stock sportmasters.
Platinum Member
02-11-2006, 10:35 AM
#2
Offshoreonly Advertiser
Offshoreonly Advertiser
Re: stock sportmasters.
Most people think sporty's were designed to be sleek and make you go faster. Correct, only if used properly. The reality is, the additional metal in the water can slow you down due to drag.
When the first crescent leading edge gear cases were made, they were actually designed to prevent blow out. Crabbing of the gear case can cause a ventilating bubble, that if allowed to grow long enough, will attack the high pressure side of the propeller blades causing the propeller to blow out. Since this takes alot of speed to develop, the blow out situation can be dangerous.
While I was at Mercury in earlier days, we used to tell people you needed to be concerned about blow out above 80 mph with standard gear cases. We learned there was alot more to it than just the gear case. The big variable was the dynamics of the hull. Some applications could run well into triple digits with standard cases and never experience the ill affect of blow out. Any body running into the 80's with outboards still needs to be aware of the possibility. But, Bravo drive cases are capable of higher speeds without blowing out.
So, to combat the down side of the longer case and extra metal in the water, the cases really need to run at extra high "X" dimensions. Keeping the case high and surfacing the props allows these designs to do what they were intended to do, make you go faster. So what you have is a bigger overall case with less material in the water than the smaller case. So here in lies the dilemma. Many boats can't carry the bow with the props on the surface. Bigger deeper V hulls may need the props buried to run well. So when considering sportmaster style gear case you need to ask yourself a few important questions..........
Self, is my boat going to run into and above the 80 mph mark? Also, does my boat need alot of bow lift? Can it fly the front end at speed without too much trim?
If you answered yes, no, yes, you may be the perfect candidate for a sportmaster style gear case.
When the first crescent leading edge gear cases were made, they were actually designed to prevent blow out. Crabbing of the gear case can cause a ventilating bubble, that if allowed to grow long enough, will attack the high pressure side of the propeller blades causing the propeller to blow out. Since this takes alot of speed to develop, the blow out situation can be dangerous.
While I was at Mercury in earlier days, we used to tell people you needed to be concerned about blow out above 80 mph with standard gear cases. We learned there was alot more to it than just the gear case. The big variable was the dynamics of the hull. Some applications could run well into triple digits with standard cases and never experience the ill affect of blow out. Any body running into the 80's with outboards still needs to be aware of the possibility. But, Bravo drive cases are capable of higher speeds without blowing out.
So, to combat the down side of the longer case and extra metal in the water, the cases really need to run at extra high "X" dimensions. Keeping the case high and surfacing the props allows these designs to do what they were intended to do, make you go faster. So what you have is a bigger overall case with less material in the water than the smaller case. So here in lies the dilemma. Many boats can't carry the bow with the props on the surface. Bigger deeper V hulls may need the props buried to run well. So when considering sportmaster style gear case you need to ask yourself a few important questions..........
Self, is my boat going to run into and above the 80 mph mark? Also, does my boat need alot of bow lift? Can it fly the front end at speed without too much trim?
If you answered yes, no, yes, you may be the perfect candidate for a sportmaster style gear case.
__________________
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
02-11-2006, 10:40 AM
#3
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Location: Paducah, KY
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Re: stock sportmasters.
Originally Posted by bbladesprops
Most people think sporty's were designed to be sleek and make you go faster. Correct, only if used properly. The reality is, the additional metal in the water can slow you down due to drag.
When the first crescent leading edge gear cases were made, they were actually designed to prevent blow out. Crabbing of the gear case can cause a ventilating bubble, that if allowed to grow long enough, will attack the high pressure side of the propeller blades causing the propeller to blow out. Since this takes alot of speed to develop, the blow out situation can be dangerous.
While I was at Mercury in earlier days, we used to tell people you needed to be concerned about blow out above 80 mph with standard gear cases. We learned there was alot more to it than just the gear case. The big variable was the dynamics of the hull. Some applications could run well into triple digits with standard cases and never experience the ill affect of blow out. Any body running into the 80's with outboards still needs to be aware of the possibility. But, Bravo drive cases are capable of higher speeds without blowing out.
So, to combat the down side of the longer case and extra metal in the water, the cases really need to run at extra high "X" dimensions. Keeping the case high and surfacing the props allows these designs to do what they were intended to do, make you go faster. So what you have is a bigger overall case with less material in the water than the smaller case. So here in lies the dilemma. Many boats can't carry the bow with the props on the surface. Bigger deeper V hulls may need the props buried to run well. So when considering sportmaster style gear case you need to ask yourself a few important questions..........
Self, is my boat going to run into and above the 80 mph mark? Also, does my boat need alot of bow lift? Can it fly the front end at speed without too much trim?
If you answered yes, no, yes, you may be the perfect candidate for a sportmaster style gear case.
When the first crescent leading edge gear cases were made, they were actually designed to prevent blow out. Crabbing of the gear case can cause a ventilating bubble, that if allowed to grow long enough, will attack the high pressure side of the propeller blades causing the propeller to blow out. Since this takes alot of speed to develop, the blow out situation can be dangerous.
While I was at Mercury in earlier days, we used to tell people you needed to be concerned about blow out above 80 mph with standard gear cases. We learned there was alot more to it than just the gear case. The big variable was the dynamics of the hull. Some applications could run well into triple digits with standard cases and never experience the ill affect of blow out. Any body running into the 80's with outboards still needs to be aware of the possibility. But, Bravo drive cases are capable of higher speeds without blowing out.
So, to combat the down side of the longer case and extra metal in the water, the cases really need to run at extra high "X" dimensions. Keeping the case high and surfacing the props allows these designs to do what they were intended to do, make you go faster. So what you have is a bigger overall case with less material in the water than the smaller case. So here in lies the dilemma. Many boats can't carry the bow with the props on the surface. Bigger deeper V hulls may need the props buried to run well. So when considering sportmaster style gear case you need to ask yourself a few important questions..........
Self, is my boat going to run into and above the 80 mph mark? Also, does my boat need alot of bow lift? Can it fly the front end at speed without too much trim?
If you answered yes, no, yes, you may be the perfect candidate for a sportmaster style gear case.
best explination I have heard, thanks...
