Single engine / twin comparisons revisit ... :)

[Hai Nhi]

Good evening everyone.

I know this has been discussed a couple of times here. Just to ... refresh everyone's memory, on more details:

+ More gas on twin, but how much more (in term of percentage)?
+ Heavier on twin: if strickly on a 27 footer (Sundancer / Regal for example), would it be that bad (tail drag vs getting on plan much quicker)?
+ Maintenance - more on twin: again, small maintenance (oil change, etc...) is probably "ok". What about major ones (100 hrs, etc...), would it break one's wallet/budget? I know if you have to change both engines then you're pretty much doomed I guess. Hehehe.
+ On the plus side, twin has a backup, single doesn't! What else? More power maybe?
+ Anything else I miss, please advice.

For my first boat, I'd definitely go with single. But just for future references, if you don't mind answering.

Good weekends everyone.

Nhi

 

[jestor68]

Re: Single engine / twin comparisons revisit ...

You pretty much got it. Except for being more maneuverable around the dock, they are pretty much double trouble.

 

[tpenfield]

Re: Single engine / twin comparisons revisit ...

27-28 feet seems to be the break-point between single and twins.

I'm just starting down the path with twins, having owned a single for 8 years . . . The maintenance is 'fun', because once you do something to one engine, you are only 1/2 done.

We shall see about the fuel consumption . . . . but according to BoatTest.com, I should be seeing about 1.5 mpg at cruise (twin, 33 footer). My previous boat ( single, 24 footer) was about 2.2 mpg. So, that is pretty good with twins.

I think a 27 footer with twins is too much weight in the back . . . take a look at an older Formula 272 . . . versus a 292 or 311. The 272 (27 feet) looks like it is sinking compared to the bigger boats. The 272 sure goes fast enough, but sitting funny in the water would bug the poop out of me.

A buddy of mine has a SeaRay 270 with single 7.4 carbed . . . he tells me it takes a lot of the engine to bring it up on plane. Once up, he can back it down a bit. He is worried that too much 'flooring' the thing to get it on plane could eventually lead to some pre-mature engine issues. So, there is something to be said about power matching to the boat.

So, as you look at prospective boats, it is something to consider as you look in that 27-28 foot range boats with single engines. you gotta ask yourself, should this boat really have twins?

 

[JoLin]

Re: Single engine / twin comparisons revisit ...

Pretty much what tpenfield said above. When I started shopping for my current boat, preference was a single big block. I don't run offshore and wanted to avoid the maintenance expense of twins. I couldn't find a decent boat with a single engine.

The one boat I tested with a 7.4 was a 1993 28' Carver express. It moved out okay, but when I looked at the specs I found that boat to be roughly 1000 lbs. lighter than comparable boats of that size (Searay, Larson, and my Four Winns). You need to actually try out whatever boats you're interested in. There are times I wish I had a pair of V-8's rather than my 6's, so it's hard for me to imagine a single engine that wouldn't 'bog down' with a big load of passengers. I'm also talking about boats from the 1990's. Boats made in the last 10 years are putting out a heckuvalot more power than those did. Single engines and dual-prop drives are more common in under-30-footers now.

For guesstimating purposes, fuel consumption with twins will be roughly 50% higher than with a big single. Maintenance, of course is twice as expensive. If you do your own wrenching, you'll find twins to be a tight fit. There are things I'm tempted to do myself, that I wouldn't try without having another person with me to haul me out if I get stuck.

What twins offer is easier low speed handling than a single (inboards are even better than I/O's in that respect). That factor is big for me- most of my boating is done in very breezy conditions. Deploying an anchor, then backing down on a raftup is much easier with twins. That's an activity I do all summer long. Then there's the peace of mind of twins if you run offshore or in lousy conditions.

As for being 'butt heavy' mine really isn't, but again I'm running V-6's instead of V-8's. I run level on plane and easily manage bow attitude with the outdrive trim. I only need my Bennetts to control list.

