Target slip Percentage
 

What is the optimum slippage for a Stock mirage+ or a labbed Bravo1 on a deep v 4000lbs 75 - 85mph range?

Re: Target slip Percentage
 

With the limited information you have give, under 15% could be acceptable. Of course you will need quite a bit of power to obtain those speeds. With enough power those speeds could be obtained at 18% for that matter.

If you get down to 12%, your probably doing quite well.

We would need to know more.

Re: Target slip Percentage
 

I was actually at 8% with the stock mirage+25 and 12% with the labbed Bravo1 26 on a efficient TRS drive with a Hydromotive mosecone. I have switched to a stock bravo1 drive and picked up 2" of drive height but now have a less hydrodynamic unit( no nose cone and water pickups on the sides) . I feel better knowing I am on the right track, Thanks. Is lower always better for slippage?

Re: Target slip Percentage
 

Typically, yes it is. Propeller efficiency translates into speed. So the greater the efficiency the better or more efficient the speeds. Eight percent is quite low for a 3B propeller. I would verify your data so that you can confirm your slip. The more accurate your data the better your prop fitting will be.

Julie

Re: Target slip Percentage
 

Ironman what was your boat faster with the Mirage plus or the Bravo 1 labbed? Also what type of boat is it?

Re: Target slip Percentage
 

Same speed and I also found the same speed with the Bravo drive as the heavier TRS drive with the same engine and prop Pantera 24 500hp 93 degrees full tank two on board flat water same rpm 75 at 5200rpm gps. Hope the 4 blade is better with the Bravo drive...

Re: Target slip Percentage
 

Hey Ironman,
To give you a little comparison:
1997 24' Super straight V, no pad, no step, just like your hull, maybe a little lighter.
1.5 Bravo drive with the prop shaft about 5" below the V.
Last year with about 360HP; 69-70mph at 4800rpm with a 25p Mirage + or a labbed 26p Bravo 1.
This year with about 440HP; 75-76mph at 4800rpm with a stock 28p Bravo 1.
I think the slip is around 12% with the Bravo 1.

Re: Target slip Percentage
 

I would have to agree that the numbers must be off. A mirage is almost never lower in slip than a bravo. Check that math!

Re: Target slip Percentage
 

8% is really efficient for a single engine boat. Nice job....... :drink:

Re: Target slip Percentage
 

Target slip will vary widely depending on the boat and set up. We have some single engine V race boats at 6-7% slip and some race cats at 3%. There are many factors which will affect slip. It takes time and set up changes to determine what the most efficient slip is for a particular application.

Matt

Re: Target slip Percentage
 

I found out why the Bravo drive and TRS run the same speed. The TRS had a lot more weight on the stern and 2.5" of leverage to lift the bow,Therefore the Mirage could really lift the bow before now it runs out of grip. The boat runs "wetter" now more level with the Bravo drive. I will try some bow lifting 4 blade props and see what happens after I straighten out the carb problems.

Re: Target slip Percentage
 

Carb problems??

Re: Target slip Percentage
 

Ironman you said the boat runs wetter now with the Bravo 1? How can it run wetter with the 4 blade and your still running the same speeds?

Re: Target slip Percentage
 

It ran wetter with the Mirage prop on the Bravo drive that the mirage prop on the TRS drive. I am guessing the speed was the same because any gains due to the the weight reduction were lost due to less leverage to lift the bow and the CG being a little farther foreward. I would speculate that with the cg foreward the boat will be faster in the rough water. The 4 blade hooks up really nicely and can really carry the bow of the boat. I could'nt get any real data as the rains came in before I could run it much.

Re: Target slip Percentage
 

Target slip depends on particular hull,my boat has most speed at about 20% slip,i can dig the drive in further and boat slows down,rpm's drop. I can go down in pitch and it still needs to be trimmed up to max with alot of slip to get max speed,Smitty