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Old 08 September 2006, 05:15   #21
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Quote:
Originally Posted by 7075T6
Bought the 900 RS in june with 2x275 Verado. Nice boat but dissapointed with the performance as delivered.57 knots with 10 pers at 6300 rpm. Also very unstable at around 50 kn. Possible to run through it but feels strange. Seems to be wrong propellers-Vensura 23". Will try 26" Bravo One this weekend and raise the engines. No help from the dealer here in Sweden."-You must use the trim..." Hu? Should have bought the Ring 9,5 m that Petrov offered...
Sorry to hear of this. I was not aware of these details but do know your rib as I was fortunate to be in Poland at the time of the first testing on the water. I am told this was the first Parker 900RS fitted with twin verado 275 and our guys were following the then installation instructions from Marine Power. We now know these engines should have been fitted higher ect.
Peder our Swedish distributor is currently abroad and this is probably why you are saying no help from the dealer. Peder is not that kind of guy who neglects his customers. I am confident he will be contacting you on his return
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Old 08 September 2006, 13:01   #22
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There is a Revenger 34 here in Norway that i rigged with twin 275 Verado's and we got 61 knots with i think it was 23 or 24 Revelution 4 props, the engines are mounted 15,5 cm over the kell and we use 25' leg engines on an boat that was built for 30' leg engines, we allso have a revenger 27 with a Verado 250 and here the engines is mounted 13,5 cm over the kell we allways run 4 blade props either revelution 4 or bravo one. the revelution props give more top speed on empty boat, but the speed is the same on the bravo and the revelution when we have 18 peoples and 750 liter of fuel onboard the revenger 34.

We allso tried mirage plus props on the Revenger 34, but they cavitated so much that we hardly was able to get the boat on plane.
Raise your engines and the boat would be mucher better to drive and you will gain more speed.
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Old 08 September 2006, 15:17   #23
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57 knots...

Vensura 23"-2 pers 6300 rpm 57 kn...
Vensura 232 12 pers 6350 rpm 57 kn...
Bravo One 26" 2 pers 5400 rpm 57 kn...
Bravo One 26" 10 pers 5400 rpm 57 kn...
Bravo One 26" 2 pers engines raised max 5200 rpm 57 kn!!
Seems to be a wall of glass at 57 knots. The boat handles much better with the higher engine mounts.Really good, tight turns at 30-35 kn in choppy water. We had some 20-22 m/s winds today and the engines had no problem with cooling or grip in turns.The only problem is speed-57 kn...
I will try some 24" Bravos and see if the 57 kn barrier can be broken next week. For the moment it feels like I am doing the R&D that the Parker boys should have done before delivery. And Andre-I will send You a mail about your dealers "customer care". (I am one of the Top 10 Toyota -dealers in Sweden and know how it should be done)
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Old 08 September 2006, 15:51   #24
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The Revenger 34 topp speed with 24 bravo one is 56 knots light load and 61 knots with the same pitch revelution 4, when it comes to raising the engines the verados could go 2-3 cm higher then other outboards as the prop is 10 cm further back from the transom then other outboards.
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Old 08 September 2006, 15:59   #25
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Since your rpm is 6350 with 23' vensura you should go down one pitch when switching to 4 blade props, so to get the correct rpm on the engines i would have tried 22'-21' pitch bravo one or revelution 4, when you get the correct rpm with 4 blade props, i would switch to the next pitch higher prop and get them lab finished, the lab finish would give you 200-300 more rpm's than a stock prop at the same pitch and possible more speed.
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Old 08 September 2006, 16:12   #26
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You have 11,58 % slip with the vensura 23 prop and 8,75 % slip with the bravo prop. If you have a bravo one 22 and still have 8,75% slip you would have 57,16 knots top speed, with 5 % slip you would have 59,51 knots.

5 % slip is very low, the only solution seems to be raising the engines much more and make them spin more rpm's without the slip % going up.

The greek Revenger dealer have a Revenger 29 that goes over 70 knots, but they run the engines quit high and the engine is merc 250 xs with race gearcase
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Old 08 September 2006, 16:20   #27
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57 kn..

The Vensura is a 4-blade. The Bravo One has very low slip compared to the Vensura.At 3500 rpm the Vensura 23" made 30 kn-Bravo One 26"-36 kn.
With the engines raised max(you can see two holes above the transom) the Bravo One 26" makes 43 kn at 4000 rpm and 57 at 5200. Thanks for the info.
Maybe the Rev 4 is the solution to get over 60 kn.
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Old 08 September 2006, 16:40   #28
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You should measure the transom lenght from top transom edge to bottom of the hull at the center of the engine, if you measure 25 ' the engines are only 9-10 cm over the keel when mounted at the lowest hole, you could raise the engine 3-5 cm more than that without any problems when it comes to slip %. the way to do that is to make/buy a spacer plate to space the engines further back or plate that allows you to raise the engines higher, or you could mount the engines closer than 66 cm center 2 center. most boat building companys are very conservative when they make the hight of the transom and think that people mount their engines with cav. plate at the same hight as the kell.
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Old 08 September 2006, 16:45   #29
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Quote:
Originally Posted by searafting.no
You should measure the transom lenght from top transom edge to bottom of the hull at the center of the engine, if you measure 25 ' the engines are only 9-10 cm over the keel when mounted at the lowest hole, you could raise the engine 3-5 cm more than that without any problems when it comes to slip %. the way to do that is to make/buy a spacer plate to space the engines further back or plate that allows you to raise the engines higher, or you could mount the engines closer than 66 cm center 2 center. most boat building companys are very conservative when they make the hight of the transom and think that people mount their engines with cav. plate at the same hight as the kell.
As I understand it , only 2/3rds of that prop should be in the water
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Old 08 September 2006, 16:45   #30
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Do you guys mean you are running the engines much higher than the normal arrangement of the cavitation plate being level with the base of the hull? How does that work then?

Not trying to start an argument or anything, just curious as to why it works
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