posted 07-15-2003 06:02 PM ET (US)            

when I'm ready, I plan to switch to twin screws for two reasons
A) always nice to have a back up motor(even if you have sea tow:)
B) boats handle better with twin screws (that's what I 'm told by twin screw owners, and I've sensed it.

posted 07-16-2003 03:43 PM ET (US)            

The benefits are there as well but as a few others have stated, unless you separate the two engines entirely, the safety of the 2nd motor does not exist. Contaminated fuel on a single tank vessel will affect both motors. To effectively isolate the motors, twin tanks are needed and each tank must be filled up at a different station to prevent filling with contaminated fuel. This is more work than most people will ever do...definitely more than I want to do.

posted 07-16-2003 03:58 PM ET (US)         

1. Twins or a single w/pony motor cost about the same! (seriously)

2. Fuel mileage, comparing engines of same vintage, technology and total HP, will be about the same. It simply takes a certain amount of gasoline (energy) to move a boat, and what it's going through does not make much difference. For long periods of idling in no-wake zones,(such as FL ICW) twins are actually better, since one can be shut down and the other run at an efficient 1400-1600 RPM, with no smoke.
Obviously, a pony motor, gives the best trolling economy, if you don't mind the small engine sound on a big boat (I do).

3. You need a little extra HP rating if you go with twins to achieve the same TOP SPEED as a single. As stated, each twin should meet Whaler's recommendation on minimum to plane the boat, or even a little higher. Full HP rating should always be used, or over. Under powering with twins is a disaster. Only underpower with a single.

4. For manuevering,docking, steering, control in big seas, etc, twins will easily outperform the single. You have two rudders and props in the water aiding control. For some reason unknown to me, boats with twins seem to ride better. Maybe it's the increased stern weight.

5. From a design and appearance perspective, the twin engine Whaler looks great, a Class Act, if the engines are well maintained. A single engine Whaler also looks great. A single engine Whaler with a tilted-up pony motor, off the the side, often a different brand, even if it's not banging around on the transom or some aftermarket lift-up bracket, looks crummy and as an after thought. Sorry guys, but that's how I feel. I know, I had such a set-up on my 16 Nauset, and hated it every minute. I hated how it looked, how it performed, and hated running the boat around 99% of the time with the engine tilted up. It's why my next Whaler (18 Outrage) had twins!

posted 07-16-2003 04:03 PM ET (US)            

The boat built in 1971 was designed to handle 200hp. The biggest outboard in 1971 was 125-135hp in both Merc and OMC. In 72 I believe Merc stepped up to 150hp. Was not until 1976 that OMC came out with a 200, next step down was a 135v4. SO.....you want speed and reliability, ya had to go twins or do 35-40mph with a single.

Janis here has a 1973? with a new 130 Yamaha. She does pretty well, I would say an honest 40mph. The 150 would fetch you another 5-7mph. 200 ponies and you are well above the 50 mark. Would I drop a 200 on one? Only if I knew that 32 year old transom could take what engineers never designed it for. Would I also drop 600lbs of engine on it....sure, but I doubt it. Remember that HP cracks transoms, not weight. Weight effects static trim but those boats are pretty bow heavy to begin with.

posted 07-16-2003 06:19 PM ET (US)            

Interesting topic. I just went through the single vs. twins decision making process on my 23 Walkaround and I'd have to say it was very difficult. After a long and thorough investigation, I opted for a single large outboard with a 9.9 high thrust kicker, and I'm absolutely delighted with my decision. Here's why I chose a single/kicker combo:

A single with kicker was $5,200 less than twins, and then add another $450 for prop and $250 for oil tank (for 2 stroke). Remember - It's very difficult to recoup the money you spend on repowering an older vessel when it's time to sell.

Weight of twins: 475 lbs each = 950 lbs at the transom
Weight of single + kicker = 642 lbs at the transom
308 lbs less.

Maintenance & repair: Double the cost of everything with twins. What if you hit a rock or a log on your lake? With a single, you've only got one motor/prop to repair.

Manueverability: I've operated a Grady White with twins. Docking does not get any easier because there is not enough distance separating the props.

With all that said, good luck with your decision. This website is a great place with lots of knowledgable and skilled boaters who will steer you right.

posted 07-16-2003 06:40 PM ET (US)         

Lets use the 23 Walkaround mentioned above, rated for 400 HP. I'm most familiar with Mercury pricing so I'll use that. But other brands should be equivalent.

OPTION 1:

A single 250 EFI = $12,500
10 HP 4-stroke = $2,500

Total cost $15,000 plus misc fittings, etc required.
Max boat speed about 40 mph. I think this is minimal HP for a boat this size and weight.

OPTION 2:

2 - 125 HP 2 strokes = $6300 each

Total cost $12,600, plus about $400 extra for control over cost of single controls

Here, twins, representing same total HP, are clearly less money, although total power would not be quite as good.

