the bow, are usually a long distance from the starting or house batteries. These items draw a heavy current for a short period of time. Unless you use very heavy cable for the long run, the voltage drop by the time it gets to the device, will have reduced the available power.
What is worse, however, is that very heavy copper cable is an invitation for an on-board fire if it gets shorted so for safety you have to add a large fuse - large enough to take the stalled motor load of the winch without giving you a nuisance blow - yet small enough that a short at the far end can draw enough current through that long cable to blow the fuse.

In many installations, these requirements conflict making practical current protection impossible.

The current drawn by the stalled motor is often so close to the current drawn by a short at the remote end that any fuse or circuit breaker that can protect against the short, will give nuisance blows just when you really need it.

PROVIDING A REMOTE BATTERY IS SAFER, CHEAPER AND WORKS BETTER

Instead of installing a very expensive heavy gauge copper line up AND BACK, and the expensive fuse to protect it, install a battery in the forepeak to provide local power. Now, the heavy wire is very short with very little voltage drop, and you can keep the battery charged with an economical charging line. Depending on the size of the device to be powered you can usually get by with a low cost automotive starting battery. These are made to take heavy loads for short periods of time and remain on float charge the rest of the running time. Since the charging line is low current, it is easy to provide fuse or circuit breaker protection. By installing a 50 amp combiner in series with the charging line, the remote battery will be maintained at full charge without any diode drop yet it will not discharge back into the house or starting battery.

NOTE:- Since there is a battery at each end of the charging line you need a fuse or circuit breaker at EACH end.

INSTALLATION

Parts List:-

• Automotive battery with enough capacity to run the device for the longest job. (Multiply AVERAGE current by time in hours to get amp-hours required, then double this figure. Example, 80 amps x 30/60 hours x 2 = 80AH ) For charging compatibility it should be the same type (lead-acid or gel) as the starting battery.
• 50 amp combiner The combiner should be mounted with the remote battery.
• Two fuses or circuit breakers. I prefer the automatic reset thermal breakers that are typical in the automotive industry. 
• A good quality battery box. 
• Red and Black cables for the charging line - 10 gauge is adequate.
• Conduit to protect charging line - essential on a metal boat, desirable on others.

Select a location for the forward battery. It should be ventillated because the battery will be on charge much of the time and producing small amounts of hydrogen that could be explosive if allowed to concentrate. Larger installations might consider an automatic power vent that only runs when dangerous gasses are being produced. A gel type battery is much less of an explosive gas problem but it is still present if overcharged.
Provide a SOLID mounting for the battery and battery box. Keep in mind that the bow takes much more of a pounding than the traditional battery locations so go overboard (not literally) on strengthening the mounting. The battery (box) must be rock solid when strapped down. Due to the motion and stresses, I would not use the conventional webbing strap they supply as the buckles provided are usually poor. Good quality ratcheting strap(s) of a material that is acid proof would be better, or provide a stainless retainer with through bolts and wing nuts.
Connect the device to the battery following manufacturer's suggestions. Connect the charging line, following this schematic and the installation instructions supplied with the combiner. If you use our thermal circuit breakers, you must use crimp on ring terminals to connect the wire - the screws are too small to adequately secure 10 gauge stranded wire, even if tinned.

24V from 12V

This is a traditional problem that typically has very dangerous and expensive switching. Typically it is done with a second battery that is kept in parallel with your 12 volt starting or house battery for charging, but is switched in series with that battery to run the 24 volt item - bow thruster, winch etc. This is expensive and dangerous. You have to use two very heavy duty switches, one to switch the negative of the additional battery from the -12 to the + 12 of the starting battery, and the other to disconnect the +12 of the additional battery from the starting battery.

BUT THE TIMING IS CRITICAL. If one switch is operated before the other you will end up shorting a battery and cause an explosion.

So here is how to do it the safe way using only a single pole single throw switch.

In the circuit diagram, you will see that the auxilliary battery is connected in parallel to the 12 volt battery through a pair of headlamps, one in the positive lead and one in the negative. With the "24 VOLT" switch open, the charge on the additional battery will be the same as the 12 volt starting battery because the headlamps, which carry a couple of amps when lit, will trickle charge the additional battery to the full voltage. Under normal circumstances, the headlamps will only have a fraction of a volt across them so except under heavy charging/discharging conditions they will stay off or have a very dim glow.
There will be 12 volts going to the 24 volt load when the switch is in the 12 volt position but since the headlamps are in series with the circuit, if the bow thruster were turned on, only a couple of amps would flow and the headlamps would light. When you close the 24 volt switch, the batteries are now in series and 24 volts is available for the bow thruster. While in the 24 volt mode, a couple of amps will flow through each headlamp and they will come on full brilliance. The amount of energy wasted, however, is small compared to the battery capacity and the few amps through them does not materially diminish the high current available for the thruster.

COMPONENT SELECTION

The BATTERY capacity of the auxiliary will be a function of how long you think you will need the bow thruster in one session, and how often sessions will occur. Refer to the bow thruster current requirements to determine this figure. For example, if the bow thruster draws 50 amps (about 1.5 horsepower) and you need to be able to run it for up to 30 minutes, that comes to 50 x 0.5hr = 25 amp hours. You should double this figure to provide a safety factor and reduce cycling the battery below the 50% charge level. So a 100 amp-hour automobile battery for about $35 would be ideal. You should match the chemistry of the battery to that of the starting battery - don't mix an AGM or GELL battery with a WET lead acid. Otherwise the batteries can be of different ages, manufacturers or style. You don't need a deep cycle battery here - the usage is more like that of a starter motor battery in an automobile.
Charging time after a typical use can be calculated by dividing the amp-hours used, say 25 in a 30 minute period, by the charging current, say 4 amps = 6 hours, or 12 times the discharge time.
The HEADLAMPS should usually be the highest wattage you can find. In fact I use a high/low beam headlamp and wire the high and low terminals together so both filaments are in parallel. The high temperature will reduce life but since they are only going to be on for a few minutes a day maximum, who cares? A major advantage of using headlamps to limit the current is that the resistance is non linear. As they cool down the resistance goes down dramatically and they tend to draw a constant current for charging even though they are not brightly lit. You should consider placing the headlamps so the light is visible from the bow thruster control panel location so you don't forget to switch back to CHARGING when the bow thruster is no longer needed, otherwise the headlamps will eventually discharge the auxiliary battery.
The SWITCH should be sized for the maximum current of the bow thruster plus a safety margin. For an economical installation, a simple battery disconnect switch is ideal. If you want a remote control, then you should use a simple single pole, normally open relay instead of the switch. We have a 130 amp relay in our Parts and Kits catalog that will handle many thrusters.
The CABLES should be sized as recommended by the bow thruster manufacturer with regard to the length of the run. Note that only the cables to the switch have to be this size. The cables to the headlamps only have to carry a few amps so a 12 or 14 gauge wire would be adequate.