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The early 1920’s and 1930’s boats were characterized by so-called displacement hulls and fairly heavy and inefficient gasoline powered engines.  If you see a wooden boat with a narrow beam and a sharp, almost vertical bow, it is very likely a displacement hull from the 1920’s.  Without getting too far down in the weeds for readers with limited interest in historical boating, there was a significant improvement in technology when boat designers changed from displacement hulls to planing hulls.

 

The Invention of Hydroplaning Hulls Changes Boat Racing

A displacement hull rides down in the water along the full surface of the bottom of a boat.  Thus, because a boat floats because the water exerts force on the bottom of a boat and the bottom of the boat pushes back, a displacement hull moving through the water is pushing all the water being displaced, which causes a significant drag on the forward progress of the boat.  Since water is heavy, it takes a lot of horsepower to overcome this drag and early inefficient engine design just wasn’t able to produce much speed.  Henry Kaiser’s first boat on Lake Placid as a young man was a displacement hull skiff with an inefficient naphtha-powered engine and was only capable of 7 to 8 miles per hour.    

 

By the later 1930’s, hull design had moved to so-called planing hulls where the boat actually got up out of the water a bit to ride on the surface with a smaller amount of the hull actually being in the water at all.  The reduced drag from a planing hull allowed the boat to go much faster with the same amount of horsepower.  Fortunately, engine design was improving as well, so average speeds for pleasure boats were increasing significantly. 

 

Some of the larger boats were starting to use World War I surplus aircraft engines with much more favorable horsepower to weight ratios than standard boat engines.  These large-engine, planing hull powerboats were the favorites of the Tahoe West Shore racing crowd.  Henry Kaiser’s first boat on Lake Tahoe, Bess, was a Baby Gar (Gar Wood) planing hull powered by a Scripps boat engine.  Henry realized that this boat was great for family touring and speed boat rides, but just wouldn’t do for racing.  After having some early success with Bess before she burned in 1937, Henry acquired what was to be his long term go-to speed boat, Hornet II.

 

Hornet II featured the next breakthrough in hull design, the stepped hydroplane hull.  A rare boat built by Gar Wood specifically for racing use, Hornet II had a lateral notch in the hull structure about two thirds of the length of the boat from the bow.  The design idea was that the boat would ride on the water surface at only two points, an area slightly ahead of the lateral notch, and a small area at the very stern of the boat aft of the propeller and rudder.  This meant a small wetted surface and a relatively small amount of drag.  Hulls of this design were known as two-point hydroplanes and they dominated racing for many years.  Hornet II also featured a World War I aircraft engine known as a Liberty engine with a favorable horsepower to weight ratio for its time.

 

Technology marches on, and it wasn’t long before the two-point hydroplane was yesterday’s news.  In 1930, Arno Apel, at the venerable Ventnor Boat Corporation in New Jersey, patented the next big breakthrough in hull design, the so-called three-point hydroplane.  While Apel’s hull design was really just an advancement of the earlier two-point hydroplane design, the real breakthrough was designing a hull architecture that could take full advantage of the dramatic advances that were taking place in engine horsepower to weight ratios.  Like the two-point hydro design, the primary objective was to cut the wetted surface of the hull to the very minimum needed to keep the boat on the surface of the water, and not in the air like an airplane.  The genius of the design was to add two “sponsons”, small hulls at the port and starboard sides of the bow of the boat, with a small wetted surface about the size of a handkerchief on each sponson as two points of contact, and then use a surface-piercing propeller as the third point of contact with the water. 

 

 

 

 

 

 

 

 

 

 

 

 

 

This prop-riding feature of three-point hydroplanes is what most sets them apart from prior race boat designs.  Typically spinning a two or three blade propeller at 8,000 revolutions per minute (rpms) or more, three-point hydroplanes create a spectacular “rooster tail” spray of water behind the boat that excites and is much beloved by race boat fans. 

 

War Surplus Aircraft Engines Power the New Hull Designs  

The combination of two and three-point hull design and brute horsepower from WW I and WW II surplus aircraft engines set the stage for what we have called the Thunderboat Era of boat racing on Lake Tahoe.

 

Liberty Aircraft Engines:  The first war surplus aircraft engine to cross-over to valuable post-war commercial use was the Liberty L-12, a 12-cylinder, 45-degree banked, naturally-aspirated, liquid cooled engine displacing 1,649 cubic inches and rated at 400 horsepower.  The Liberty engine boasted one of the highest horsepower to weight ratios of its time, critical in both aircraft and racing boat applications.

 

Remarkably, this engine was designed over a 5-day period beginning May 29, 1917 by a team of engineers from Packard Motors and Hall-Scott at the Willard Hotel in Washington, D. C.  The United States had declared war on Germany a month earlier and was desperate for an aircraft engine that would surpass those currently being produced in England and Germany.  The U.S. Government called on the Cadillac Division of General Motors to quickly ramp up production of the newly designed Liberty engines.   

 

As an interesting historical side note, William C. Durant, then Chief Executive Officer of General Motors and an ardent pacifist, refused the Government’s request, and went even further by refusing to allow Cadillac facilities to be used for the production of any wartime materials.  This despite the fact that the United States was in an officially declared state of war with Germany and its allies. 

 

Stepping into this breach, Cadillac executive Henry Leland left Cadillac to form a new competitor to Cadillac, the Lincoln Motor Company to produce the new Liberty engines for the War.  Leland quickly got a $10 million ($218 million) order from the US Government to produce 6,000 engines.  The order was later increased to a total of 17,000 engines for $28.3 million ($620 million), pending an option choice by the Government based on the length of the War. 

