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Author Topic:   Twin engines on 18-Outrage
zpeed7 posted 12-02-2001 11:58 PM ET (US)   Profile for zpeed7   Send Email to zpeed7  
[To LHG:] I was wondering how [LHG's 18-Outrage T/T WHALE LURE] feels with the two 115's in the back... Are they too heavy? Does it sit to low aft? I currently have a 94 150HP Evinrude on my 86 Outrage but I'm toying with the idea of going with twin Yamaha 85's in the future. Would you recommed the twins?

Your boat should be pretty darn fast though...


george nagy posted 12-03-2001 10:17 AM ET (US)     Profile for george nagy  Send Email to george nagy     
zspeed, I hope you don't mind me asking, but what is wrong w/ your engine? what are you going to do with it whwn you repower? I may be interested.
lhg posted 12-03-2001 02:30 PM ET (US)     Profile for lhg    
zspeed - I think my 18 Outrage handles exceptionally well with the twin 115's, and I expect it would also with twins of not less than 60hp also.

Each in-line 6 engine only weighs 305 lbs, and there is no current 115 that is that light. Merc's two stroke 75 & 90's also now weigh 303 lbs. So in my case, engine weight is not a problem at all, and never has adversely effected the handling of the boat. Mine are even set back 10" on transom jacks. See photos in the transom bracket reference section. Since a single 150HP Optimax nowadays weighs 456lb, add a kicker and you're close to the weight of the twin 115's anyway. Obviously, the boat sits a little lower in the transom than it would with a big single on it (see pictures in Rendezvous section), but not enough to be a problem. The boat planes off instantly. I have plugged the three transom drains, and installed an 800gph bilge pump and float switch in the recessed area to get rid of any splash. I like this detail, keeping the spash well dry, which I now use for coolers, bucket or tackle box.

But I don't think I'd want a pair of engines on the boat, at least not on brackets, that were any heavier. This pretty much leaves out the 75-90HP range 4 strokes currently available. A pair of the 60HP 4 stroke EFI's by Merc could be an option, but maybe a touch light on HP for the boat.

So how does it run with the twin 115's? Exceptional, if you ask me, and two other owners of 18 Outrages with single 150's thought the same. That is, they both thought it handled better, rode smoother, had better response and tracked better in big seas. I use bow-lifting Merc Laser II props. It has the feel of a much bigger boat. I think you would be very happy with twins on the boat.

Regarding the HP? Yes, it can go very fast, over 60, but that is not my intention. I usually run the boat between 20 & 35 MPH. Just because the HP is there, doesn't mean it has to be used. And contrary to what most would assume, gas mileage doesn't suffer. It takes a certain amount of gasoline to push a boat a given speed throught the water, no matter what the HP. I get about 3 mpg with the twin 115's at about 25-30MPH. But I'm sure a pair of 60HP EFI 4 strokes would be better, but I'm not sure I'd like cruising at the much higher engine RPM sound.

Blackeagle posted 12-03-2001 05:31 PM ET (US)     Profile for Blackeagle  Send Email to Blackeagle     
lhg - Just wondering how the 18 Outrage performs on one engine. I imagine that one of the 115's can push T/T Whale Lure around pretty good. Any idea how it would perform on one of the smaller engines? (According to the reference article on the 18 Outrage says the minimum recommended is 75 hp).
lhg posted 12-03-2001 05:54 PM ET (US)     Profile for lhg    
The boat will run about 35-38MPH on one engine, with other one tilted clear. (an 18 with single 115 will run about 40) It will plane off with the regular twin engine props, but for trips where I may not be able to get immediate service, and for extended cruising, I carry an aluminum prop 4" lower in pitch.

This is recommended with any twin engine boat where you may have to get along on one engine for any length of time.

I believe that twin engine Whalers should always be powered close to max HP, or a little over, since this will help meet the min-hp-to-plane recommendation. A pair of 90's on an 18 Outrage will not be any faster than a single 150, the boat's rated HP.

Peter posted 12-03-2001 07:03 PM ET (US)     Profile for Peter  Send Email to Peter     
LHG, are the 18's twins counter-rotating? I assume the 25's twins are. If the 18's are not, what is the difference in handling between an Outrage with counter-rotating twins and non-counter-rotating twins? (I realize that there is a length, weight and deadrise difference here.)
lhg posted 12-03-2001 08:07 PM ET (US)     Profile for lhg    
Peter - No, the 115's are not counter rotating, or even oil injected, for that matter. I don't believe anybody makes CR 115's, except for the new Yamaha 115 4-strokes. The 200 EFI's on my 25 are, however.

Until I switched over to Teleflex hydraulic steering, from the original twin cable steering, the boat was a bear to steer, with considerable steering torque. The hydraulic system, as JimH has described in the reference section on transom jacks, completely solved the problem, and there is no torque pull at all. The boat steers like a dream. But the slight torque list exists, so I have gotten used to loading the boat starboard heavy. Other than that, I feel the CR engines would not be necessary, since these are only mid sized gearcase (4 1/4") props.

