I'd go for the twins, even though the 496 is a great engine. You'll have much better maneuverability with twins on that thing. Good luck! :thumbsup:

 

Check the 280 thread for an abundance of information on this issue. I'd personally like some more info from you before I weighed-in on my opinion. lake or ocean? docking experience? maintenance costs an issue? top-end speed required? will it be in a marina (where more weight at the rear would make the boat more stable)? etc..

I've developed a strong preference for the Bravo over the Alpha. But I also have a preference for 2 engines given where/how we boat.

 

You have several replies to your question in the 280 DA thread.

.

 

I just took delivery on a 2006 280DA this June. When shopping for the boat, my mechanic indicated that because of the weight (8,500 lbs), twins would the better choice. He went on to say that 5.0 would be better suited than 4.3's. I have twin 5.0 Bravo III's. Note that the 4.3's should be fine. I say go with the twins.

 

The folks with the single 496 seem to like it and no one can predict the future! I'd say go with twins because it will probably have a better resale value. I'd see if you can get some fuel burn numbers for the two combinations, but I doubt there is much difference. I'd definitely upgrade to the 5.0's if that were an option. More hp available which means the motors won't work as hard and longevity should improve.

 

Either choice had its benefits. Its a toss up. I'd say on that boat a 496 makes most practical sense.

 

ok, now i'm starting to see that most all of you think that we should go for the twin engines (4.3 MPI A1)...but many have asked where we're boating...primarily icw and near-shore gulf and choppy salt bays/rivers...5.0 L / bravo is not available...got to choose from the twin engines or the 496 seacore br3 dts...the dealer that is 4 hours away may break the deal on the 496 magnum due to serious inconvenience (as one reader kindly reminded us!)...the twins are at marine max in our backdoor...any comments about their service and support? thanks.

 

I suggest you slow way down here.

Have you have put yourself in the position that it must be one or the other?

You are going in salt water.

Do these boats have fresh water cooling?

I love the 280 Sundancer but if I were in a salt water location I think I would opt for a used boat, 1 or 2 steps larger with V drives and fresh water cooling.

Salt water and outdrives can co-exist however you really need to keep on the maintenance.

 

Twins. I owned a 280 with 4.3 twins and its a sweet setup. Plenty of power but fuel tank is samll for that boat (100 gallons). I know of somebody with a single and he can't give it away. Just my 2 cents

 

Are you planning on trailering, rack storing, or leaving it in the water all the time?

 

Why does this topic come up so often I ask myself rhetorically? Having owned a single 280DA and ridden in all three variations of power plants and having friends that to this day own all, I have some authority to speak. Though it is true that I still like the single best in a 280, if I am to be honest, I still have to ask myself why? The “why” can always be answered in the “how” and the HOW is all about the usage pattern of the owner. For me it was simple, inland lakes and rivers.

With you being in the Gulf it seems at first glance a twin might be the better choice, but wait, this is not 1976 any longer and the advancement of marine power plants have progressed so far that the concern over risk (engine and/or drive failure) is greatly diminished. For those of you who say a single is less safe (or has greater risk) than a twin may be right, or you may be wrong, nobody knows for sure. Unfortunately there are no authoritative statistics I know of that could prove one configuration over the other like in general aviation (the old argument that a twin engine airplane is safer than a single – statistically incorrect by the way – not trying to carry a comparison between the two here so beg your pardon).

So if the risk concern is put aside, then what else is there given the performance numbers are about the same? Well, yes it is true as many have pointed out that close quarters maneuverability is tougher with a single (I can attest to that), but that alone certainly can’t justify twins can it? Then you have the challenges with corrosion in salt water both for the underwater gear and the engine. In this case the single is arguably better with the closed cooling and single drive. What about pure economics then, should that have a high weighted value because we know that one engine should cost less than two, right? And how about resale value, is the single really of less value than the twins (maybe, that could be proven, but in my market, singles sell for just as much as twins on the used market). I think the evidence suggests that on average, a single 280DA is just as good of a choice in general than its twin counterpart.

People are passionate about what they believe and I don’t expect anyone will change their mind but the question and the many answers does prove, yet again, these things always come down to personal preference and informed choices.

Good luck Mr. “On bizniz” with your new boat, I promise you are going to LOVE it!

