TBPNews #37 - March 15, 2003.
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>>>>>> Tunnel Boat Performance News >>>>>>>>>>>>>>
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In this issue: 
1) Merc extends QuickParts to all 50 states
2) Inflatables crack top 20 popularity list 
3) NEW - Powerboat Links Pages!
4) NEW - High Performance Powerboating Apparel
5) 'Offshore' magazine - Save 53%!
6) POWERBOAT Books - 'The Offshore Grand Prix: There's No Turning Back'
7) Feature Article - "The Short Course on Tunnel Boats"
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1) Merc extends QuickParts to all 50 states 

Mercury Marine has expanded its QuickParts Distributor program, making it available in all 50 states. The company chose Land N Sea Distributing Inc. to service the South-Central United States, including New Mexico, Texas, Louisiana and Mississippi.  QuickParts began as a pilot program in 1999, when Mercury launched it in four test markets throughout the United States.
From its 10 U.S. distribution warehouses, Land N Sea says it can cover the market with same-day or next-day delivery.
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2)  Inflatables crack top 20 list

The emergence of two of its brands on the top 20 list of a popular Internet boating site is exciting news for the inflatables segment.  This breakthrough for inflatables (RIB's, ZapCat, etc.) follows the release of the most recent (February) list of top 20 consumer searches on the boats.com site. Zodiac finished fourth and Avon was No. 11 in numbers of consumer searches. Zodiac North America distributes both brands.  It seems that more consumers are recognizing the advantage of inflatable boats.  Check out our links to Inflatables sites:  http://www.aeromarineresearch.com/pages/
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3) NEW - Powerboat Links Pages!

More every week!  Over 1000 Performance Boating Links!  Well organized in easy-to-find categories.  Use the Powerboat Links to find everything you need for high performance powerboating.  ADD YOUR LINK to Powerboat Links, so that everyone else can find you!

http://www.aeromarineresearch.com/pages/
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4) NEW - AeroMarine High Performance Powerboating Apparel

Now available at great prices...High Performance Powerboating Apparel.  Wear and display your passion for high performance powerboating everywhere.  Pullovers, vests, sweatshirts, tee-shirts, baby doll shirts, race travel bags, coffee mugs, coasters, wall clocks, mousepads.  All with high performance powerboating graphics.  Check them out at: 

http://www.cafeshops.com/cp/store.aspx?s=AeroMarine
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5) 'Offshore' magazine - Save 53%!

We have obtained great deals on Powerboat magazine subscriptions.  This month we have a great deal on the popular 'Family & Performance Boating ' magazine. 
 
'Offshore' magazine - A regional magazine with features and regular columns dealing primarily with boating topics (like cruising, destinations, personal boating experiences, fishing stories, and marina reviews). The editorial also reflects the water-oriented lifestyle of the region.  12 issues; Published: Monthly ; Cover Rate: $42.00; Our Rate: $19.95 (53% savings!)

Get yours now at: http://www.aeromarineresearch.com/boating%20magazines%20discounts.html
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6) High Performance POWERBOAT Books - 'The Offshore Grand Prix: There's No Turning Back'

We have obtained great deals on Powerboating design and history books. This month.... 

The Offshore Grand Prix: There's No Turning Back' - Author Jill Berg introduces the reader to the dynamic sport of Class I offshore powerboat racing - the international racing sport of rich daredevils and thrillseekers. While following the day-to-day race activities of Norway's Ugland Race Team, readers learn about the basic technology and safety measures involved in the sport and get a sneak peak at the behind the scenes activities competitors enjoy during the seven month season.  Hardcover: 117 pages ; Dimensions (in inches): 0.75 x 8.75 x 11.00; ISBN: 1873295456; Price: $29.95 

http://www.aeromarineresearch.com/boating%20books%20discounts.html
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7) Feature Article - "The Short Course on Tunnel Boats"

*** The Short Course On Tunnel Boats, Part I (by Jim Russell, P.Eng.)

- Where did tunnel boats come from?  
Sir John Thornecroft designed a hollow-bottomed craft in the early 1870's that resembled what we modern boating enthusiasts would call a sea sled.  In 1908, he designed a boat of a similar configuration, combining the features of the sea sled and a cathedral type hull form.  