My .02

 

[dingbat]

Re: Single engine / twin comparisons revisit ...

For guesstimating purposes, fuel consumption with twins will be roughly 50% higher than with a big single.

This assumption is incorrect. HP is HP. It takes X amount of HP to move a boat at X speed and it takes X amount of fuel to generate that HP. Of course, the twins will introduce a loss of efficiency thru weigh and drag, but nowhere close to the 50% figure mentioned. I would put the figure closer to 10-15%

As for maneuverability, "easier? translates into less skill required. An experienced boater running a single will run circles around a weekend warrior with twins and a bow thruster.

 

[JoLin]

Re: Single engine / twin comparisons revisit ...

This assumption is incorrect. HP is HP. It takes X amount of HP to move a boat at X speed and it takes X amount of fuel to generate that HP. Of course, the twins will introduce a loss of efficiency thru weigh and drag, but nowhere close to the 50% figure mentioned. I would put the figure closer to 10-15%

As for maneuverability, "easier? translates into less skill required. An experienced boater running a single will run circles around a weekend warrior with twins and a bow thruster.

You are correct about fuel consumption. My error.

As for the maneuverability observation, it wasn't about an experienced boater versus a weekend warrior, it was about ease of handling- singles vs twins. I've run a 21' single outboard, a 24' single I/O and my 27' twin I/O. Got pretty good with all of them. Twins are easier to maneuver at low speed, hands down, particularly when backing in breezy conditions. And no, none of mine has/had a bow thruster.

 

[JB]

Re: Single engine / twin comparisons revisit ...

There is a third option you haven't covered: Main engine (outboard) plus an auxiliary. It offers some advantages over both, but won't plane the boat when the main goes down.

 

[Hai Nhi]

Re: Single engine / twin comparisons revisit ...

Well,

I'm looking at one of the 270, '99. It has a 502 Mag MPI (420 HP). Now that's big, right? Is it too big, or is it good to have extra power? This one also has a bracket on the extended swim platform for a trolling motor. Not sure if a bigger auxiliary motor can be mounted. Asking $27.5k. Bumber thing is that it doesn't have a trailer! New one costs ~$7000 (galvanized). No genny either (not that I need one but just comparing with other option: which is a '98 with steel trailer, genny, 7.4L asking $29k). Usually 10% lower than asking price is a highly norm around here, I think.

Man, there's this one Regal, 2000 2760. Looks so nice, but has twin (hence the thread). Practically brand new looking. The twin are 4.3 GI, 180HP each. Asking $32.5k, no trailler. So pretty out of my range, period! hahaha.

Nhi

 

[JoLin]

Re: Single engine / twin comparisons revisit ...

Well,

I'm looking at one of the 270, '99. It has a 502 Mag MPI (420 HP). Now that's big, right? Is it too big, or is it good to have extra power? This one also has a bracket on the extended swim platform for a trolling motor. Not sure if a bigger auxiliary motor can be mounted. Asking $27.5k. Bumber thing is that it doesn't have a trailer! New one costs ~$7000 (galvanized). No tranny either (not that I need one but just comparing with other option: which is a '98 with steel trailer, tranny, 7.4L asking $29k). Usually 10% lower than asking price is a highly norm around here, I think.
Nhi

My 2 V-6's put out a combined total of 410 horsepower and I have the weight and drag of 2 engines and 2 outdrives. I stated above that I sometimes wish I had V-8's instead of V-6's. So, no, the 502 Mag is NOT too big. As long as you don't need twins for their safety aspect, I'd say that sounds like a real nice package. It'll run rings around the boat with the 7.4, too.

What do you mean about it not having a 'tranny'. I think you meant 'genny' (generator)?. They're nice to have, but I don't and we make do. Depends on how long you plan to spend away from the dock and how well you manage your power consumption. Right now I have only one house battery, but I can get 2 days and a night out of it.