For anybody planning to power an Outrage with twins, particularly non-counter rotating, hydraulic steering is a MUST have! When I ordered the boat, someone at the factor told me to order the hydraulic upgrade. I didn't take his advice, and paid later! The twin cable mechanical was a beast. Hated it from day one. It finally froze up on me and I made the change to hydraulic.

Counter rotating twins are obviously the best solution. No torque steering pull, or torque list. Really easy to handle even a large boat. CR engines first showed up around 1987, only available in 25" shaft length, and this was the major reason for the introduction of the Whaler Drive - to accomodate this new engine technology, and to get in on the new "bracket craze". But I was surprised to see how many WD boats were equipped with only a single engine, basically giving up everything the WD was specifically design for (increased HP rating to allow for twin 150HP and up CR engines).

So, to answer your question directly, the main difference between the CR and non-CR engines, is absence of torque list, as long as you have hydraulic steering on the non-CR ones.

Peter posted 12-04-2001 09:08 AM ET (US)     Profile for Peter  Send Email to Peter     
Thanks Larry.

Didn't think that the 115's were counter-rotating but I recall someone mentioning that you can might be able to get a counter-rotating foot, although probably not for a 115.

Hydraulic steering is also a good idea to have on a single high horsepowered Outrage to eliminate torque steer. Always had it on my 18 Outrage that was powered by a 150. Wouldn't have had it any other way.

zpeed7 posted 12-04-2001 08:27 PM ET (US)     Profile for zpeed7  Send Email to zpeed7     
Thanks for the info LCG. I'm planning on going with twins on the future because I venture offshore quite a bit and i like the extra security of twins. Does the torque from the engine lean the boat too much to one side or the other?

Thanks again for everything...

lhg posted 12-05-2001 03:02 PM ET (US)     Profile for lhg    
I do not find the propeller torque list to be bad at all, and very easy to counterbalance.
jimh posted 12-06-2001 08:19 AM ET (US)     Profile for jimh  Send Email to jimh     
[Changed thread title for better archival searching; was "A ? for LCG about T/T WHALE LURE"--jimh]
OutrageMan posted 12-06-2001 11:07 AM ET (US)     Profile for OutrageMan  Send Email to OutrageMan     

Aren't you able to get rid of the torque list by putting a little extra trim on one of the engines?


SuburbanBoy posted 12-06-2001 12:17 PM ET (US)     Profile for SuburbanBoy  Send Email to SuburbanBoy     
What about the new 225 4-cycles? They would weigh in at about the same as two of the older 115 straight sixes. And have the advantage of being quieter.


lhg posted 12-06-2001 05:07 PM ET (US)     Profile for lhg    
Brian - Yes, triming with twin engines makes it very easy to eliminate the prop torque.
Another good reason to have them on a Whaler.

Regarding a single Yam 225 4 stroke on an 18, even though I'm hearing that the engine is a performance dog, I still think it would be too much. I even think a single 200 Merc EFI would outrun the twin 115's, since we all know that when going for twins, you need more HP to match the performance of single.

That is why I think a pair of 90's basically equals the same performance on an 18 as a "legal" 150 would give. A pair of 70's or 75's will not keep up with a strong single 150 from what I can tell.

Which brings up another powering rule of thumb. When you're going for twins, never underpower, but instead go for the full boat rating, or even a little over. There is a widespread wrong assumption, in my opinion, that by chosing smaller motors you are increasing fuel ecomony. In reality all the smaller engines accomplish is lower initial cost, and greatly increased wear due to high RPM's. The end result is no saving at all. After several years of long distance cruising with other Whaler acquaintences, with various engine combinations, I am convinced that the laws of physics aren't easily broken, and that it simply takes a certain amount of gasoline to move a boat, a certain speed, through the water, and the size engine it is being burned through does not make much difference. This does assume equivalent engine technologies (but not necessarily same engine brands), however, such as all conventional two stroke, etc. I'm not comparing 2 strokes to 4 strokes.

Here are a few examples, from actual recorded trips and fuel use (about 25-30 MPH):

16 Nauset, with single 115 Merc (6 cylinders): 4.5 mpg

18 Outrage, twin 115 Mercs (12 cylinders total) 3.0 MPG

19 Outrage II, single Yam 150 (6 cylinders total) 2.8 MPG (this rig is about 400LBS heavier than the conventional 18 Outrage listed above)

20 Revenge, twin Yam 70's (6 cylinders total): 2.5 MPG

21 Walkaround, single 200HP Yam (6 cylinders): 2.5 MPG

25 outrage, twin 200 Mercs (12 cylinders total): 2.0 MPG

One would surely guess the twin 70's would give the best mileage. Not true at all.
In order listed, each of these boats is increasingly heavy, and it seems that weight is the predominating factor, on these all similar hull designs. I do still believe that a single is SLIGHTLY more effecient than a pair of twins on economy, but not as much as expected.

Bigshot posted 12-07-2001 10:12 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
My 24' Baja with a 400hp bigblock gets about 3.5mpg at a 35mph cruise at 2800rpm. Moral is outboards(2 strokes) get lousy gas milage.

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