User manual STANDARD HORIZON P79

[. . . ] The lower the noise level, the higher the echosounder gain setting that can be used. Placement Choose a location where: · The water flowing across the hull is smoothest with a minimum of bubbles and turbulence (especially at high speeds). · The hull below the transducer will be in contact with the water. · The transducer beam will be unobstructed by the keel or propeller shaft(s). · There is adequate headroom inside the vessel for the height of the housing, tightening the locking ring, and removing the transducer. Caution: Do not mount the sensor: Near water intake or discharge openings Behind strakes, fittings, or hull irregularities Behind eroding paint (an indication of turbulence) AIRMAR pressure waves ® · Fin keel sailboat--Mount to the side of the centerline and forward of the fin keel 300­600mm (1­2'). [. . . ] Press the active face against the hull with a twisting motion (see Figure 3-C). After testing, wipe all traces of the lubricant from the transducer's face. Boat Types (see Figure 1) · Displacement hull powerboat--Locate 1/3 aft LWL and 150­300mm (6­12") off the centerline on the side of the hull where the propeller is moving downward. · Planing hull powerboat--Mount well aft, on or near the centerline, and well inboard of the first set of lifting strakes to insure that the transducer is in contact with the water at high speeds. Step-hull--Mount just ahead of the first step. AIRMAR ® AIRMAR ® A B C active face Figure 2. Testing the transducer at the selected location AIRMAR base ® AIRMAR keel keel direction arrow ® hull flange guideline perpendicular to keel parallel to waterline deadrise angle keel direction arrow Figure 4. Aligning the flange of the base (4°­12° deadrise angle shown) Observe the echosounder's performance, and compare it to the baseline. If you are testing a fishfinder, compare the thickness and intensity of the bottom trace. If the performance is close to the baseline, this is a good mounting location. If the test reading differs markedly from the baseline, you will need to find another location to install the sensor. If there is no reading or it is erratic, the transducer may be positioned over coring which is absorbing the acoustic energy. If no other spot is available, check with the boat manufacturer to be certain coring is present before proceeding with the instructions for "Installation in a Cored Fiberglass Hull" on page 4. Caution: The base must be liquid-tight. DO NOT use an epoxy adhesive, polyurethane based sealant, or the previously recommended Boatlife® Life Seal® or 3MTM 4200. 6. When you are satisfied that the location of the transducer is optimal and the orientation of the base corresponds to the deadrise angle of your boat, apply a bead of silicone sealant (such as GE Silicone I or Silicone II) to the underside of the flange of the base. (Follow the sealant manufacturer's instructions for its use. ) Press the flange firmly in place to form a liquid-tight seal. Turn the housing until the rib that most closely corresponds to the deadrise angle of your hull is aligned with the angle indicator on the locking ring. To secure the housing to the locking ring, insert the two screws (see Figure 6). Measure the deadrise angle of the hull at the selected location using a digital level, or bubble level and protractor (see Figure 4). Measure carefully, since the installed transducer must be within 5° of vertical. AIRMAR ® transducer Warning: Always wear safety goggles and a dust mask. 2. The hull surface to be bonded must be smooth and free of paint or any other finish. If the surface is rough, use a disk sander to smooth an area 100mm (4") in diameter. [. . . ] Apply only light pressure to the hole saw after cutting through the inner skin to avoid accidentally cutting the outer hull. Remove the plug of core material, so the inner core of the hull is fully exposed. Sand the inside surface of the outer skin using a miniature disk sander. Clean and dry both the inside surface of the outer skin and the housing with a weak solvent, such as alcohol, to remove any dust, grease, or oil. [. . . ]