Marq

 

Why does this topic come up so often I ask myself rhetorically? Having owned a single 280DA and ridden in all three variations of power plants and having friends that to this day own all, I have some authority to speak. Though it is true that I still like the single best in a 280, if I am to be honest, I still have to ask myself why? The “why” can always be answered in the “how” and the HOW is all about the usage pattern of the owner. For me it was simple, inland lakes and rivers.

Marq, I agree with most of what you said. The exception is the safety margin of two engines. Wait until the IAC goes wacky on the single engine and explaining to your wife, daughter, guests, etc. that there is a change in plans while waiting for a tow. I lost an engine last summer due to the IAC demon and it sure felt great to get her home safely and without too much fuss. The engines are MUCH better than 1976 but they do have issues: sometimes I think we have swapped mechanical problems (carb jets clogged) for electronic ones (dirty relay on IAC valve).

 

sounds like twins win....and off we go!

by the way, it's mrs. not mr. :smt038

thank all of you for helping with your 2 cents...this website is going to be a great help...we're upgrading from a 2001 Sea Pro Fish and Ski purchased new in 2002....boy do we have a learning curve ahead! :smt101

 

I've owned my 02' 280 from day one. I have twin 4.3 MPI with alpha drives. After 7+ yrs with my boat and over 900 hrs you need to be close to a good dealer like Marine Max which I really like. Once in their system your info can be pulled up from any other marine max location. very helpful when traveling. You will need to service the engines, outdrives, and misc trim items that always seem to break or need adjusting. Expect to get the gas tank cleaned at some point b/c of the ethanol in the fuel. Once every 5 yrs. You can do a lot of maintence on your own but there a few electronic sensors that will require a computor to reset and diagnos. I take very good care of my boat but it always goes in one a year for something. One regret is that I wish I had gone larger with a boat with inboard drives. docking the 280 with IO's is always a difficult especially on the intercoastal with currents

 

The good news is that no matter which configuration you choose... you'll be happy with it.
I wonder if there's any twin 6.2 / B3's around? That would be fun...

 

My 2008 has the Seacore 496 with DTS. There are several dual powerplant 280's and several more single 280's at my marina on the Ohio River.

After pulling my boat out this winter after 100 running hours in a trash filled river (folks say it was the worst conditions in 10 years), there no damages to the running gear and prop. I believe this is because the V hull pushes flotsam away from the running gear. This was common on the single 280's.

The dual 280's are entirely different. All of their running gear was damaged. One pier mate of mine had the outdrive ripped off his twin. I believe this is because the V hull pushes flotsam INTO the running gear.

So - all in all - I believe the single is lower cost and overall -more reliable when one consideres unexpected damage.

Thanks

 

my 2008 has the seacore 496 with dts. There are several dual powerplant 280's and several more single 280's at my marina on the ohio river.

After pulling my boat out this winter after 100 running hours in a trash filled river (folks say it was the worst conditions in 10 years), there no damages to the running gear and prop. I believe this is because the v hull pushes flotsam away from the running gear. This was common on the single 280's.

The dual 280's are entirely different. All of their running gear was damaged. One pier mate of mine had the outdrive ripped off his twin. I believe this is because the v hull pushes flotsam into the running gear.

So - all in all - i believe the single is lower cost and overall -more reliable when one consideres unexpected damage.

Thanks

lmfao!

Lower cost? Sure. More reliable? Whiskey tango foxtrot?

Using your logic, a skydiver would be safer if they only pack one chute so they don’t accidently pull the wrong cord.

Note to self: Do not take advice from chiefscientist.

 

I had one episode in pretty rough water where some discarded line from an old lobster pot got wrapped around the prop on my single engine boat. I was only about 50 yards off of a very rocky coast where the waves were crashing. It was in one of the deepest parts of Narragansset Bay off of Jamestown so dropping the anchor might not have done the trick in time. Luckily I was able to very quickly wave down a guy in a center console who towed me to safety. That fall I moved up to my current boat with twin 4.3's and I am more comfortable and the admiral is much calmer in rough water. Hey, stuff can happen on any boat at any time but for me having twin engines in my boating environment is the prudent choice.

KV

 

ntation - I welcome scrutiny. No problem. Scrutiny and feedback is a gift.