I pre-cool the fridge and shut it off at anchor, use a good cooler rather than the fridge for perishables, and I replaced all the cabin lighting with LED's. I have a bunch of '3 for $10.' LED flashlights hanging on hooks in places, and 2 small LED lanterns that I hang from the bimini frame to light the cockpit at night. I call that my 'redneck custom cockpit lighting'. There's no TV and we use a portable stereo rather than the one in the boat. I only turn on the fresh water pump when we need to run water. I have a manual head, so no power consumption there. In the morning I run the port engine for 45 minutes or so to heat water, so the battery gets a 'bump' from that.

Keep in mind your cooking needs. My boat has a 2-burner alky/electric cooktop in the galley. I keep a collapsible single-burner propane stove aboard all the time. I use that to make my morning coffee in the cockpit rather than waking Linda. I sometimes bring my 2-burner propane camp stove that we use in the cockpit when possible. I prefer that to cooking with alcohol below deck, but the alky stove does work fine.

If I were staying out for longer periods at a time I'd need to either add more stored capacity (batteries) or add a generator. I've planned for a long time to add a second house battery- just haven't gotten around to it.

 

[Hai Nhi]

Re: Single engine / twin comparisons revisit ...

Thanks a million John. That is exactly a type of answer that I love most: details descriptions of what people do when out on the boat. . And yeah, it was a typo for genny.

I've just talked to my wife last night, showing her differrent **** pit seat configurations. And both of us agree that a combo of double helm seat AND a L-shaped front port side bench (just like in a 1999 regal 2760 for example) is our favorite. But all the 2760 listed for sale near me have twins

So I guess for now, my priority search would change a bit. Regal 2760 single engine would come first (used to be sundancer 270). If any one knows if a good brand & year (newer prefered) in the price range of $20-$30, please let me know.


Seems like regal 2760's don't come w single that often, if they do at all.

Man, time adjusted already. I loose 1 hr of the needed sleep. Hahaha, stayed up tooooo late last night working .... on boat search

Nhi

 

[JoLin]

Re: Single engine / twin comparisons revisit ...

One thing I have found with larger boats with a single engine, owners really "beat" on the engine to get any sort of performance from it.

I wonder if that's more the case with the 'old' motors, like the 7.4? If I remember correctly, that puts out something like 330 hp vs. the Mag 502 he was looking at with 420 hp. Agree that Hai Nhi really needs to try a single before buying, tho.

 

[Hai Nhi]

Re: Single engine / twin comparisons revisit ...

Hi John,

I'll be checking out the Regal 2760 tomorrow, which has twin 4.3 Gi just like yours. You said sometimes you wished yours be a V8. In what scenario would that be? The Regal dry weight is 7800, which is about 300 heavier than your Four Winns (by the book). I wouldn't be racing or anything, but having an option to run fast would come in handy, I guess?!

Also, I'm not really sure how different is the HP rating between a single vs a twin setup. Would a 360 HP twin the same as single 360 if all else equals? Should be right? If so, Bubba, when you said single engine on big boat has to get "beaten" to get any performance, wouldn't it be the same on a twin too, if they're rated the same HP? HP ratings are max an engine can do, right? Newbie questions for sure.

I would also try to get a sea trial on the Sundancer 270 with that 415HP (8.1L) to try out. Seller claims it can run up to 45mph (vs only 30mph on the Regal 2760).

So in short:
- I really like the Regal layout (double helm seat PLUS L-shape port bench, extra dinette with nice queen bed). It's just huge (9' 11"), heavy, and small twins (save gas on the plus side). About $3k-$4k more than the 270.
- For 270, I like the engine HP for sure (for gas consumption, not sure how it's compared to a twin 4.3 Gi). It's the biggest I in a 270 for sale I've seen so far. I'm okay with the cockpit layout but not so thrilled. Like cabin layout though, similar setup as a 2760 with that extra dinette.

