SEAKEEPER TECHNICAL FAQ'S

Below are some technical questions our Technical/Engineering Department is asked about the system:

Q. Why is a separate through hull necessary and how does the fail safe solenoid and moisture detector function?
Q. Why doesn’t the seawater pump stop when I toggle the switch in the computer pump control program window?

• First: To make accurate measurements, the seawater being analyzed must neither be contaminated with any of the organisms which can build up and reside in sea chests nor can it be exposed to any metals, paints or anti fouling materials.
• Second: In order to make an accurate determination of Sea Surface Temperature the seawater must be monitored outside the ship away from any heat being stored or generated through the hull.
• Third: To prevent the lift pump that circulates water through the monitoring system from stripping dissolved gasses out of solution we need to present the water to this pump under a slight positive pressure.

We have devised a through hull penetration system that comprises several components in order to achieve these objectives and to eliminate any risk of catastrophic leakage from this system.

A 1.5 inch internal diameter through hull penetration and gate valve has been designed. Externally a faired pod, protruding approximately 4 inches from the hull, with a self cleaning screen, constructed from Teflon acts as a scoop generating a dynamic pressure as the vessel moves through the water and providing a platform separated from the hull for mounting the sea surface temperature thermometer. This scoop, or pod, is attached by glass filled Delryn threaded rods that will shear off if the pod is impacted by flotsam rather than translate enough force to damage the hull.

A probe head constructed from Teflon and attached to a thin wall Teflon tube is inserted from inside the hull, while the vessel is in the water. This probe passes through the open gate valve and seats into the external pod where it forms an 'O' ring seal so that the water being drawn through the system is exposed only to Teflon, which is chemically inert.

The probe head contains a Platinum resistance thermometer and a pair of Platinum electrodes, which under the control of the SeaKeepers computer system can generate controlled volumes of Chlorine to sterilize the system and provide a signal that may be utilized to calibrate some optical sensors.

The gate valve has been sharpened so that it will easily cut through the Teflon hose and wiring to positively isolate the through hull penetration. On the inside of the gate valve a solenoid valve is coupled to a leak detector in the sampling module enclosure so that if moisture or leakage is detected in the enclosure the water intake will be isolated.

Q.Why doesn’t the seawater pump stop when I toggle the switch in the computer pump control program window?
A. This is only a problem with the versions of the SeaKeepers system that power the pump through a National Instruments relay board. The program that controls the pump is called PumpOn or PumpOn8. The default mode of the program is pump on continuously, which means the pump will start when the computer is powered and continue to run until it is stopped by the pump control program or the computer is powered off. The program executes once when it is started, but it does not continuous update.

To toggle the software switch, in the Pump display window move the switch to the up or down position with the mouse. Click on the single arrow on the upper left part of the window, or from the Operate menu, select Run. Either action will run the program once and implement the change requested. Toggling the virtual switch by itself will not make anything happen.

There is also a hardware switch on the relay board. It is a slide switch on the upper edge, behind the first indicator light. When the board is powered and turned on, the light is red. Behind the switch are green lights, which turn on when the relays are activated.