FAQ's

1. I have corrosion problems in the interior of my motor. Can Sunmatic correct this problem?
   
2. I have corrosion problems in the interior of my steel-hulled/aluminum-hulled boat. Can Sunmatic correct this problem?
   
3. I have stainless steel freshwater holding tanks in my boat that are isolated from the carbon steel hull but I have corrosion in the interior welds where there is water. Does the protection system for the exterior submerged parts prevent this?
   
4. Is it necessary to isolate the grounding points in an aluminum-hulled boat?
   
5. Is the same current needed when a boat is moored at a marina as when it is navigating?
   
6. How do you protect a propeller and its shaft in port or in a marina?
   
7. I have a steel hulled boat that has bubbles in the paint and water underneath the paint but there is no visible corrosion. Can this be due to Galvanic currents?
   
8. Can I protect a fiberglass or steel hulled boat with magnesium anodes in salt water?
   
9. Can I protect an aluminum-hulled boat with magnesium anodes in salt water?
   
10. What advantages does DC current (continuous) have in powering the titanium anodes over AC (alternating current)?
    
11. Is it possible that use of a protection system of impressed current will cause paint to peel off?
    
12. I have a steel hulled boat that has bubbles in the paint and water appears when I pinch them. In spite of the bubbles with water there is no visible indication of corrosion. Are these bubbles due to cathodic protection?
    
13. I have heard that aluminum boats are especially sensitive to the installation of cathodic protection systems. Can I use impressed current to protect this type of boat?

QUESTION 1:
I have corrosion problems in the interior of my motor. Can Sunmatic correct this problem?

ANSWER 1:
The protection system used for the submerged part of the boat does not resolve this problem, although it sometimes can help a little. This is because when all the metal on the boat is bridged or united in order to protect it, this prevents vagabond currents from circulating throughout the boat. If the corrosion is occurring inside pipes/tubes or interchangers of saltwater circuits/conduits, then a specific system of protection for pipes and tubes will be needed to protect them. In the case of corrosion of freshwater circulating systems, this can be resolved by replacing the system with a more resistant conduit (less conductive of current). This is possible because a freshwater system is closed.

QUESTION 2:
I have corrosion problems in the interior of my steel-hulled/aluminum-hulled boat. Can Sunmatic correct this problem?

ANSWER 2:
The interior galvanic circuit is independent of the exterior: a different electrolyte. For this reason the interior of the boat is not protected. Only if there was water in the interior and connected to another system could this area be protected. The best solution is to keep the area dry and well painted. In some boats where water in the bottom of the boat tends to accumulate, sacrificial anodes are sometimes used in those zones.

QUESTION 3:
I have stainless steel freshwater holding tanks in my boat that are isolated from the carbon steel hull but I have corrosion in the interior welds where there is water. Does the protection system for the exterior submerged parts prevent this?

ANSWER 3:
The protection system used for the submerged parts of the boat cannot prevent this. Connecting the tanks to the grounding point along with the rest of the metal parts can lessen the corrosion. It is a mistake to isolate the tanks from the rest of the metal. Additionally, titanium anodes would have to be inserted into the tubes and a protection system would have to be designed using impressed current. If you used sacrificial anodes to protect the tanks, they would dissolve and make the water non-potable due to the existence of heavy metals.

QUESTION 4:
Is it necessary to isolate the grounding points in an aluminum-hulled boat?

ANSWER 4:
No, to the contrary, isolating elements increases the likelihood for corrosion because we cannot control the potentials of the individual metals. To protect stainless steel or bronze you have to arrive at a reading of a minimum of -600mV. To protect steel you have to arrive at a reading of a minimum of -800mV. To protect aluminum you have to arrive at a reading of a minimum of -900mV (all measured using a silver reference electrode - silver chloride). If we unite all the metals and at the same time connect them to the negative of the battery we can situate the metals at the appropriate levels of protection of -900mV by sending positive current through the titanium anodes. This way all the metals will be protected; and this is controlled through a corrosion monitor incorporated in the system.