If I get either one, I'd be trailering it. Probably not the easiest boat to launch, but I was wondering if it's super hard compared to say a 240 or not. Do I need a bow thruster on a twin? I was thinking of getting one if I get the single engine.

Thanks again.

Nhi

 

[JoLin]

Re: Single engine / twin comparisons revisit ...

I wish I had V-8's when I carry more than 4 adult passengers and a full load of fuel and fresh water. Bear in mind that I'm usually running through 1-2 feet of chop. Taking waves 'in the teeth' slows the boat. I have limited torque to overcome that, which means I can be thrown off plane unless I keep the revs up. THAT can mean a rough, wet ride for the passengers on a crappy day. The lake boating you'll be doing is different. If it's really the same setup as mine (205 hp injected engines), I'd try it out. Regal makes a nice boat. 30 mph top speed? Doesn't sound right. I've hit 36 (gps) with a full load, less than pristine props and crappy old bottom paint on the hull. Maybe the seller doesn't have a GPS and is quoting 'speedometer'. FYI, a portable car GPS will tell you how fast the boat is going. Take one along if you can.

The Dancer should run pretty well with 415 hp, but I'm a bit critical of the claimed top speed. Not impossible, but I'd guess high 30's to 40 mph.

Performance- twin 180's vs single 360. The twins should perform a bit worse due to the weight penalty of a second complete drivetrain, and the added drag of a second lower unit and prop.

My .02

 

[Hai Nhi]

Re: Single engine / twin comparisons revisit ...

They listed at Volvo 4.3 Gi 180 Hp each, no info on the outdrive. I'll find out soon enough. But would single vs dual prop matter much in a twin set up?

And, how would the 4.3 Gi's be differrent in HP???

I would be doing mostly lakes and delta, but I would assume 20-30% around the bay too because I'm only 15-30 minutes away from local San Francisco Bay marinas. Some Local boaters here say in early morning it's not that choppy.

So if I lean toward power/performance, the 415Hp 270 would beat the twin for sure it seems.

Quality and resale aspect: would these two be pretty comparable?

Nhi

Nhi

 

[QC]

Re: Single engine / twin comparisons revisit ...

If all else is equal the single power plant will be faster and have better hole shot. This is sort of your horsepower question.

If all else is equal dual prop drives will have better hole shot. Single or twins.

If all else is equal twins will have better resale value, same with dual prop drives.

And finally, if all else is equal, single prop drives, twins or single, will usually be a little faster top speed. Not a significant factor for your application as the difference is generally above 60 MPH. I would ignore this.

 

[JoLin]

Re: Single engine / twin comparisons revisit ...

They listed at Volvo 4.3 Gi 180 Hp each, no info on the outdrive. I'll find out soon enough. But would single vs dual prop matter much in a twin set up?

And, how would the 4.3 Gi's be differrent in HP???

Nhi

They wouldn't. They're either 180-190 hp carbureted motors (designated 'GL', I think) or 205-210 hp injected. That's what the 'i' in Gi designates, so something is wrong in the seller's description.

Dual props probably wouldn't make a big difference in this application. Nice to have, but there's a tradeoff- the OEM props on a duo-prop drive are stainless and cost MUCHO bucks to replace if you hurt 'em. I wouldn't let the fact of single vs duo-props drives influence me much. They're both Volvo 'SX' series drives and they're very good when maintained.

 

[JoLin]

Re: Single engine / twin comparisons revisit ...

So if I lean toward power/performance, the 415Hp 270 would beat the twin for sure it seems.

Nhi

Nhi, you're really splitting hairs here. The 415 single isn't going to 'blow the doors off' the twin. They're close all around, with the single engine boat potentially having a VERY SMALL performance advantage (speed and fuel consumption) over the twin engine boat. That advantage can be completely nullified by adding a passenger or some extra fuel.

Does it really matter to you if one boat is 2 mph faster than the other at the top end, or gets on plane 0.5 seconds sooner, or uses 15 gph of gasoline at cruise vs. 16.5 gph?

