by Jim Aamodt
As mentioned in my previous Kermath article, Kermath Engines introduced the Sea Wolf Series in 1926. It surprisingly incorporated many of our contemporary design items. Lets consider how the Kermath Company formulated those designs.
Kermaths product line, unlike others, was almost exclusively 4 cycle engines with engine block and main castings built in-house. (Later in the 1930s, they adapted a marine adaptation for a Ford V8 and possibly other automotive based engines). Prior to 1926, all engines were of the flathead (L Head) configuration and of two, four, and six cylinder in-line design. Model names ranged from the older 2 cylinder, 4 cylinder heavy-duty, through the 4 cylinder Sea-Bird, Sea-Dog, Sea-Man and 6 cylinder Sea-Eagle, Sea-Master, Sea Queen, Sea-Mate, Sea Captain and the L Head 150 H.P. Sea King and Sea Farer.
The overhead valve (Sea Wolf type) was introduced in 1926, sharing the oil pan, oil reservoir, distributor, pistons, and crankshaft of their flathead 150 H.P. predecessor. The new engine was initially rated at 150 H.P. at 1800 RPM, displacing 648 cubic inches. A later 1928 version, the Sea Hawk, was rated at 175 H.P. Late in 1928, the 5 bore was retained, with the stroke increased to 5 3/4 to produce the 200 H.P. 678 cubic inch version. Within a few months, the slightly higher compression 225 H.P. version was marketed, which is the highest production model (through 1943) and known, as the Sea Wolf.
Until about 1936, all models of the new engine, contrary to contemporary practice, still retained low compression ratios, and non-counterbalanced crankshafts. However, there were for us motorheads (pardon me, Mr. Motorhead) some innovative features. Counter rotation models were very common for dual installations, and the Sea Wolf family engines could be assembled completely as a port to starboard mirror image. Intake and exhaust valves are the same size and interchangeably ported. Intake and exhaust manifolds can be exchanged to either side. Water pump drive (seawater) and distributor-oil pump drives could also be interchanged side to side. Thus, a twin engine installation could have port and starboard exhaust systems.
The earliest engines had two upper full length aluminum plates covering water jacket areas. Probably to reduce costs, each upper plate was replaced by two stamped metal plates for water jackets and three crankcase access covers on each side were also stamped steel. As these leaked like a sieve and rusted quickly, the plates were changed to cast iron in late 1928. To reduce the weight, the lower crankcase plates were also changed to aluminum in 1930.
The earliest 678 cubic inch engine, I have seen, had a single all brass Holley DDV-5 (WWI) downdraft carburetor. Other 1927-28 engines used dual 1 ½ Schlebler S Models, and later Holley dual downdraft units. The stabilization of design to twin updraft carburetors occurred in 1929. Initially they were 1 7/8 and later became 2 Strombergs. The addition of an oil cooler also appeared in 1929.
An engine of this size required a 12 volt starter, so all boats using it were usually wired 12 volt, even in the 1920s. The twin ignition system used two resistors to drop voltage to 6 volt as 12 volt coils were apparently not easily available.
Oil filters of the almost full flow type were standard on the line returning the oil from the crankcase to the front reservoir. However, the filter could be counted upon only to remove large rocks and birds. With an eight gallon crankcase capacity, considerable sediment simply settled to the bottom. In the late 1930s, a cartridge type low micron filter was used, but only on a partial flow system.
The early 1926-27 engines used a log intake manifold heated by crankcase oil on return to the reservoir. Later, updraft dual carb systems and the initial single DDV-5 intake manifold used exhaust heat internally ported, and then externally routed to the exhaust elbow.
Until the advent of the closed (freshwater) cooling systems, there were no belts or rubber hoses on the engine. All drives were geared, and all lines were copper. Kermath took pride and mentioned often in 1926-30 the clean, uncluttered aesthetic look of the Sea Wolf family. (This changed to a very complex look with added oil cooler closed cooling, etc. after 1930). The closed cooling engines used the generator gear drive for the seawater pump, and forced the generator forward with a flywheel belt drive. Closed cooling raised the engine weight from 1500 to 1650 pounds!
The Sea Raider Series was added in 1929. It was simply two six cylinder Sea Wolfs sharing a common crankcase, thus becoming a 1414 cubic inch V12! Originally rated at 300 H.P., most units sold in the 1930s were 450 H.P.
The early 1940s saw the stroke of the Sea Wolf six cylinder increased by ¼ to produce the 275 H.P. Sea Raider 6. The V12 was also stroked to 1560 cubic inches and became the Sea Raider 12 of 580 H.P. Counterbalanced crankshafts, internal rod oil passages, and several minor changes also occurred in the late 1930s.
Chris Craft, Sea Lyon, Garwood, Mathews, and many other builders utilized Kermath Sea Wolf engines. One of the largest supporters of Kermaths was John Hacker. Hacker Craft Boats used the 225 Sea Wolf in their 26 through 30 runabouts, and promoted the 450 Sea-Raider in their 33 models. John Hacker always preferred engines designed for marine use, and avoided earlier aircraft conversions, and in smaller boats, automotive conversions. He also designed two 450 H.P. Sea Raiders into his famous Tahoe boat, Thunderbird.
A current estimate of operating Sea Wolf engines is less than thirty. Of those, several are plumbed incorrectly as to exhaust manifold heat and high speed water pump overflow. However, the engines today still have a reputation as being sturdy and dependable. As the logo says, a Kermath always runs.
In the next issue, we will be less nuts and bolts, and have some fun looking at installed applications. We will also take a look at the companys last gasp for marketing, the Screwballs.
| BSLOL Main | BoatHouse Main | Chapter Information | Chandlery | Trading Dock | WayPoints |
A Chapter of the Antique & Classic Boat Society
©1999-2005 BSLOL ACBS Chapter