For the benefit of the reader here, I did investigate insurance on twin v. single. Since I was making a new boat purchase and had the choice of numerous boats - that was one of the first areas of research. After I decided on the big single, another dealer offered me a twin for nearly identical money. I then did a one-to-one, boat to boat comparison, 5 year comparison. The insurance rates were higher in all respects for the dual engines verses single in all questioned operating conditions. Another form of insurance, the extended warranty, was significantly higher as well.

That said, the "50 miles off shore" question was not asked. But knowing the fuel consumption, fuel capacity, and seaworthy rating of a 280 Sundancer, I would imagine not many of us would go 50 miles offshore - twin or single.

I do admire twins for some better handling in the wind while maneuvering. Frankly, I’m looking at a bow thruster and/or a thrusters that run off the Kohler genset (yes 240V). I’m investigating them now and looking at marine rated thrusters and controllers in the U.K.

As long as the power needs are met, twins/singles are yet another individual choice as are the consequences of the decision.

But I stick by my statement I have observed more damage on twins vs. singles for the reason(s) stated. The increased damage adversely affects reliability.

The pity here is you feel insecure. For instance, you can't use your name. Your insecurity leads you to create stories about threats, NASA, rocket scientists, parachutes, as well negatively react to others that might otherwise apply rational principles to reliability/security/safety question. You post constantly for validation. You NEED twins, triples, or quads. And when they get damaged, I’m sure you will not even think about this chain. Good luck - and I do sincerely hope you and your boat stay safe.

 

Not getting into the who's a better scientist/expert argument as I am very far from either. (A know-it-all? - probably!)

It is obvious that having two engines increases a boat's "limp home ability" by enabling it to continue to be propelled thru the water at some level of performance after one of its engine's fails. However, having those two engines does not enable the boat to be properly operated and normally used until the second engine is put back into service. Therefore, each time you begin a boating session, you can't "rely" on both engines to start and operate normally any more or less than you can "rely" on a single engine to start and operate normally. How many folks would even leave the dock with one of their engine's out? So, neither boat is more inherently reliable than the other.

This idea of debris being either pushed into or out of the path of the drives by the center keel is very interesting. It seems like Brett has observed some real differentiation in the damage experiences between single engine and two engine vessels in his marina. Anyone else here observed this at their marinas?

 

This idea of debris being either pushed into or out of the path of the drives by the center keel is very interesting. It seems like Brett has observed some real differentiation in the damage experiences between single engine and two engine vessels in his marina. Anyone else here observed this at their marinas?

Speaking as someone with commercial marine engineering experience, Mr. Bonner's assertion would certainly be groundbreaking if it were true. In 30 years of reading SNAME papers and industry publications I can't recall anything that would support it. In any event, I think he misses sight of the obvious; two pieces of hardware below the water line equals twice the risk of hitting something.

Henry

 

Consider that the original poster hasn't logged in since 9/24/09 -- two days after posting the question. I will assume that answering his question is pointless.

As for the larger question -- Twins vs. Single: It's been said a thousand times -- it's personal preference.
.

 

Single engine trawlers - de-tuned versions of very power motors operating at the bottom end of their power band - very reliable, very efficient, don't push hard, don't plane, don't break. Today's cruisers - High power versions of normally reliable engines - turbo charged, cruise at 85% max RPM, going to great places at great speeds - not the same.

Airplanes - twins have twice the chance of engine failure (boats too).
How much power does the remaining engine have when a twin loses one? Just enough to get you to the scene of the accident.

Boats - Slow speed cruising, or work boats operating several days per week, or safe, lake boating, or maximum efficiency, get a single.
High speed cruising, off shore activities, treacherous waters - get two.

SciFi Guy - Too small of sample in a very unusual boating scenario - no relevance.

 

Airplanes - twins have twice the chance of engine failure (boats too).
How much power does the remaining engine have when a twin loses one? Just enough to get you to the scene of the accident.

I have a friend who pilots single engine small planes who says something similar.

To the question of single vs twin engine boats;

1) Owning a twin engined boat, I have NO DOUBT twins cost more. There is no multi-engine discount when getting maintenance done. If one oil change costs $190, then two will cost $380. I have no doubt insurance is higher (although I have no direct evidence); Twin Engine boats *tend* to have a higher insured value. . .and that raises the insurance cost.