Decide if, for safety and maintenance reasons, you have a preference for one engine vs two, and make your decision on that basis. The rest of it doesn't matter.

(I wrote at the beginning of these discussions that when I started shopping I wanted a single engine boat. The boat I liked best didn't come that way. I bought it anyway. I don't regret it.)

 

[Hai Nhi]

Re: Single engine / twin comparisons revisit ...

Well explained John. . I do appreciate all the inputs.

I checked out the boat. Looks really nice. The cockpit layout does confirm to be my favorite layout, with the combo of a swivel dual helm seat, and L-shape port side bench. Cabin dinette table is a bit cramp though. Not bad neither. But the v berth is not convertible, which limit the total dining seatings to 5 (6th seat is next to the bed, no table for her). My opinion is the layout looks nice/luxurious, but not as versatile/functional as that of the 1999 sundancer 270.

So for those who have 4 adults & 2 kids (under 10-12), how you find yourself in these layout (similar to that of 2000 regal 2760 and sundancer 270) at meal time?

Confirmed the engines to be Volvo 4.3 Gi, 205HP each. Single props, new in 2011.

So again, minor gas consumption is not a problem. I'd just like to know what I'm getting into. I like Everyone else have a budget for everything, including for hobbies like boating. Fuel consumption and maintenance cost would fall into the consideration when one decides what the max they can go, along with other cost factors. Or else, everyone would just do WOT all the time, tow skii/wake board all day, spend all savings on the biggest boat and what not . Maybe some of us can do that, but I'm not sure the majority can.


Nhi

 

[JoLin]

Re: Single engine / twin comparisons revisit ...

Well explained John. . I do appreciate all the inputs.

I checked out the boat. Looks really nice. The cockpit layout does confirm to be my favorite layout, with the combo of a swivel dual helm seat, and L-shape port side bench. Cabin dinette table is a bit cramp though. Not bad neither. But the v berth is not convertible, which limit the total dining seatings to 5 (6th seat is next to the bed, no table for her). My opinion is the layout looks nice/luxurious, but not as versatile/functional as that of the 1999 sundancer 270.

So for those who have 4 adults & 2 kids (under 10-12), how you find yourself in these layout (similar to that of 2000 regal 2760 and sundancer 270) at meal time?

Our dinette will seat 4, but it's tight. We might eat an occasional meal there, but we almost always eat our meals in the cockpit. We prepare food in the galley, fill our plates on the dinette table and carry them topside. Meals are more pleasant and fun outside the cabin. Nice scenery

Camper canvas turns our entire cockpit into a big tent that's as open or closed as we want it to be. That's where we are unless we're sleeping, cooking, bathing or using the head. I didn't take the boat out for the weekend so we could stay indoors. Remember, too, that any 'messes' in the cockpit are a helluva lot easier to clean up than a plate of spaghetti spilled inside the cabin. Six people eating a meal??? Not in my cabin.

No one boat, or type of boat, does everything well. If you want an 'apartment' with a lot of indoor space and amenities, an express cruiser isn't a good choice. If you like the idea of 'camping out', with a private enclosed area for sleeping and taking care of personal needs, an express cruiser will give you all the basics, and a big lounging cockpit for those day trips.

 

[Hai Nhi]

Re: Single engine / twin comparisons revisit ...

Agree!

I made an offer on it. I also got an offer for the trailer accepted. It's a triple axle aluminum from NEXTrail in great shape.

I'm picking up the trailer tomorrow if the seller keeps his promised schedule.

I should also know the decision on my boat offer tomorrow too. This seller had a felt-through transaction last August. So the broker still has a full survey dated 9/2012 ordered by that last buyer. Should I use that survey if they accept my offer (for probably 1/2 off) or go through my own surveyors again (which costs close to $800-$1k). Seller only owns for 2 years, puts in about 40 hrs, have a baby ==> hence the sale.

Nhi