575 6.2L Ford ROUSHcharged Raptor vs 556hp Supercharged LSA ?

[The Hulk]

We have been surfing around 9.8mph with SG and I only have 550s in rear and a 1k bow bag which I put in center floor not in bow. 1 or 2 clicks up on wedge and I'm 2400-2600 depends on number of ppl 3-9 . I need to upgrade lockers to 750 or 900s so u can put the bow sac in the bow but I'll probably go with 750 so I can still fit a few jackets there and still acess the shower. Some rough calculations show we should go with a 15 x17 I'll post my math to get some feedback in nxt post

Edited August 26, 2015 by The Hulk

[shawndoggy]

wow that's really slow. your wave must be super short?

[saxton15]

Seriously, I run a 350 with a ton more weight than that and I surf 10.6-10.8 minimum

[DarkSide]

Hulk, you may also want to consider custom sacs. Mine are roughly 1200 and i still have use of my shower, rear tubs, and can fit a few jackets on top of the bags. A touch more money, but well worth it. A 247 is capable of such a great wave, and you have the power to move it.

Back to prop, i agree 15 x 17 is the ticket.

[DarkSide]

Seriously, I run a 350 with a ton more weight than that and I surf 10.6-10.8 minimum

Yes, and RPM is much higher as well. Trying to find a way to not only get it done, but how to get it done as efficiently as possible.

[shawndoggy]

Yes, and RPM is much higher as well. Trying to find a way to not only get it done, but how to get it done as efficiently as possible.

Man buys $125k 24' boat with triple axle trailer towed to lake with 1 ton dually, worries about saving $20 per trip.

[DarkSide]

Man buys $125k 24' boat with triple axle trailer towed to lake with 1 ton dually, worries about saving $20 per trip.

LOL, that isn't really the issue, the issue is i run out of gas. I have had my low fuel warning the last two outings. So gaining even a little efficiency would get me through the day. I just need 10% efficiency gain! Malibu made the tank 8 gallons smaller from '14 to '15.

It sucks deciding whether to go home or go to the marina. Not having to cut the last hour of the day because i am out of gas would be AWESOME!

And $20 is beer money...LOL

[shawndoggy]

LOL, that isn't really the issue, the issue is i run out of gas. I have had my low fuel warning the last two outings. So gaining even a little efficiency would get me through the day. I just need 10% efficiency gain! Malibu made the tank 8 gallons smaller from '14 to '15.

It sucks deciding whether to go home or go to the marina. Not having to cut the last hour of the day because i am out of gas would be AWESOME!

And $20 is beer money...LOL

You are really going through 70 gallons a day? Holy cow.

[DarkSide]

I have not used her enough to get a good sense of how much is really left in the tank. So when guage starts reading 0%, i get nervous. When i get low fuel warning, i call it a day. Last couple times had been 55~60 gallons.

Edited August 26, 2015 by DarkSide

[DarkSide]

That seams really bad, however when you factor in 24' boat, 5k ballast, 55 gallons in a full day puts me just under 9 gallons per hour of engine time. We are typically on the water for 9~10 hours. So even at 60 gallons, that's $180 to entertain 8+ people all day. That is cheap entertainment when you look at it that way.

[The Hulk]

Darkseid u are considering 15 x17 with a 1.25 trans? I was thinking 15 x17 is tkt with 1.48 trans assuming that's actually what i have need to check.

How did u design your custom sacs I'm thinking that's a better way as well there is a 2 inch rise in floor for the back foot of the lockers for where hose goes under so I thought about going custom to fit that shape.

Surf we can get 15ft back or so I agree it's slow but wifey likes it and I haven't had more than a few hrs to surf this year to play around much. The pocket feels good but I know it could be better

Edited August 26, 2015 by The Hulk

[The Hulk]

Hey at least your marina sells 93 oct! Only 91 here so must use 5gal cans but I found a huge jiggler syphon on Northern Tool that will empty a five gallon can in 25 seconds it's the world's est invention! Its faster than at the pump!

Edited August 26, 2015 by The Hulk

[DarkSide]

Hulk,

Only 91 available in AZ. Fortunately the Marina at the lake we go to on weekends sells 91. I have done the gas can route before, I just use a piece of 1 1/4 hose, and it works just like the jiggler. Just a few seconds to drain a 5 gallon can.

For custom sacs, just make measurements and create a drawing. Then send the drawing to Wakemakers or Barefoot international (fly high). Over the summer Wakemakers was running 6+ weeks, Barefoot turned them around in 2 weeks, right before 4th of July. Wakemakers is a little cheaper, and now that we are getting closer to end of season (for most of the country), their turn around times may be faster. You will also need to reinforce your engine wall dividers, there is a thread on that as well. I am attaching the drawing of my bags so you can see what they are looking for. They are awesome, fills up all the space up under my rear corner seats all the way back to the transom, NO Wasted space!

