Big single or smaller twins for a 28-32 ft cruiser??

camaro_z28

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Sep 15, 2010
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I've been boat shopping lately looking for a 28-32 express or possibly flybridge. I'm stuck between a single 7.4 or twin 4.3's or maybe 5.0's. my main concerns are 1. fuel economy 2.performance and handling 3. initial price on a used boat and upkeep. Outdrives seem to perform better, but I know they are also more upkeep. I'm just looking for real life input on this delima. Thanks
 

erie_guy

Petty Officer 1st Class
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Jan 16, 2007
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269
Re: Big single or smaller twins for a 28-32 ft cruiser??

Camero,

My experience has always been with sterndrives. Yes they do take annual maintenance to have trouble free operation. On Lake Erie they should be fitted with magnesium anodes to keep corrosion in check. Every year the paint should be touched-up and the zebra muscles pressure blasted off the drive and bellows. Then change the oil in the drives every other year and the bellows every three years and you should be good to go.

The stern drives provide about 20 to 30% better fuel economy and have ~ 10 mph greater speed at cruise - compared to inboards. And they can operate in shallow water near the shore line and beaches without worrying about the props/shafts.

On a 28' boat, twins would provide better manuvering while docking although you would have more maintenance (x2) on the stern drives. For a 30', twin 4.3 or 5 liter engines would provide sufficent power. A 32' would be better propelled with 5.7 liter engines. When you get over 30' twins would be a necessity.

erie_guy
Port Clinton, OH
 

JoLin

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Aug 18, 2007
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5,146
Re: Big single or smaller twins for a 28-32 ft cruiser??

On a 28' boat, twins would provide better manuvering while docking although you would have more maintenance (x2) on the stern drives. For a 30', twin 4.3 or 5 liter engines would provide sufficent power. A 32' would be better propelled with 5.7 liter engines. When you get over 30' twins would be a necessity.

erie_guy
Port Clinton, OH

I think erie_guy has it right. I just finished struggling with the same question you have. Was looking for a 27-30'er. My first choice in the 27' 4Winns I just purchased, would have been a single big block. I couldn't find a good one locally in this size boat. As you get closer to 30' I think you'll find nearly everything is powered by twins, anyway.

In a flybridge boat of that class, you'll want twins. There's a lot of sail area, and a single engine will make low-speed maneuvers a real challenge in any kind of wind.

My .02
 

dsiekman

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Re: Big single or smaller twins for a 28-32 ft cruiser??

Twins...unless you are looking at a single diesel with a bow thruster and don't plan to go over about 20 knots (Albin TE or similar). I have twin injected 5.0's and this summer burned about 175 gallons over about 20 hours of engine time. That equates to roughly 8.75 gph. Now the disclaimers...I usually let the boat warm up for a few minutes before leaving. I have about a five minute run at idle out of the no wake and then into the spot where we usually anchor up. I did a couple trips in the evening - probably 2-3 hours total time - at idle.

The guy I bought the boat from said to expect about 12 gph at a 30 knot, 3200 rpm cruise. I can also tell you that at WFO she'll drain 25 gallons PDQ!
 

25thmustang

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Re: Big single or smaller twins for a 28-32 ft cruiser??

I think it depends on the boat. The Bayliners in that size range I see a lot with singles. More or less most other brands once your over 27-28' your looking at twins.

Twins will be better for docking and handeling, and offer the ability to limp home should one go (unless an issue that deals with both motors). Twins will cost more, probably more fuel, more maintenance, more of everything.

Personally, at this size range of boat, I would prefer the twins, but there is a 28' Rinker near my slip with a single big block, and I have heard (I believe on here) that it should be a 50 mph boat. Amazing if you ask me, as my twin 350 powered 29'er is a 35 mph boat!!
 

NSBCraig

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Re: Big single or smaller twins for a 28-32 ft cruiser??

If I had a choice I'd always go with twins.
 

haulnazz15

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Re: Big single or smaller twins for a 28-32 ft cruiser??

I think the breaking point is about 28' for me where I'd want twins. It's mainly the advantage in docking maneuverability that I'd want. I also agree that T-4.3L's are good for anything 30' and under, but going larger will probably necessitate the 5.7L's. Once you get above 34' or so, I say get the biggest engines available.

Assuming you don't have any major repairs, having twins is only going to be marginally more expensive than running a single screw. You'll have an extra oil change and maybe $100 in other misc items for the extra engine plus fuel cost. The advantage of twins is that is isn't necessarily double the fuel cost since the engines will be running lower rpms for the same speed.
 

dsiekman

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Re: Big single or smaller twins for a 28-32 ft cruiser??

Personally, at this size range of boat, I would prefer the twins, but there is a 28' Rinker near my slip with a single big block, and I have heard (I believe on here) that it should be a 50 mph boat. Amazing if you ask me, as my twin 350 powered 29'er is a 35 mph boat!!

