www.iFourWinns.com

OK, I have the 6.0 Crusaders with V-Drives.
Specs show at 3500 RPM should be running 29MPH, and at 4000 RPM 33MPH.
Best I do with tides and wind in my favor is about 24MPH at 4000 RPM.
Seems to be 4000RPM is where she is most happy running.
3500 RPM seems sluggish, its on plane, but seems just barely.
Props are original, just retuned, and rebalanced, and are the originals, the 18x25's.
Also sent the gauges back to Faria, and they are all in perfect order.
RPM's tac out where around 5100-5200 RPM, right where Crusader says it should be.
I am bottom painted.
Seems the best speed comes with the trims tabs approximately 3/4 of the way down.

Other 348 owners, or owners with the same engines and hulls....
What is your speed at 3500 RPM?
What is your speed at 4000 RPM?
How far down do you keep your trim tabs?

Sure would be like to running 29 MPH at 3500 RPM...
I can see loosing up to 5 MPH if fully loaded down, but that would be 28 MPH at 4000 RPM, and I am only getting 24 MPH MAX at 4000 RPM when conditions are ideal. Most of the time it is more like 21-22 MPH at 4000RPM.

Would like to hear from other 348 owners with Crusader inboards please!

Can't help you with the Crusaders, but I can give you my experience with Volvo Pentas. I have a 2007 Vista 358 with twin VP 5.7 GXI's (320 HP). With original, non-reworked props, I run with tabs full up and drives full down or trimmed slightly up if perfect on the bay. I cruise at 32 mph at 3800 rpm. I can run as low as 25 mph at 3400 rpm, but struggle to keep on plane. Top end is about 44 mph at WOT (~5400 rpm). I installed fuel flow meters and picked 3600 - 3800 rpm as most economical cruise speed. Hope that helps!

Paul

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Transcendence II
2007 Vista 358

My speeds pretty much match Paul, it should we have the same engines and drives. V-drives should be slower. I've never got to 44mph, I top out at 42mph on my GPS.

Wait for Bill K. to respond he has the same engines and drives as you.

I used to run with full up trim tabs but any wakes or wave would send me all over the place. In any messy water try a few seconds of down trim tabs, a trick I learned from Bill on this forum.

If he doesn't answer search his posts, he may have already posted the answers during the great v-drive vs I/O debates.

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2008 V358 Two-tone Blue V/P Dual Prop 320 HP
Lake Winnipesaukee, NH

I have 2006 348 vista with VP 5.7Gxil inboards. Have had props computer tuned. Good botom paint, also have docked in river which is highly fresh water and we almost never have any bottom growth/barnacles.

I have the exact same performance as you (although i think in knots as opposed to mph).

At 4000 rpm we generally only get 20-22knots (24-26mph)
I generally cruise at 3800 and run at 19knots

Boat doesnt seem to come alive until passes the 3500rpm mark. Doesnt eve nthink of planing till it passes 3000rpm. And yes I am using my tabs correctly. Seems as if I could use more tab throw though, have wondered if they are not moving the length they should. Bow rides pretty high

generally have a pretty full load of gas/water/passengers and the admiral keps us pretty well stocked with food/clothes/etc. but i have not much different perf at 1/4 tank of gas. Wondered whether my rpm guage was correct, engines seem very quiet for 4000rpm, but i see you checked your guages as well.


Long story short I have the exact same experience as you and it has bothered me that something is making me run slow but for life of me cant figure it out. A little comforting to hear you are the same.

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2006 348 Vista
"Cruisin Home"
Hampton NH

Shark, yeah agree for 4000RPM seems quiet, thats why I sent my gauges in. But seems most happy still between 3800-4000 depending on wind and tide. Of course seems like wind is always against me and tide always against me, go figure right....

Anyway will would be nice to hear from someone with the Crusader setup, as they are supposed to be much higher HP than the Volvos Shark. But as we both said, we are pretty heavily weighted down too with water toys, beer, water, food, more beer....

Thanks for the replies guys with stern drives, but can't compare at all....really looking for replies from inboards, and hopefully those with Crusaders as well....

I can see a little difference if we are empty on water, and about 1/4 tanks gas, much very negligible...

Also curious if anyone has gotten fuel flow sensors hooked up to the crusaders to display on the C80, at least that way I could see @ what speed/RPM I am getting my best gas milage.... Any input on that? I will make another thread for this though....

Wow, my speed sucks! I bought a 2009 358 this year with Volvo Penta 5.7 v-drives. Getting used to the slower speed of this bigger boat has been my biggest problem as my old boat did 53 mph.
My top speed is only about 33 mph at 5200 RPM. So I cruise at 4500-4800 rpm, about 29 mph. I don't know if my props are stock.

Wow you cruise your 358 with RPM's sitting between 4500-4800?

I would think that would be pretty hard on those engines with sustained cruising RPM's that high.

Mike.

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Current Boat
- 2001 Four Winns 328 Vista "Hour Decision"
- 2010 310 Mercury Inflatable

Previous Boats
- 30' Doral Prestancia
- 25' Doral Citation

It sounds like his tachs and speedometer are way off. Too high RPM, too slow of speed for revving that much. Unless he has 6" shag carpet attached to the bottom of his hull, and fishing line wrapped around both shafts.

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One of 4 Previous (Sold) Boats:
2000 Four Winns 268 Vista

Current Boat: 2004 Chaparral 235 ssi cuddy

For most motors....optimal cruise RPM is 75% of Wide Open Throttle...

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2007 358 T-5.7GXi IB
Previous Boats
'08 H240, '08 V318, '04 268, '04 225

How would one know if their tach was off? It would be surprising if both were off because the MPH is through the GPS.

I have previously asked our marina tech to drop over to our boat and request he put a digital timing light on our engines to verify how close our tachs are to his digital timing light. His timing light is capable of reading engine RPM's. It's a pretty quick check to do......

Mike.

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Current Boat
- 2001 Four Winns 328 Vista "Hour Decision"
- 2010 310 Mercury Inflatable

Previous Boats
- 30' Doral Prestancia
- 25' Doral Citation

I searched through the old threads and found this link to a test of the speed, rpms for the 358 with crusaders.

The 348 and the 358 are the same boat.

http://www.boattest.com/oem/test-result ... rom_gi=yes

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2008 V358 Two-tone Blue V/P Dual Prop 320 HP
Lake Winnipesaukee, NH

ACME props that explains some of it.

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One of 4 Previous (Sold) Boats:
2000 Four Winns 268 Vista

Current Boat: 2004 Chaparral 235 ssi cuddy