Cattitude

Bought the boat last Sept, twin 496 HO's with boxes, std bravos, 1.5 ratio. no tab, x is about 3/4 above the lowest part of the sponson

The 30" Bravo ones were canned in favor of 30" maximus, pulled the ventilation plugs and planing was much better, cruise improved, more digits for less RPM. fast forward to spring, 1" xr shorties go on (Eliminator cautioned me that if I went higher I may need a tab to get on plane), tested briefly yesterday with 32" maximus, planning was more difficult, but still better than with stock bravo 30's, 3/4 gas, 2 peeps and some junk stored in the bow, hit 92 gps on relatively flat water on the limiter- but could've been a bit overtrimmed too

I'm feeling 95 is there easy on a good day, light load but still a fully recreational boat. a few more digits will come on that one miracle day I'm sure. I know the light layup/no cabin boat did 103 in perfect conditionsd with Jerry May driving, I'm happy to be getting in the neighborhood.

Boat feels real solid and connected at speeds, feels like the cruise is happier at 55ish where before cruise was happier in the low 60's- maybe more stern lift as the props still have the diffusers (the 30" maximus had 1'2" of diffuser gone when I bought them)

I should add that 85-88 was the top speed with the 4 blades and that the results are with 1125 feet of elevation- more tinkering will follow and will be reported- for the time being need to chase down a water flow issue with the starboard engine

anyway- sharing the good results hoping it'll help others

jdnca1

I don't know about the 30' daytonas, but the 28's and 33's really like Hydromotive P5X props, turning in. I think you are running pretty good with the power and loads you described.

MikaylaHunterCig

I also don't know much about the 30' Daytona but my 06 28' w/ twin 496 power will run 104 w/ stock bravo 30's / imco 1" shorties. I had labbed 30's on it but was banging the rev limiters.

My boat does have a tunnel tab and i use it to get on plane- however i don't feel these boats are abnormal as to there up on plane character when comparing to other models with the same drive set up.

Dave

pstorti

iTrader: (2)

My 28 with non HO 496's has hit 91 with 29" P5x's I tried 28" maximus they were incredible out of the hole and at cruise but I couldn't spin them past 4500 rpm so they only went 81. Regular bravo 30" gave me the same top end as the 29" P5x but they blowout badly coming out and the cruising speeds were lower. On my boat all the lab props I tried did nothing but spin more rpm's, when I ran the numbers the lab props had higher slip numbers so for my boat they don't work.

I tested the following props on my boat:
Hydromotive:
P5x 29" (final choice)
P5 labbed couldn't get boat on plane (no diffuser ring)
P4x 29" (best top end 89.6 on test day but not worth it otherwise)

Mercury:
Bravo 30 good all around better handling than 5 blades but couldn't match efficiency
Bravo 28 acceleration not much diff than 30's and 80mph top end
Bravo 30 Labbed worse than regular 30's no improvement in speed at any rpm
Bravo 28 labbed same story.
Maximus 28 incredible bite boat planed at 13mph (it wasn't level but it was hooked up) awesome holeshot and cruise no top end.

I didn't try a labbed maximus because I really don't like labbed props they cost twice as much and if you hit anything they are junk. I'm sure I have hit a few floating coconuts over the years and the regular props are unfazed labbed props would throw a blade. I have some excel spreadsheets with the data and graphs if anyone is interested. I made up some blank test sheets with the same parameters Powerboat tests for so I could compare numbers more accurately. I'll email them to anyone who wants them.

Thanks to Throttle-Up and Cast-A-Line Marine for the use of all the props!

Oh and my boat is a 2002 XZ drives that look like the shafts are about 1" above the bottom of the boat no boxes.

stangjeeper

congrats on the numbers Ken,
Im sure there is a lil more there and youll find it in time.

Cattitude

thanks guys...

Mikayla- there is a customer here that's seeing 106gps from his 2005 28 with 496HO's, I need to go study his setup- his number comes from a different lake with less elevation. Are you getting 104 on Havasu or at sea level? Also, would be useful to know what your x is, sounds like no boxes?

Paul, could be your drives are a bit deepr or maybe pulling the vent holes has the airation helping to loosen up the blades a little at top end.

Does anybody have ideas about what Imco cavitation plates would do?- I don't have them now. showers are plumbed directly to side of case.

jdnca1

The Imco cavitation plates really help with planing from what I have seen.

pstorti

iTrader: (2)

Ken I'm not sure I understand what you mean...deeper than what? They are deeper than the newer 28's for sure if I put on 2" shorties I would probably gain 4-6 mph top end but it would be hard to get on plane. I was going to do stellings boxes to get 2" higher but it doesn't seem worth the expense for a few mph. Also my props don't have vent holes.

Trim wise my top end is best when the rooster tail height is about eye level when I turn around. If you are having trouble reaching max rpm overtrim a little to get the revs up and slowly bring the trim back down the revs should stay up while the speed increases.

I talked to a Mercury guy at the boat show about the cavitation plates they use on XR sportmasters and if they would help me get on plane easier. he said that those plates take the place of the missing cavitation plate and wouldn't make a difference in my application. I haven't seen the Imco ones maybe they are bigger. He also said that the real purpose of those is to prevent the props from sucking air from the surface which I guess makes sense.

I don't understand how a 32 skater can get on plane with no bowrise but the daytonas have lots of trouble, must be the pod...

Cattitude

Paul- I meant deeper relative to the bottom of your sponsons.

When you get a shorty, there is no cavitation plate in the casting- but IMCO offers bolt ons that will help get on plane- so I'm told-= so theoretically- they would not help a stock lower but may help a guy with a shorty- prop wash will push up on them so it has to help somewhat.

I could be all wet but I think the longer cats have more nose weight to help break the bow over- no brands or center pods involved

In my case, when I bought the boat, I knew i wanted to upgrade to 1.25" shafts, so I just held out til I scrounged some 1" shorties, the stock lowers will be in the classifieds soon

pstorti

iTrader: (2)

Ken from what the Mercury guy said you will benefit from the bolt on plate, its not that the wash pushes up on the plate. The plate prevents the action of the prop from creating an air path to the surface. Without the cav plate in high x-dim boats when the prop starts to spin it creates suction that draws air from the surface and causes the prop to blowout. The merc part will probably fit as well.

Did you have a chance to try a P5x yet?