- A Canadian might have been first:
Although not the first boat boasting a tunneled-hull, the Hickman 'sea sled' was probably one of the first of this type of craft to attain higher speeds.  A native of Nova Scotia, Canada, Albert Hickman patented his design of a partially tunneled hull in 1914.  The sea sled was an inverted Vee hull in the fore section reducing to a flat transom and a tunnel between the two 'hulls'.  When at planing speed, the air trapped in the tunnel finds it difficult to escape, since the tunnel is below the water level at the transom.  A certain amount of lift was realized from this 'trap' or high-pressure pocket.  This could also be dangerous however, as at very high speed, the boat could become totally airborne and extremely unstable (since there would be no boat left in the water!) 

- Switzer Wings were fast, but couldnt corner:
The first symmetrical twin-hulled boats in their original design form (two vee-shaped hulls connected by a wing-shaped body) began with Dave & Bob Switzers Wing in 1958.  Other versions were popular for a number of years.  The original concept had the problem of turbulent water, or air/water mixture in the area of the centrally located propeller.  

- Two engines solve the Tunnels cavitation problem: 
By 1962, outboard power had increased to 100 horsepower and symmetrically-hulled craft with two engines mounted individually aft of each hull were established in competition.  The ultimate dual engine installation on the Switzer Wing-type design arrangement solved the propeller cavitation problem, but the spray into the tunnel was still an added resistance.  Also, the very tight cornering ability of the original 'trip-chined' sea sled, (although admittedly somewhat unpredictably hair-raising), was forfeited.  The Wing design was notorious for using more than it's share of the race course for cornering (Mark will recall racing against these designs) - and the tight, even walled-in closed courses often seen in European racing proved some additional navigational problems for this type of bottoms design.  

- Catamaran design hits the race course: 
Carl Kiekhaufer experimented with these hulls at Lake X before he presented them to the race course.  Designs such as the 'Switzer Wing' enjoyed some racing success and showed, as the name might suggest, recognition of the growing importance of the aerodynamic effects on a boat.

- Asymmetrical hulls by Shultz & Molinari turn as if on railway tracks: 
The design of asymmetrical hull shapes began around 1961.  By providing each hull with a keel and only one chine along the outer edge of the boat, the water escaping around the chine was greatly reduced and spray into the tunnel was eliminated!  More importantly, these chines made gave these hulls the ability to turn on a dime.  Among the first creators, in the early 1960s were Dieter Schultz of Austria and Angelo Molinari of Italy.  

- The Stuff: 
The first hulls from Schultz had a tendency to stuff unexpectedly, due to a normally low angle of attack and somewhat unstable center of lift with a large bow.

- The Blow-Over: 
Molinari seemed to have solved the deadly stuffing problem by designing an upswing (called a banana Molinari) of the tunnel roof at the front of the hull.  But this relocation of the aerodynamic center further fore caused frequent blow-overs.

- The Pickle-Fork: 
The tunnel hulls first introduced to the racing circuit were of the 'full' bow design, provided a great deal of lift - and were unbelievably fast!  The tunnel roofs were even concave shaped in the fore, to 'catch' the wind and provide added lift.  The major detriment of this feature was though, that the aerodynamic center (or center of lift) is located very near the bow of the boat, causing the severe instability problems that we have already noted to be dreaded during these times.  The pickle-fork design cut back the wing section aft of the protruding sponsons.  The center of lift is moved aft by a significant amount, closer to the actual CG of the boat - and the stability problem is greatly reduced!  

- Finally, Acceptance! 
In 1970 the UIM published acceptance of the tunnel hull by introducing rule changes allowing unrestricted hull design.  In the next few years, a multitude of design innovations flooded the circuit-racing scene, and the rapid advancement of the tunnel hull design was under way.  

OK...that is enough for this issue.  Next time we will have a "short course" look at the design of the tunnel boat.  (The complete history and design of tunnel hulls is detailed in Russell's book "Secrets of Tunnel Boat Design").

http://www.aeromarineresearch.com/stbd2.html
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See you next time!

/Jimboat