 

Fortunately, it was not necessary for the Government to utilize its full options for engines.  In addition to Lincoln Motor, Liberty engines were built by Buick, Ford, Marmon and Packard.  In all, 20,478 Liberty engines were produced.  The engines cost the US Government approximately $1,670 ($36,504) each, and were later available on the war surplus market for $100 ($2,188) each.  Henry Kaiser’s first race boat, Hornet II, was originally fitted with a war surplus Liberty L-12 engine.

 

As a final chapter to the historical footnote regarding pacifist William Durant at General Motors, apparently he saw the light when news of the eye-popping engine orders for new competitor Lincoln Motors was announced.  His pacifist views quickly went out the window and he allowed both Buick and Cadillac Divisions to produce Liberty engines.

 

Allison Aircraft Engines:  The Allison V-1710 is a 12-cylinder, 60-degree banked, liquid cooled, single stage supercharged (and later turbo-supercharged) engine displacing 1,710 cubic inches, rated at 1,450+ horsepower depending on the configuration.  The genius of the Allison design was that it was modular, allowing parts of the engine to be produced by other manufacturers if necessary, and to enable designers to use the modules most appropriate for the particular application.  The Allison engine was designed by the Allison Division of General Motors for World War II use in a wide variety of applications including aircraft, ships, and heavy military vehicles (apparently Durant was gone from General Motors by that point). 

 

Liquid cooled Allison’s powered such famous WW II aircraft as the P-38 Lightning, the P-39 Aircobra, the P-40 Warhawk, and the P-82 Twin Mustang.  Like the Liberty L-12 before it, Allison engines offered an unbeatable combination of relatively light weight and very high horsepower.  Allison engines weighed about the same as predecessor Liberty engines but had almost 4 times the horsepower rating, a very important step forward in technology.  These engines cost the U.S. Government well over $25,000 ($499,284) each, but were available after the War for about $400 ($4,700) or less for a brand new, never uncrated engine.  Kaiser’s assistant Handy Hancock wrote that Kaiser acquired “dozens” of these engines at an average cost of about $100 ($1,175) on the war surplus market. 

 

Allison engines are credited with “saving” hydroplane racing by making the sport (barely) affordable.  For example, a racer could purchase an uncrated Allison V-1710 for $400 ($4,700), a racing gear box for about $1,500 ($17,626), a water-cooled manifold for around $450 ($5,236), a hydroplane hull for $8,000 ($94,002) and be ready for big-time hydroplane racing.    

 

Kaiser used Allison engines to power all his race boats, beginning by refitting Hornet II’s Liberty L-12 engine, first with a Packard 1A-1237 engine, and then a V-1710 Allison engine.  Henry preferred Allison’s because they were made in the United States.  He was personally very close to engineers at the Company and called upon them frequently for design advice, particularly during his national racing campaigns.  By the way, for you boaters salivating at the prospect of buying a 1,400 horsepower engine for $100, not everything in boating during the Kaiser era was so cheap.  For example, Henry Kaiser’s cost for a 12-volt submersible, automatic bilge pump was $45.50 ($535) in 1949; these pumps can be purchased much more cheaply today!

 

If 12 cylinders are great, then 24 cylinders must be even better, right?  There was an even more powerful version of the Allison V-1710, the Allison V-3420, which was essentially two 1710’s attached at the crankshaft.  Known as the Allison W model, this monster has 24 cylinders, 3,420 cubic inches and a horsepower rating of about 3,000 horsepower. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

These engines were produced near the end of the War and only about 100 were made at a cost to the Government of more than $50,000 ($998,567) each.  After the War, Kaiser acquired several of these engines for an average cost of $325 each ($3,819) each. Despite having two times the horsepower of the V-1710 Allison, this engine also had more than twice the weight.  So, despite the promise of all that horsepower, the combination of scarcity and weight limited this engine’s success in hydroplane racing.

 

By 1949, Allison engines were completely dominating unlimited hydroplane racing.  At that point, every lap, heat, and race record in Gold Cup, President’s Cup, and Harmsworth Trophy competition (the biggest prizes in boat racing as we will see later) were held by Allison engines.

 

Rolls Royce Engines:  The Rolls Royce Merlin engine is a 12-cylinder, 60 degree banked, liquid cooled, two-stage supercharged engine with 1,650 cubic inches, rated at 1,500 horsepower.   These engines were designed and produced by Rolls Royce Limited for wartime use.  Because of the potential risk to Rolls Royce factories from German bombing and the prospect of an invasion, Rolls Royce teamed up with Packard Automobile Company to produce a variant of the Merlin, known as the Packard V-1650-7, to be built in the United States.  The two-stage supercharger boosted horsepower beyond that of the Allison V-1710 and allowed aircraft equipped with Merlin’s to operate at higher altitude.  Probably the most famous U.S. WW II fighter, the P-51 Mustang, was powered by the Packard version of the Merlin, while the British Spitfire was powered by the Merlin. 

 

Rolls Royce also produced a non-supercharged version of the Merlin, known as the Meteor, which was used to power tanks and other military vehicles.  Meteors found their way into boats after the War, but not nearly in the numbers of Allison’s and Merlin’s.  Together, Allison’s and Rolls Royce Merlin’s completely dominated unlimited hydroplane racing from after WW II until the mid-1970’s when turbine engines began to replace piston-driven engines.  By the mid-1980’s, turbine engines dominated the sport.  If you would like to hear the sound of one of these WW II aircraft engines start up and run, scan the QR code below.

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We hope this brief background on hull and engine technology will provide useful context for a better understanding of boat racing history at Lake Tahoe and on the national level.