To Twin or not to Twin

[PAYDAY]

I just bought a 91 2520 MV open back with no motors, factory bracket and was previously equipped with twins. (No Gauges or cables either) I am considering twin 225 Merc/Yammi 4 strokes. I would be grateful for any input from the group. This boat is bare bones now and I have a clean slate to work with. If you were doing this project how would you do it?
Thanks and I'll brace myself....

 

[gw204]

If I'm not mistaken, that hull is only rated for someting like 330 HP. So, twin 225s will probably make it extrememly difficult to get insurance for....not to mention it will be way @$$ heavy.

My Sailfish is rated for 400 HP and I've got 450 on it. I contact my insurance co. before I bought the boat and they OK'ed it. I talked to them again a few days ago as I was contemplating putting 250s on it. They said that I would run a good chance of having my coverage denied when I applied after the repower, so I chose to let it go.

General concensus is that hull does fine even with a single strong 225. If you want twins, I would probably go with twin 140s or 150s.

 

[John_Madison CT]

That would be way too much horsepower for that hull.

 

[B-Faithful]

Yammie v6 4 strokes are wide and probably wouldnt fit anyhow. Get a pair of 150's..

 

[Megabyte]

The 2520 MVSC is a 14 degree deadrise hull and is rated for 335 hp.
If you must have twins, go for a pair of 150 Yamahas. They really are great motors.

If it were me, I'd consider a single F250 as that seems to be the most efficient powerplant for that hull.

An F300 would be very cool, but I doubt seriously that the 300 would push the boat any better (or faster) than a single 250. The MVSC hull seems to have a 'terminal velocity' that hovers right around 35 kts and no amount of extra power will push that hull any faster than that.

Whatever you decide, post some project photos! :wink:

 

[DaleH]

Agreed, even if the hull could rate it, with a mod-V you will reach a limit of performance with THAT much horsepower. For fuel efficiency on a mod-V, Dunk opines that the 200 or 225hp is the best, but I would probably look at a 250hp if going new.

The thing that s#$ks about the Yummie F250 is that unless you burn high octane fuel, you're only running a ~235hp motor. But, that sure beats the F225 which is alleged to not even make the label rating of 225 horses.

 

[Wild Rover]

I have twin 200 Yammies on a 25 xld. Would prefer a big single to reduce operating and maintenance costs. Additionally, I think an F-250 or a Suzuki 300 will push that boat nicely.

 

[TopShot25]

I have a 2520 DVSC with twin Yamaha F150’s on the transom (no bracket).

First, I would like to state I love my twins and they have plenty of power. It all depends what you plan to do with your boat. Being it’s a MV I would guess your not really planning on trips out to Cortez. If you plan on mostly costal stuff, I would go with one engine and save a little gas and lots on maintenance. Vessel assist can make up for anything you may need. It will also help how your boat handles as you will have a lot less weight hanging off the back end.

That being said, my DV with twin F150’s cruises at 22–27 knots between 4000 to 4500 RPM”S. We top out at 43 knots.

 

[Outta Here]

The thing that s#$ks about the Yummie F250 is that unless you burn high octane fuel, you're only running a ~235hp motor. But, that sure beats the F225 which is alleged to not even make the label rating of 225 horses.

Does Yummie F-250 burn high octane or mid-grade? It may be worth the 10 cents or so/gallon for Yamaha Reliability. :wink: I know what you mean about F-225 down on HP. Mine barely planes off, maybe has 112HP :roll:

You're not still licking the bankruptcy wounds Yamaha inflicted on OMC, are you?

Back to the topic...I would love to have twin 150-4's...Yamaha that is.

 

[PAYDAY]

tHANKS FOR THE COMMENTS BUT IT LOOKS LIKE I'M TREADING WATER. I WANT REAL PERFORMANCE BUT DON'T KNOW WHAT TO EXPECT FROM THIS HULL. I SOLD MY DVSC W/ 454 I/O BRAVO 3 AND THOUGHT IT NEEDED MORE UMPHH. DON'T WANT TO OVER ENGINE THE GIRL BUT W/O ANY REAL TIME STATISTICS I AM GETTING INFO THAT IS BEST GUESS TYPE INFO. I KNOW MOST FOLKS ARE RIGHT ABOUT MAINTENACE AND FUEL ECONOMY PLUS START UP COSTS AND THAT PART IS ALL VERY TRUE. I JUST WANT TO THROTTLE UP AND GO, IF A SINGLE 250 WILL DO IT THEN GREAT! HOWEVER, IF IT LEAVES ONE WIHING FOR MORE THEN THAT'S WHAT I NEED TO KNOW.
I WAS A MEMBER OF THE OLD PILOTHOUSES BOARD AND THIS NEW BOARD IS CHOCK FULL OF GREAT FOLKS, I'M THRILLED TO HAVE YOU ALL AS BROTHER AND SISTER AFFECTIONADOS.
HERE IS A SHOT OF MY LAST 2520DVSC SHE IS NOW THE VESSEL ASST BOAT IN LOS ALIMITOS BAY.

 

[Outta Here]

A mod V will take a lot less power than your old Deep Vee to run the same.

For maxium zoom...how bout a Yamaha 350HP V-8.

 

[PAYDAY]

LOOKS LIKE IT'S GUNNA BE A YAM 250 LET THE PARTY BEGIN

 

[Megabyte]

Post some performance figures once you get her broken in a bit Jon. :wink:

Just to give you a comparison... My '96 2520 MVSC with a 225 OX66 has pushed my boat to 33 kts on flat water @ 5200 rpm, so you should be able to beat that figure with a new F250.

Good luck and congratulations!
Oh... and post some photos of that project when you get the chance! 8)

 

[PAYDAY]

Thanks Megabyte
I need a new canvas for my open back. Yours looks great. I assume you had it made at a local canvas shop, may I ask what it ran compared to factory and if you have any suggestions for improvements from original.
I am trying to wrap up the motor deal to-day, complete from prop to throttle. Will post as I go.

 

[Megabyte]

Jon, I never even priced factory canvas.
Mine was done by a local shop and is nearly identical to the original.
The material is Sunbrella, tho I don't recall the brand name of the window material. It is thicker than the OEM, if that matters.

Where mine differs from the OEM is in the mounting point at the top. The original used 'dots' (same items as on the sides) at the top, but that was replaced by a channel that captures a canvas 'bead' making it more weatherproof.

I roll my curtains up, but never take them completely off (though with this method you could), so this method of attachment works perfectly for me.

The only thing I would change would be to add a couple of snaps to the center section so that panel could be left partially open for ventilation in the summer.
Right now I just roll the canvas up and clip it with some lightweight aluminum caribiners (from Home Depot). This opening, combined with opening the port windshield about 1" allows me a little ventillation to keep the p-house from getting too hot in the summer while in her slip.

A couple of sets of well placed snaps would make this a lot cleaner and simpler.
Hope this helps!

 

[PAYDAY]

AWESOME KEVIN THANKS

 

[PAYDAY]

BUMMER.....250 was sold before I could wrap it up. Cancel the Party. Rethink applications.......twins......huummm