OPTION 3: (best, in my opinion)

2 - 150 HP V-6 2 strokes (carbed) = $7500 each

posted 07-16-2003 09:18 PM ET (US)         

One of the reasons the twins are the same price as a single with pony, is that the big engines, all high tech DFI or 4-stroke, are premium priced, where you can get economically priced twins of same total HP rating. Mercury is the only brand that even offers a conventional EFI 2-stroke above 200HP. If you want a classic 2-stroke 225, 250 or 300, you MUST buy Mercury.

posted 07-16-2003 09:25 PM ET (US)         

OPTION 1:

Mercury 150 = $7500
Merc 4-stroke 10 = $2500

Total $10,000

OPTION 2:

2 - Mercury 75's = $4600/ea
Total cost: $9,200 Twins are actually less here!

OPTION 3:

2 -Mercury 90's = $5,000/ea
Total Cost: $10,000

posted 07-16-2003 10:35 PM ET (US)            

Twin V-4s would have 8 spark plugs; a V-6 and a kicker about the same, 7-8 plugs.

Replace water pump impeller; you have two lower units to replace in either case.

But here is an advantage with twins: if you have a problem with one engine, you can use the other for comparison. Want to check some voltages? You've got a good engine to use for comparison to the bad engine. Want to swap a part to see if that fixes it? You have a good engine with good parts to test with.

posted 07-17-2003 01:30 AM ET (US)            

Today, to replace the current motors with California legal versions of the same power, that weight goes up to 608 pounds (497+111)for a 200 Optimax and 15 4-stroke kicker. This is still below 700 pounds, but it's like having a 125 pound kid sitting on my outboard all day long. Feet probably stay dry unless there's two of us standing near the stern. If I go with a 4-stroke Merc 200 instead of the Optimax, I'm up to 694 pounds (583+111), right at the limit for transom weight with just a single and a kicker.

Twin 115 Optimax's will put 750 pounds(2x375)on the transom, so my feet are wet, the deck is flooded and I'm using plugs in the sumps and some pumps to keep things dry. The boat looks stern heavy, and I have to repaint my waterlines. Also, I'm nervous because a few recent threads have indicated problems with plug fouling at trolling speeds and overheating when going on plane after extensive idling or low speed running. Whaler says my Outrage 22 Cuddy will plane on 90 hp with a light load, but I don't know if the prop on the twin setup will get me there.

If I go with twin Mercury 115 4-strokes, I'm now hanging a whopping 772 pounds (386x2) off the back, well over the max suggested by Whaler. I've lost my console space by putting my batteries inside it, and the boat looks like it's doing a wheelie at rest.

posted 07-22-2003 08:35 PM ET (US)            

Here's my point; if your planning to switch to twins, your first consideratio should be weight. In other words, buy the lightest package that will provide the desired horsepower. In most cases twin four strokes are just too heavy and you'll be dissatisfied with the results.

From my experience, the only models I would recommend twins for are the V hull 18/19 Outrages, the 25' hulls, and all sizes of the Whalerdrive models. (the 20 and 22 whalerdrives will also do fine with a large single). With a Whalerdrive it is possible to increase the horsepower enough to make twin engines worthwhile.

On the smaller boats it is possible to achieve the same horsepower with single or twins. Since the single configuration is lighter, it will offer higher top speed and better economy. The twin configuration will offer a better hole shot and marginally better handling (except for the 18 which sees a substantial improvement due to the spacing of the engines).

In addition to the cost of engines you also have other added costs. You may have to upgrade your steering system to handle the extra weight. A tie bar kit will run you $100 - $200. Then there's extra controls, cables, gages, fuel lines, and of course double the maintenance.

posted 07-01-2004 11:22 AM ET (US)            

My first boat (soon for sale) is a 1987 with a single carbed Merc 200 turning a 15x17" Mercury stainless prop. The other is a 1991 with counter rotating twin Yamaha 130s spinning a pair of Yamaha OEM 13x19" (soon to be 21") cleaver props. The engines are all of similar age, and all run well.

The boat with twins fairly leaps onto a plane - the bow come back down in no more than 2 seconds from a dead stop, and top speed is a touch over 51+ by GPS. With the current props I can wind up past red-line, so I'm going to test 21p. I suspect I will loose a little on hole shot and pick up some additional top end. On just a single engine (with the other trimmed out of the water) the boat planes easily and tops out in the upper 30s at 5400 RPM. I typically cruise ~3800-4300 RPM at 30-35 mph. I find the engines fairly easy to sych by ear, and the ability to trim the engines independantly obviates the need for trim tabs.

The '87 with the single 200 planes more sedately (though certainly adequately), and tops out ~ 42mph, but it has a T-Top which I suspect steals ~3 mph. Oil tank and battery in this boat are in the console, so it sits with a much more neutral static trim than the boat with twins (~445 lbs on the transom, vs at least 800 for the twins including props, a pair of batteries and oil tanks in the splash well.)

I boat in some fairly out-of-the way places (no sea-tow, or anything like it - if you call the coast guard, they will come get you, but leave the boat) on a very unforgiving body of water (Lake Superior - check out live surface temp in the open lake here http://www.ndbc.noaa.gov/station_page.phtml?$station=45006 , so the added security of twins was very, very important to me. If all oif my boating was in well-traveled, warm water locations, I might lean more towards the large single option from a purely practical perspective.

posted 07-01-2004 08:17 PM ET (US)            

I´ll put it simple: even if your single engine don´t brake down NEVER, you will ALWAYS go out with more confidence and more relaxed (with twins). And that is why you want to go out in the first place.