QUESTION 5:
Is the same current needed when a boat is moored at a marina as when it is navigating?

ANSWER 5:
No. They are completely different. Sometimes the current needed for navigation can be double the amount needed in port. It is very important to determine the protection needs for each situation. For this, a submersible reference electrode is needed as well as a voltage meter to measure those needs. Impressed current systems make it easy to adapt to any situation because the system can adjust the power being sent to the anodes. An initial study at the time of installation is the only requirement. The values determine the adjustments necessary when in port or under navigation. These values should suffice for the life of the system depending on the status of the bottom paint.

QUESTION 6:
How do you protect a propeller and its shaft in port or in a marina?

ANSWER 6:
An alternative would be to install sacrificial anodes on the shaft of the propeller in sufficient quantities or in the support nut of the propeller. This solution creates various inconveniences however and can cause turbulence due to the irregular dissolving of the anodes in the water. If the zinc ring-anodes don't have a steel sleeve inside them, then the width of the anode will continue to widen on the shaft producing damaging vibrations and noise until the anodes break loose and fall off.

To avoid these problems bronze rings should be installed on the shaft in the engine room with special contact brushes placed over the rings. The ring and brush transmit the negative current of the cathodic protection system resulting in the safety of the propeller and shaft.

QUESTION 7:
I have a steel-hulled boat that has bubbles in the paint and water underneath the paint but there is no visible corrosion. Can this be due to galvanic currents?

ANSWER 7:
It's very improbable. The most likely cause is probably due to bad paint application. To remove all doubt, you could do a study to determine the status of the protection when the boat is in the water. If the power readings show -1000mV or more, it is not due to the currents because paints should be able to resist up to -3000mV.without problems. Additionally, if the cause were due to current, the bubbles would appear all over the hull not just in zones, because electrical currents are wrapped all around the hull.

QUESTION 8:
Can I protect a fiberglass or steel-hulled boat with magnesium anodes in salt water?

ANSWER 8:
It's not advisable due to the great activity of the magnesium and the high negative potential of the anode. This causes the magnesium anode to dissolve extremely quickly and it would only survive a few days. Also, magnesium anodes are expensive and not very productive: barely reaching 56% effectiveness.

QUESTION 9:
Can I protect an aluminum-hulled boat with magnesium anodes in salt water?

ANSWER 9:
Not under any circumstance. Aluminum is protected within the following range of
-900mV to -1150mV. and a magnesium anode in an open circuit has a reading of
-1500mV. This can put the aluminum in a state of "overprotection" resulting in a chemical attack of the aluminum due to the PH balance of the cathode (the aluminium hull).

QUESTION 10:
What advantages does DC current (continuous) have in powering the titanium anodes over AC (alternating current)?

ANSWER 10:
Because the system uses DC current, the batteries can be used as a power source. The system uses sophisticated power regulators to control the battery usage and reduce the consumption necessary to protect the boat. The regulators send under 3 volts of current to the titanium anodes ensuring a minimal drain on the batteries. The system also makes it impossible to overprotect the boat. Even if someone were to turn the regulators to full power, it would never reach a reading of -1200mV: a reading still well below the point where paint begins to fall off.

QUESTION 11:
Is it possible that use of a protection system of impressed current will cause paint to peel off?

RESPUESTA 11:
It is impossible for this to occur with systems that use pre-programmed currents for port or navigation. This is because the system calculates values that are never to pass below -1100mV either in port or under navigation. Given that the limit for paints is above -3000mV, the possibility of paint peeling or falling off because of the system is null.

Additionally the Proytec system uses DC power and high tech equipment in order to ensure the least amount of battery drain. The system uses minimal power, under 3 volts, and even if someone were to turn the system to full power, it would barely reach -1200mV. This value is still way below the limit that would cause the paint to peel.