~Joe

[The Hulk]

Wow I was not imagining they could make them that complex that's why I was hesitating on the custom ones they even did the curve pretty well? Then they just reversed pattwrn for other side correct ?

[DarkSide]

They did square stuff off, but still works fantastic. The "extra" bag just ensures it makes it into every inch of space. The extra is also such a small amount that bag confounds perfectly, without strange folds or pockets.

[The Hulk]

Like 1" extra or 1/2" bigger all around?

[The Hulk]

Darkseid u are considering 15 x17 with a 1.25 trans? I was thinking 15 x17 is tkt with 1.48 trans assuming that's actually what i have need to check.

[DarkSide]

Only extra is from squaring the bag, so just a touch extra in the back corner.

1.48:1 on the tranny.

[catalac]

LOL, that isn't really the issue, the issue is i run out of gas. I have had my low fuel warning the last two outings. So gaining even a little efficiency would get me through the day. I just need 10% efficiency gain! Malibu made the tank 8 gallons smaller from '14 to '15.

It sucks deciding whether to go home or go to the marina. Not having to cut the last hour of the day because i am out of gas would be AWESOME!

And $20 is beer money...LOL

Same issue with 22vlx, tank is only 46 or 48 gallons can't remember and seems useful volume is 38-40 based on gauge. Drove me nut this summer had to do 2 fills a day if going hard.

[nyryan2001]

Man buys $125k 24' boat with triple axle trailer towed to lake with 1 ton dually, worries about saving $20 per trip.

What kind of garbage post is this?

[DarkSide]

What kind of garbage post is this?

Post could read a couple ways, i do not believe it was intended maliciously, but more of a serious irony humor perspective. If you read it assuming positive intent, it is actually funny.

I see the other side as well, but did not take it that way.

[The Hulk]

Say 3000rpm loaded up with a 14.5x14.25 @ 3000rpm with a 1:1.48 trans = 2027rpm at prop × 14.25" pitch = 2407ft/min = 27.3mph thrust.

17 pitch = 32.6mph thrust

Working backwards that equates to about 500 rpm difference about 2500 rpms at engine for the 17" pitch to match the 27mph thrust of the 14.25" pitch (not accounting for diameter difference and assuming prop is not slipping...

NOTE that the shaft angles the prop downward in comparison to FWD motion, bow rise further increases the amount the prop is shooting downwards (angle X) in the attached pic. So technically the increase in mph thrust does NOT directly translate equally to FWD motion mph increase. Assuming engine is not being blogged down then when bow is up higher the FWD angle of the prop is worse and less translation to FWD increase than at idle or cursing speed when bow is DOWN and prop angle is better transferring energy to FWD motion etc..

assuming something in the 20-25 deg angle "prop angle" not boat angle at surf speeds: this curve which i cant seem to find info on should be exponential for every degree more in vertical angle should be exponentially LESS FWD energy. (if the angle was higher essentially your prop is trying to push the boat towards the sky and not FWD). But lets use a number such as 20-25 degrees would not equate to 25% less FWD movement/energy it should be much higher such as 50% or possibly higher. so at a minimum i would guesstimate something in the 50% range for effectiveness on calculations translating into FWD movement.

Roughly 5-6mph thrust gain would be huge...now how that translates with all variables such as haul angle and drag vs engine hp load, prop slip etc.. etc.. who knows but I'm assuming the engine will handle it (LSA) if it can then it would be about a 4 to 6 mile per hour increase at top end as well and whatever the inverse rpm reduction of the equivalent at surf speeds . Say all those factors cut calculated savings in half as i've stated above...then were still talking 200-300 rpm savings!!!!

My "GUESS" is as follows ?IF" the engine does not meet its match

14.5x14.25 VS the 15x17 : The 15x17 should lower surf RPMs by 300 (bigger diameter + bigger pitch) and net me a 4-5mph increase at WOT

Let me know if my Calculations are wacked or not.. haha

Edited August 27, 2015 by The Hulk

[The Hulk]

Protractor added to image for rough calcs/view

Edited August 27, 2015 by The Hulk

[Technicallyabu]

Who needs superchargers when you can have turbos. Link to Mercury 4.2 Diesel. Bolts up to the ZF63 drive. If I had money to burn Id repower with one just for the giggles. It'll spin a 17x17 no problem.

https://mercurymarine-gsdesign1.netdna-ssl.com/media/filer_public/4c/0c/4c0cf48e-c3d2-4493-bf9c-efb90f25972a/performance_curve_and_data_sheet_mercury_diesel_tdi_42l_370_tier3.pdf

[DarkSide]

I think your math is ok, however i think prop angle closer to 20 than 25...i agree 300~400 rpm drop