TBPNews #28 - October 17, 2002
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In this issue: 
1) Bombardier/OMC - New plant saves old brand names 
2) Discounts on 'Hot Boat' magazine
3) Elements of Boat Strength' book deal
4) Feature Article: 10 Tips for Increased Performance
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1) Bombardier/OMC - New plant saves old brand names

How can a company rebuild a failed manufacturing operation that has been rapidly bringing down two of the best-known names in outboard engines--and do it within a remarkable 78 days? Such a feat is possible if you have the resources and talents of Bombardier, the $14-billion-a-year Montreal maker of business jets, railcars, and snowmobiles. 

Bombardier faced a daunting challenge early last year when it bought the stumbling manufacturing operations of Outboard Marine Corp. (OMC), the maker of Evinrude and Johnson outboard engines, for $55 million. The quality of the engines had declined and dealers were deserting in droves. OMC's share of the $2-billion-a-year-plus outboard-engine market had plummeted from 55% in 1995 to 23% in 2000. The powerful Ficht fuel-injection technology that OMC had developed with a German company, hoping to gain a competitive advantage, had turned into an albatross because manufacturing couldn't meet the demanding tolerances.   

See the full article in Fortune magazine at: http://www.fortune.com/indexw.jhtml?channel=artcol.jhtml&doc_id=209011
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2) 50%+ DISCOUNT on all power boating magazines!  

We have obtained great deals on Powerboat magazine subscriptions.  Check out your favorites at: http://www.aeromarineresearch.com/boating%20magazines%20discounts.html
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3) High Performance POWERBOAT Books - The Elements of Boat Strength: For Builders, Designers & Owners

We have obtained great deals on Powerboating design and history books.
http://www.aeromarineresearch.com/boating%20magazines%20discounts.html
The Elements of Boat Strength includes a method of assessing structural strength in the context of the modern marine environment.  Acclaimed author and naval architect Dave Gerr created this unique system of easy-to-use scantling rules and rules-of-thumb for calculating the necessary dimensions, or scantlings, of hulls, decks, and other boat parts, whether built of fiberglass, wood, wood-epoxy composite, steel, or aluminum. In addition to the rules themselves, The Elements of Boat Strength offers their context: an in-depth, plain-English discussion of boat building materials, methods, and practices that will guide you through all aspects of boat construction.  With this book, an inexpensive scientific calculator, and a pad of paper, you'll be able to design and specify all the components necessary to build a sound, long-lasting, rugged vessel. 
http://www.aeromarineresearch.com/boating%20books%20discounts.html
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4)  TBPNews Feature Article - 10 Tips for Increased Performance

If you don't want to make expensive modifications to your hull or engine or setup (Secrets of Tunnel boat Design book and Tunnel Boat Design Software can make it easy to see the results of these best modifications), then here are some tips for getting the most performance from your current setup.

1.  Keep it Clean - Your boat bottom will be quickest if it is perfectly smooth.  Dirt and slime buildup will slow you down.  Clean the bottom with a strong cleaner.  Wet sand any tough bumps in the running surface with 400-600 grit paper.  You don't need wax (in fact it can, in some circumstances, slow you down.)

2.  Get your bottom straight - Using a long straightedge, check for any irregularities that can scrub any speed that we've already got.  If you notice distortion, check for structural damage inside the hull.  Any low spots need to be filled and gel coated until completely smooth and true.  Be aware that some boats are manufactured with a "hook", or recessed area in the bottom; or a "rocker", a raised area on the hull running surface.  Contact the dealer or manufacturer to see if there are any designed features that you shouldn't disturb.

3.  Perfect your prop - the prop can be the most important piece of the speed puzzle.  Be sure that the design of the prop fits the characteristics of your boat, and the performance attributes that you desire.  Any nicks, chips, dings, or bent blades will really hurt performance, so have them repaired.  

The right prop selection can offer speed and handling gains unmatched by any boat or engine modifications.  Every rig is different and every prop is different, however, so the combinations are endless.  There are a few "rules of thumb" that often apply, though, and can offer a starting point for selection.  

First, high rake, round-ear propellers will work more effectively on the majority of recreational hulls.  Second, the lower the power-to-weight ratio (of your hull), the more positive rake and tip cup is needed to maintain an efficient ride attitude.  Third, slower (50 to 65 mph) rigs will run better with thru-hub exhaust and three or four highly raked, highly cupped blades.  As speeds increase, the over-hub, race-style props will perform at higher levels.  Forth, Cleaver props with lower rake angles will work well on rigs that need little or no added lift from the prop; larger, dual-engine catamarans are the best hulls for these types of propellers.   Fifth, High-rake, round-ear props are best for hulls that require bow and stern lift - even tunnel hulls and power-cats that are asked to carry weight.   There is software you can use to help select the best prop for your hull and predict speed for alternate props (PropWorks2 software).