QUESTION 12:
I have a steel-hulled boat that has bubbles in the paint and water appears when I pinch them. In spite of the bubbles with water there is no visible indication of corrosion. Are these bubbles due to cathodic protection?

ANSWER 12:
No. Cathodic protection with sacrificial anodes makes it impossible for this scenario to occur with zinc or aluminum anodes (the only sacrificial anodes that can be used in saltwater) because the maximum protection that these anodes can provide is around
-1150mV. In the case of zinc anodes the maximum achievable protection is
-1050mV. These described scenarios picture an absolutely perfect situation where anodes are spread all over the hull (an expensive, difficult and turbulence causing scenario) .

Commercial bottom paints should resist up to -3000mV and in some cases up to
-4000mV. For this reason the cause for the bubbles should be searched in the paint itself or in contamination during paint application.

To reach those levels of dangerous current is very difficult (not impossible but very unlikely) with impressed current systems and a series of events would have to take place for it to happen:

• Failure of automated control system (in automatic regulated systems)
• Short circuit of positive reference electrodes for metal (only for silver - Silver-
  Chloride reference electrodes; (zinc reference electrodes don't have this risk)
• Extremely high current needs to be sent to the anodes (sufficiently higher than the limit indicated to cause paint to peel)
• Using protection that is oversized (or too powerful) for the size of the boat to be protected.

Additionally, all of these conditions would have to be in effect for a long period of time to cause the paint to peel.

QUESTION 13:
I have heard that aluminum boats are especially sensitive to the installation of cathodic protection systems. Can I use impressed current to protect this type of boat?

ANSWER 13:
You can absolutely use these protection systems for aluminum boats as long as the following precautions are taken.

Aluminum, like all metals, has its own characteristic minimum protection value, in this case the value is -900mV (-650mV for bronze/stainless steel, -800mV for steel, as measured by a Silver - Silver-Chloride electrode). The greatest problem with protecting aluminum is overprotection by exceeding the determined safe value (between -1200mV and 1300mV). The PH basis that would develop due to overprotection would attack the aluminum chemically and would corrode the metal even faster than through normal corrosion.

To protect against this type of overprotection in this type of boat, the following is recommended:

• Abstain from using totally automatic protection systems because they depend on a series of factors, none of which are reliable. In the first place, these automatic systems are very sensitive to the frequent power spikes found on boats (especially on fishing boats) resulting in repeated replacements of these systems. Secondly, any oscillations in the electrode readings (such as those caused by electronic noise typical on boats), causes the equipment to apply or decrease power unnecessarily, given that the status for protection has not actually changed.

  Numerous studies have shown that boats really only have two protection values of concern: one in port and one while under navigation. These are the only two situations where the danger of corrosion can vary for a boat. It is much safer and reliable to use a system that is pre-programmed or adjusted manually (with two settings: docked or navigating) because they can be regulated never to reach those dangerous levels under any circumstances.

  These automated systems also work with high power; precisely the risky situation that we are trying to avoid in the first place (overprotection). For this reason Proytec equipment uses oversized anodes that function at extremely low power settings (under 2 volts), which not only save electricity, but also eliminate the risk of overprotection of the hull (regardless of the regulator settings).

• Situate the regulator in a clearly visible location so that the current in port or under navigation can be verified at any moment (ex. by using the amp meter incorporated in Proytec's regulator).
  

• Situate a power meter (measures readings) in a clearly visible location on the bridge so that various readings can be compared (the current being administered to the boat by the regulator to protect it versus the status of the boat registered by the meter).

The Proytec system was designed so that it would not pose any type of threat or danger to an aluminum boat. For this reason, the system was designed from the ground up and parted company with existing systems designed for large ships. The main reason for this departure in design and theory is because smaller boats or vessels cannot dedicate the same resources of energy or human capital to maintain and oversee these costly automatic systems in a responsible manner.