2) A twin engined boat running on one engine doesn't run like a single engine boat. With one engine, my boat has real trouble getting on plane. I have taken the engine up to 3800 rpm and not succeeded. Didn't push harder, as I am not going to run my engines at 4000 RPM for 30 minutes if I can avoid it.

The few times I have come home on a single engine. . yes indeed, I came home at hull speed.

3) Twin engines are not 100% reliable. They share the same fuel system. You run out of gas. . both engines die. You foul your fuel tank, both engines die. You run your boat through a pile of sea-grass. . .both engine intakes get clogged. On smaller Sea Ray I/O's. .. there is only ONE power steering pump. If my starboard engine quits. . .the boat is manual steering only.

4) This is very true: With two engines, you are MORE LIKELY to have an equipment failure. And it is true: If ONE engine is down, you are not taking the boat for a spin. Been there, done that. Now, I don't believe the probability of a lost weekend is double, since many mechanical issues are maintenance related, and when an item fails on one engine, you think about what is happening on the other engine.

5) Here is why you have two engines: When one engine dies, you can get home without the tow of shame. More importantly, if an engine dies in a REALLY bad spot. . (which in my case was in the middle of the Barnegate Inlet, complete with rocks, shoals, wind and strong tide), you can simply putter away at hull speed, without the crew getting into a panic.

From my experience, the fact you can usually still get home after an engine failure, without the tow of shame, is well worth the many, real costs, of twin engines.


Note: Just because you have twin engines, doesn't mean you can ALWAYS get home on one engine. I still maintain a SeaTow membership.

 

Henry, John... For people like me trying to learn these are great posts. Thanks guys
for taking the time.

 

You can't correctly compare the reliabiltiy of the diesel power plants in a commercial trawler with Merc gas engines to reach the conclusion that one gas engine is a reliable as two. Even very well maintained gas engines will fail at a much higher rate than diesels. I mean fail to start when you need them not self destruct. Simply put go fast gas engines are not diesels and two of them make it more likely you get home under your own power than by a tow.

 

This is a response to a PM sent to me by Brett Bonner. I am posting it here because my original post was made in haste, and comes off with a tone of “because I said so”. I apologize for that, I should have explained my position better. What follows is an attempt to do so.

I have quoted the appropriate section from his PM. The balance of his PM contains information on his background and boating experience. Given the recent stupidity that ensued over the publication of personal private information here recently, I will leave to Brett to make public the balance of his message to me if he wishes to, but the contents have nothing to do with the technical aspect of the post.


Brett,

We can go round and round on the 'reliability' discussion and at the end of the day it is a combination of semantics and the specifics of a given situation that makes the difference. I will also point out that while the article you posted is the best argument I have heard yet for diesel in favor of gas, it does not make the case for single gas vs twin gas. Marine diesel engines are built like the old Timex watches that were advertised to “take a lickin and still keep on tickin”. It is an apples and oranges comparison.

In a similar vein of semantics and circumstances is the discussion of whether the twin engine boat has better handling than the single. If you learned (as my brother and I were taught to by our dad) to dock a 36' sailboat while under sail and without an engine, then listening to either side of that discussion can be very entertaining.

As to your point about the vee hull. Your statement suggests to me that you are viewing what is happening under the boat from an intuitive perspective. In your PM you write:

“But there is another factor here. A v hull pushes crap toward the outside precisely where the twins are located. As the water fills back in, flosam has further to go before it hits the engine. And the boat is already gone. It can't be just "double the chance" that the twins had damage and the singles had none.”

Here is the thing. What you are describing is the behavior of a true displacement hull. At planning speed, by definition and fact, the Sea Ray hull has overtaken its bow wave, and as a result, the water flow under the hull is in straight lines. This is further ensured by the use of strakes (the vee shaped ridges in the hull, and the chines, the flat almost horizontal part of the hull where it meets the waterline when stationary. Intended to make the hull stay in a straight line and to keep it from skidding sideways in either turns, cross winds/currents, these features accomplish this task by ensuring the water flow under the hull remains parallel with the keel line by keeping it from moving from the keel to the outer edges. This also increases the water pressure under the hull creating lift and decreases the boat’s time to plane.

At planning speeds the amount of water being physically displaced is quite small, and the attitude of the hull bottom has changed to where the back 2/3 is roughly level (parallel with the water surface). In this configuration, the leading edge of the bow no longer looks like a snowplow. And, it is no longer the deepest part of the vessel’s draft. So submerged objects that are on line with the keel line will not get pushed to the side, but down and into our expensive BIIIs!

