Abstract: The invention relates to a method and apparatus for enhancing the heat transfer efficiency of a keel cooler by increasing the flow rate of coolant through the side tubes. Because the side tubes are exposed to a greater amount of fresh unhindered seawater, increasing the flow rate through the side tubes can have the effect of enhancing the overall heat transfer capability of the keel cooler. The invention relates to using apertures leading to the side tubes from the header and vice versa that are substantially arrow-shaped in design, wherein various benefits that lead to an increased flow rate are provided. The aperture is preferably symmetrically shaped so that a single die can be used to cut the aperture onto both side walls of the header.

Abstract: The invention relates to a method and apparatus for enhancing the heat transfer efficiency of a keel cooler by increasing the flow rate of coolant through the side tubes. Because the side tubes are exposed to a greater amount of fresh unhindered seawater, increasing the flow rate through the side tubes can have the effect of enhancing the overall heat transfer capability of the keel cooler. The invention relates to using apertures leading to the side tubes from the header and vice versa that are substantially arrow-shaped in design, wherein various benefits that lead to an increased flow rate are provided. The aperture is preferably symmetrically shaped so that a single die can be used to cut the aperture onto both side walls of the header.

Abstract: An outboard marine heat exchanger comprises a plurality of cooling tubes positioned between opposing headers. Each header is equipped with a header flange having a plurality of fastening components. The fastening components are designed to mate with corresponding fastening components of a mating flange. In one embodiment, the mating flange interfaces with a pipe stub extending outwardly from a marine vessel hull. The header flange can then be attached to the mating flange to connect the heat exchanger to the cooling system of the vessel engine without the need to access the interior of the hull.