Section 3 Cooling System

3.1 Ventilation

Engine combustion, generator cooling, and expulsion of flammable and lethal fumes require ventilation. Provide ventilation compliant with USCG Regulations governing sizing of vents and other considerations.

As a rule, size each inlet- and outlet-vent area to a minimum of 13 sq. cm/30.5 cm (2 sq. in. per ft.) of the craft’s beam. Should this rule conflict with USCG Regulations, follow USCG Regulations. For applications with screened inlets, double the size (4 sq. in. per ft.) of the hull/deck openings. Extend the vent ducts to bilges to expel heavier-than-air fumes.

For generator sets mounted in the engine compartment, increase the air flow to allow for the generator set’s requirements. Install optional detection devices to cause alarm, warning, or engine shutdown should dangerous fumes accumulate in the compartment.

See the generator set specification sheet that shipped with the generator set for air requirements. The air intake silencer/cleaner provides combustion air to the engine. Do not compromise the recommended minimum clearance of 38 mm (1.5 in.) between a duct opening and enclosure wall. The engine/generator performance will decline if you compromise these guidelines. See Figure 3-1 for allowable intake restriction.

Note: ISO 3046 derates apply. See Appendix C.

Model

Allowable Intake Restriction

 

 

3.5EFOZ/4EOZ

200 mm H2O (1.96 kPa or less)

 

 

4--125EFOZ/5--150EOZ

635 mm H2O (6.23 kPa or less)

Figure 3-1 Combustion Air Intake Restriction

3.2 Cooling System Components

The marine generator set’s cooling system requires the following components.

3.2.1Intake Through-Hull Strainer (Seacock Cover)

Install a screened-intake, through-hull strainer to prevent entry of foreign objects. Use perforated, slotted-hole, or unrestricted-hole design strainers. See Figure 3-2 for examples of typical strainers. The inner diameter of the strainer opening must be equal to or greater than the inner diameter of the water-line hose to the seawater pump.

1

2

3

4

5

1-789

1.Inside packing

2.Outside packing

3.Seacock cover

4.Direction of vessel movement

5.Typical intake through-hull strainers

Figure 3-2 Seacock Installation

Do not align the strainer (in relation to the craft’s direction of travel) with any other through-hull intakes. See Figure 3-3. Flush mount the recommended through-hull strainer. Install slotted-hole-design strainers with the slots parallel to the direction of the vessel’s movement.

2

1

4 3

Note: Position the intakes in relation to the vessel’s

travel so neither is in the wake of the other.

1-789

 

1.Generator set intake

2.Main engine intake

3.Aft (rearward)

4.Fore (forward)

Figure 3-3 Intake Strainer

TP-6069 6/03

Section 3 Cooling System

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Kohler 13EFOZ/15.5EOZ, 8.5EFOZ manual Ventilation, Cooling System Components, Intake Through-Hull Strainer Seacock Cover