J.D. Van Manen and P. Van Oossanen, in Volume II of Principles of Naval Architecture, Chapter V Resistance, write:

“In contrast the planning hull form is configured to develop positive dynamic pressures so that its draft decreases with increasing speed, enabling it to run higher and higher on the wave it is generating, thus avoiding the large drag resistances experienced by displacement hulls run at speed. To attain positive dynamic pressures the planning hull avoids convex curvature of both the buttocks and transverse sections. Whereas, in the displacement hull, all means are taken to reduce flow separation, in a planning boat the straight buttock lines are cut off cleanly by the transom stern so as to induce early flow separation. The transverse section is typically a deadrise section with sharp intersection of the bottom and sides to form a hard chine from which the flow will also separate.”

Thus at any speed, the planning hull is designed to separate the port and starboard streamlines, and prevent them from converging at the stern. Additionally, at any speed the hull form is building positive pressure under the hull. Quite simply. it becomes pretty darned hard for a deflected floating object to be ‘sucked’ back under the hull.

At very low speeds, while the hull is in displacement mode, what you describe possibly could happen with the bow deflecting a submerged object into the path of a twin. It is also possible at low speeds, that submerged objects struck by the bow would return to their original course along the keel. But, at such speeds the risk of damage is also much lower.


Henry

 

I know that this thread has taken some interesting turns but I would like to bring motors in a 280 question. I recently looked at a couple of 2001 280's with the 6.2 320 HP Mercruiser Engine. This was offered in late 2001 after the 7.4 was done away with. Its 10 more HP than the 7.4 and a couple hundred pounds lighter than 7.4 Being that looked at these boats while visiting the upper NY state area no water test was possible. I did get some info from one owner about performance:

"....the answer is that this is the Mercruiser fuel-injected MX 6.2L. It is pretty fuel-efficient. We typically are able to reach WOT 30+ knots and comfortably cruise anywhere from 18-25 knots (usually at the top end of that range). We also routinely waterski or drag other toys behind her."

I don't know how that compared to the 7.4

 

In my opinion, the 280 Sundancer with a single 6.2 small block is underpowered.

That is why Sea Ray discontinued offering this combination.

 

That and they had a 7.4 big block replacement in the 496

 

you gotta love the twin vs single debates

i have twins and its twice as much everything

 

Just in case others read this then think I am saying all single engines do not have enough power for the 280 Sundancer, that is not what I am saying.

Here is my opinion as it relates to the Sea Ray 280 Sundancer:

The GM 8.1L = 496ci = “big block V8” products a lot of tork (lower RPM power) and can get this boat to gitty up quite well.

The GM 7.4L = 454ci = “old big block V8” in my opinion did OK and so long as you are at the lighter end of the passenger and gear onboard and lower end of the performance expectations. This engine is acceptable.

The Mercury 6.2L =377ci = “small block V8” an engine that begins life as a GM 5.7L that mercury tweaks. Mercury actually did a pretty good job; actually mercury did an excellent job at tweaking this engine. They got it to pump out 320 horse power, more horse power then the 7.4L big block V8 and 20 more horsepower then the GM 5.7L small block V8 but the engine has a Achilles' heel.

To understand the Achilles heel you need to understand horse power. Horse power is tork times RPM. The 6.2L is a ‘relatively’ high revving engine at 5200 RPM vs 5000 for the 5.7L small block V8.

Mercury will never publish a tork curve like GM does on its engines. But I (and many others) know where Mercury found those extra 20 ponies. They are at the very top of the chart, right at the RPM limit. At lower RPM’s the tork is about the same at the 5.7L small block V8.

So if you put this engine in a heavier boat and you are trying to get on plane, it’s not horse power at wide open throttle that is going to get you on plane because the engine is not at maximum RPM at those speeds, it’s the tork.

So the top speed on a 280 Sundancer with the 6.2L small block V8 will be pretty good compared to the 7.4L big bock V8 but you will always need a light load to get on plane.

This engine is good for dock queens, and there is nothing wrong with that. I know a family with a big boat that has not had a working engine for the last several years. The boat is there vacation home.

If you plan on going boating with other people, the 6.2L small block in this heavy of a boat is under powered in my opinion.