Better get a better source there Paully ;)

agreed

sounds like a load!

2 outboards of the same hp as one single motor won't push a boat as fast.

i no they were trying to stop people using winches and tippers but that was only talk that didnt get passed through the system. as for the motors i would think so it would just be twice as reliable in case one shit itself.

I believe there is some truth to the twin outboard notion, maybe not that much, but sharing common elements like hull / leg friction and cav plate influence - with a few beers I'd believe it for sure! the power gain is probably over ruled by the weight difference tho eh? is two smally's heavier than one biggy?

The interesting thing is, it was a boat salesman (as good as a car salesman I guess!!!) who told me about the outboard theory, although as I said it was a long while ago. It's also surprising how many amateurs that i have talked to think the winch and tipper is illegal.  

thats really wrong.

2 x 100hp outboards has the same output as 1 x 200hp outboard, although HEAVIER and MORE DRAG, and therefore not as quick.

2 x outboards = 2 x engine services a year ($700 ea)

yes, it is a good option if one fails, but that doesnt (shouldnt) happen often if the donks are new, and regularly serviced.

the only advantage to twin motors is the turning circle .. reliability is also but as mentioned you really shouldnt have any drama's anyway with new motors and with the safety gear now days. twins will run slower and use more fuel when compaired to a single of the same rating. as a rule 2 x 100hp motors = 175hp single.  

correct me if Iam wrong I think you might find the winch will be a hydraulic system run off the main

i would agree with Feral about the twin outboarbs. you only get equiv to around 75% to 80% of the total hp output of the motors combined but you will use a lot more fuel and as mentioned it will cost double for services

for your words of wisdom, always good to hear your thoughts and have these strange sort of questions answered.

Think the same as Feral and FF, but these are just my thoughts:

I am pretty sure that the boat salesman has mixed up Pythagoras' theory of a2+b2=c2 (the triangle sides one) with Logarithmic Scale.... but he is doing a great job as a salesman!!!

I think that if you have a boat with 175hps that can do 40 knots putting on a second motor with 175hps wont make you go 80 knots and wont give you 435 hp's... I think it is more like  2 x 175hps would give you 2 lots of 175hps which does add up to 350, but on the water it would be more like 330.

Like if you have two stereos playing at 80 decibels it doesnt make it 160 decibels... it is more like 83db.  

I think someone might have to call Dr Karl on JJJ this thursday with this one just to double check.

Would love to hear from an expert on this.

You are all labouring under a gross misapprehension. My current boat had a 250hp Yamaha 2s single and did 35 knotts WOT. It's gone and I now have 2 x 140 hp Johnson/Suzuki 4s and it does 38 knotts. The dual rig uses much less fuel but they are 4 strokes as opposed to the 2s Yamaha.

Single or double it doesnt seem to make much difference to speed. all of the motors were fitted with stainless props set up so they would all rev to 6000.

Mick

achieving the same speed and of course the extra costs for services, my Blondie question, "Why the hell do you want two motors, is it I can afford two,"  sorry fellas had to ask the question, as our old girl 100hp 17yr old two stroke outboard can still sit on  33knots sitting comfortable coming home on a good sea with two on board and not pushing her, propped for power 17p and if old fart is in the boat alone 20knots coming home on a good sea and still not pushing the old girl, as he has found best fuel usage and motor not working hard 3 and half thousand revs, in a emergency can get 37knots out of the old girl.  Served twice a year when old fart did a lot of fishing, now gets serviced one a year.

Roberta, this is my perspective.

My boat is a 26ft console, with twin 140hp 4stks.

The reason for the twins is turning ability. being able to turn around on the spot is very helpful at times, especially when driving your boat onto the trailer which is what i do, the boats too heavy to winch up.

The new 28ft version of mine that was at the boat show had a single 350 verardo on it, but had to be built with a bow thruster to fix the turning problems.

Everyone talks about reliability and how stable it SHOULD be, but ask the sea rescue crew on here howmany boats get towed back in with a broken down engine, i myself have had to come back once on one engine.

Additionally twins gives more forward push, which gives the boat more stability, and when it leaves the water over a wave, like consoles are made to do :) or is 3/4 out of the water, twins stop the boat from rolling to either side. Trims do a similar thing.

With twin motors the general rule of thumb is you will lose about 25 % total hp. Due to extra weight, drag.

 Out of curouisty a mate had a 26 footer with a single 250hp. He added another 250hp and he picked up 2 knots faster.

He then added 4 feet to the boat and only then did he pick up an extra 15 knots..

Yeah the winch thing never made it into the rule book..

If you can afford 2 motors and you like to (like me) fish in exotic out of the way places 2 is definitely better than one. The reason I went from 1 to 2 is the 250 Yamaha blew to bits at night miles off shore and I needed whitfords sea rescue. The motor was 3 years old and had done just over 300hrs (no explanation). Two weeks before that I was fishing 15 miles south of Steep point at shark bay. UHF is useless down there and VHF not much better. It might have tured out badly if it happened there. All this talk about drag and weight and horsepower is bullshit.

Mick

if we get one power ball yes we'll be buying a 26' Cat with twin what ever motors (that end will be old farts to resolve, I'll just want a toilet in) , just curious as to why, so you've told me, thank's fellas.