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Does the prop I use affect me

 
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Perry D
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PostPosted: Sun Oct 29, 2006 7:58 am    Post subject: Does the prop I use affect me Reply with quote

Sking season is over heere in Michigan so I'm asking does the prop I use affect the boats perfance specifcally for sking?
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Werk



Joined: 17 Oct 2006
Posts: 11

PostPosted: Mon Oct 30, 2006 6:30 pm    Post subject: Reply with quote

Perry,

The best propeller size for your boat and engine combination is based on the recommended operating range at wide open throttle (w.o.t.) for your engine, which you will find in your engine operator's manual.

The goal in prop selection is to determine what propeller style and size will maximize performance for your boat, while allowing your engine to operate in the recommended RPM range. The correct propeller will prevent the engine from over-revving, yet allow it to reach the minimum RPM where maximum horsepower is produced.

Run the boat/motor at w.o.t. under normal operating load to determine the maximum RPM you are able to obtain. Adjust the motor trim angle for the optimum performance. If during this test, you begin to exceed the maximum rated RPM of the engine, reduce throttle setting to a position where maximum RPM is not exceeded.

If your test results in your being able to over-rev the engine, you need to increase the pitch of the propeller. Increasing the pitch increment by 1" will result in approximately a 200 RPM drop. If your testing shows, however, that you are only able to obtain a RPM somewhat lower than the maximum rating given by your engine manufacturer, you would need to decrease pitch. Decreasing pitch would increase your RPM. Once your wide open throttle RPM falls within the recommended range of the engine manufacturer, you have a propeller that is suited correctly for your boat with respect to RPM.

If you use your boat for fishing, cruising and skiing, one prop probably won't do all three things equally well. It is best in circumstances like this to have two propellers; One to accommodate one set of circumstances and the other to perform best under the different load. It is imperative, however, that the wide open throttle RPM fall within the range specified by your engine manufacturer.
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Raleigh King
Hopkins Propeller
Marine Proptologist in training
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Paul
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PostPosted: Tue Oct 31, 2006 2:03 pm    Post subject: Great info Reply with quote

I am glad somebody put this info on the net!
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Werk



Joined: 17 Oct 2006
Posts: 11

PostPosted: Thu Nov 02, 2006 6:28 pm    Post subject: Reply with quote

thats what we are here for Wink
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Raleigh King
Hopkins Propeller
Marine Proptologist in training
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MARK
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PostPosted: Sun Nov 26, 2006 7:30 pm    Post subject: How to Buy a Water-ski Boat Reply with quote

The changing nature of boat design reflects how the sport has evolved over time. Skiers prefer small, soft wakes. Wakeboarders, on the other hand, want big wakes from which to launch aerial maneuvers. But when mom and dad are die-hard skiers, and the kids want to wakeboard-- and with $25,000 and more at stake--then what?
Instructions
STEP 1: Review your basic options. An inboard engine is the most powerful and is located in the boat's hull. Cheaper outboard engines clamp onto the transom. Inboard/outboard engines combine the power of an inboard with the maneuverability of an outboard. STEP 2: Understand the trade-offs between inboard engine types: STEP 3: A direct-drive engine is located mid-boat and sends power directly from the engine to the drive shaft to the propeller. Direct drives with their flat bottoms are preferred by skiers because they produce small wakes, and handle and track better. The flat hull, however, makes riding on choppy water a bouncy ride; and the engine, smack dab in the middle of the boat, uses up prime seating. STEP 4: V-drive boats have rear-mounted engines and a deep V hull that cuts through chop without a blink, but produce a large wake. Some feature ballast tanks that can be filled for even bigger wakes, making wakeboarders ecstatic, then drained again for skiers. The engine location allows for quieter, more sociable seating. Tow lines attach from a tower high above the cockpit. STEP 5: Meet in the middle. Recognizing the market's changing needs, boat builders have designed crossover boats. Mostly featuring direct-drive engines, these "all-event" boats have ballast tanks that hold up to 1,600 lbs (597 kg) with adjustable trim-plates. So fill it up and create monster wakes, or dial it back down for the skiers; one boat happily serves both camps. STEP 6: Investigate available amenities. Swim platforms make it easier to climb into the boat after a hard run, and overhead racks stow gear safely away. What To Look For
Engine type
Direct-drive or V-drive
Crossover boats
Amenities
Overall Tips & Warnings
Improved technology has boosted engines to over 300 horsepower. In the future, look for boats with new composite hull materials and engines that further reduce noise and water pollution.
The hull ventilation system prevents the buildup of explosive gasoline fumes. Make sure it works before operating the boat.
If you're buying a used boat, hire a marine surveyor to perform an inspection. This service costs several hundred dollars but will reveal any potentially disastrous problems. You need to be sure the engine is functioning and the hull is sound.
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