A lot of that is hull design. My 29' cruises in the low 30's and tops out around 50 with twin 5.0's (250hp VP's). From what I understand, the 29' Tiaras (Would have been my first choice) with twin 350's cruise in the mid twenties and top out around mid 30's. There is also the difference of inboard vs. I/O.
 

26aftcab454

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Re: Big single or smaller twins for a 28-32 ft cruiser??

backing my 26ft Wellcraft with a single bravo III is really tuff - my slip neighbors always enjoy a windy day for entertainment.:eek:
and I have been doing it for a while.
 

JoLin

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Re: Big single or smaller twins for a 28-32 ft cruiser??

A lot of that is hull design. My 29' cruises in the low 30's and tops out around 50 with twin 5.0's (250hp VP's). From what I understand, the 29' Tiaras (Would have been my first choice) with twin 350's cruise in the mid twenties and top out around mid 30's. There is also the difference of inboard vs. I/O.

I agree. Depending on the type of boat the OP chooses, big blocks really aren't needed. Maybe for a tank like a big Bertram, but certainly not for an express cruiser in the 28-32' size class. One friend with a 1989, 30', 11' beam Searay, can top out in the high 40's with a pair of 5.7 Mercruisers.

Another with a 34' (might be 36') Silverton flybridge sedan, cruises at 18-19 mph with a pair of small-block Chryslers. That's a semi-displacement hull, but the motors are nearly 30 years old... so I don't think you could call them 'overstressed'.

My .02
 

25thmustang

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Re: Big single or smaller twins for a 28-32 ft cruiser??

It seems the I/O boats can run a lot more mph than the I/B boats. I know hull design and weight play large rolls as well.

I couldn't imagine my boat cruising at it's current top speed, and topping out in the high 40s-50 mph.

Also, a LOT of older vintage sedans had small blocks and ran well. Up into the 34' range, Silverton, Chris Craft, Trojan etc... were putting in 318s, 360s, 350s etc. These boats cruised 18-20 knots and topped out in the mid 20s. Not speed demons, but for 12K-14K lb boats (dry weight) thats not too bad!
 

dsiekman

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Re: Big single or smaller twins for a 28-32 ft cruiser??

backing my 26ft Wellcraft with a single bravo III is really tuff - my slip neighbors always enjoy a windy day for entertainment.:eek:
and I have been doing it for a while.

I feel your pain! I used to have a 25' cobalt with the 7.4/BIII. A friend with a 115 on the back of his 20' CC kept telling me to just "bump it in and out of gear". Yeah right. That engine/drive/boat combo was REALLY touchy and would jump sideways if you tried to "bump" it.

The twins make tight manuevering MUCH easier!
 

25thmustang

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Re: Big single or smaller twins for a 28-32 ft cruiser??

Check out the photo below. The boat on the far left is maybe 30-40' from the beach on shallow days, and is a single I/O. I have never seen him dock it, but I can imagine it's a chore!!!

Slip02.jpg
 

dockwrecker

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Re: Big single or smaller twins for a 28-32 ft cruiser??

Twins. I had a 26' Fiberform Baja flybridge with twin 350 mags that cruising 30mph ate about 11 gph for the PAIR. This was also a 9000 lb boat. So the milage isn't really that much worse with twins, they're not working as hard. And on a high profile boat like that one was, twins were a must for docking.
 

QC

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Re: Big single or smaller twins for a 28-32 ft cruiser??

I've piloted a 340 Bayliner Express Cruiser with twin 350 Mag Bravo 3s at 46 MPH. I/O vs. IB speed is more about trimmability, drag, and angle of attack than hull design . . .
 

dockwrecker

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Re: Big single or smaller twins for a 28-32 ft cruiser??

Ha. That flat butt bottomed Fiberform of mine would pull 54 mph! And that's quite a rush on a flybridge!
 

dsiekman

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Re: Big single or smaller twins for a 28-32 ft cruiser??

Check out the photo below. The boat on the far left is maybe 30-40' from the beach on shallow days, and is a single I/O. I have never seen him dock it, but I can imagine it's a chore!!!

Slip02.jpg

I would kill for that slip! I have a 9.5' beam in an 11' wide slip...with no finger piers. The only option is to back in.
 

ingalp01

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Sep 11, 2010
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Re: Big single or smaller twins for a 28-32 ft cruiser??

In my opinion, it's easier to control/pilot a large boat with twins than with a single I/O. especially when it comes time to navigate the harbor and dock it up...
 

JBF 1962

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Oct 29, 2010
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Re: Big single or smaller twins for a 28-32 ft cruiser??

In my opinion, it's easier to control/pilot a large boat with twins than with a single I/O. especially when it comes time to navigate the harbor and dock it up...

Kewl lookin Chris-Craft...you should post more pics! :D
 
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