4.  Motor Height - Engine height is critical to speed.  Most performance boats run best when the prop shaft is in line with, or just above the bottom running surface of the hull.  To check this, trim the engine to a point where the prop shaft is parallel to the boat's bottom.  Now take a straight edge and hold it up to the bottom of the boat.  Typically, it should intersect the lower unit just below the prop shaft, meaning the prop shaft is just above the bottom of the boat.  You can experiment by raising the motor by 1 mounting hole at a time on the transom bracket.

5.  Jack plates and setback - You can make motor height alterations more easily and more accurately by installing a "jack plate" on your boat.  A jack plate will electrically or hydraulically or manually raise or lower the engine height on your transom.  Start out with the engine lower in the water and then raise it while under way.  Make small changes at a time, and keep records of the results.  Raising the motor will reduce drag and increase top speed - as long as you still have good prop bite.  An engine setback bracket can move the engine aft of the transom.  Some setups will benefit of adding 6" to 24" of setback.  This can allow the propeller to work in water that is cleaner, and also provides more influence on bow lift due to the leverage of the setback.   A rule of thumb is that smaller, lighter boats with plenty of power need less setback, while longer, heavier hulls with similar power need more.

6  Check your water - When raising the engine mounting height to increase speed, or a setback plate/bracket, you must be careful to ensure that the motor is still getting sufficient cooling water intake flow.  A water pressure gauge is the best method of monitoring water flow, and is not expensive.  Loss of water pressure at full speed for even a brief period can cause permanent and expensive damage to your motor.

7.  Nosecones - Another performance enhancing add-on to consider - particularly when you use a jack plate or setback bracket - is a low water pickup or nosecone.  The low water pickup should be used when water pressure is insufficient.  The nosecone can help with lower hydrodynamic drag, and prevention of "blowout" when speeds above 70 mph are required.  These devices are usually epoxied or welded to the front of the lower unit bullet.  The low water pickup extends the intake of water-cooling flow inlet to lower on the gearcase.  The nosecone extends the length of the bullet, allowing a more hydrodynamically efficient shape, and also moves the water pickup to the front of the nosecone.  If your rig needs excessive trim to achieve top speed or it is currently suffering from premature prop ventilation, then a nosecone would help.  Along with nosecones go torque tabs, those little add-on skeg wedges that not only help our gearcase track straighter, but also keep you from big-time arm therapy after a day on the water.  Torque tabs simply rivet onto the starboard, rear of the skeg.

8.  Better breathing - One of the easiest ways to let your engine breathe better is with a set of aftermarket reed valves.  These can allow the air/fuel mixture to enter the engine combustion chamber more efficiently.  Reed valves that are more sensitive to vacuum and pressure changes can increase the ease at which our engine breathes at both acceleration speed and top speed.   Stock stainless reeds can't properly cover the modern 2-stroke's wide rpm band efficiently, particularly at the low and high-end of the power band.  Two-stage reeds operate more effectively because the top reed (thinner and smaller) opens more easily and at lower speeds than the (thicker) bottom reed.  At higher Rpms, the bottom reed opens and allows the full charge through.  Performance gains are of 150-200 rpm can be recognized, along with better idling qualities and more throttle response at all speeds.  Using ceramic or fiber reeds instead of OEM metal reeds are also much safer, causing less damage to the engine if they are to break for some reason.

9.   More air - Aftermarket louvers for the engine cowl will do wonders for performance.  Land & Sea or Bob's Machine Shop have good louvers that are reasonably priced.  Before you install louvers, realize that it may be necessary to re-jet the carburetors to take best advantage of the additional airflow.  

10.  Check for Optimum performance - At some time in your "improvement" program, you should research the performance that can be expected from your hull and engine setup.  A good way is to ask allot of questions of your dealer, and of others that have had success with a similar hull setup.  There's no point in making allot of changes to your boat and setup, only to find that your hull wasn't ever designed to see the speeds you're expecting.  (There is software that will help analyze performance and stability changes resulting from any number of design and setup changes you are considering.  It can be much less expensive to find out before spending the money, that your desired change may not give you the expected results.)

A final recommendation...if you are going to drive your boat at high speeds, then be sure to install the necessary safety equipment.  These include dual-cable or hydraulic steering, rigid motor mounts, positive ignition "kill-switch" cutoff, foot-controlled throttle pedal and steering wheel mounted (or floor mounted) engine trim buttons.  Next issue will discuss all of these features!

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See you next time!

/Jimboat
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