Twin Outboards

[Giant1]

Hi,

this is my 1st post (as you can tell by me posting in the wrong section duh!),

I have had a look at previous posts along this thread but haven't really found anything that totally satisfies my query.

What are the advantages/disadvantages of 2 vs 1 motors? #

I can see fuel consumption/weight/cost/servicing etc. Despite these, if a twin option is offered surely there must be some advantage.

I know this may seem straight forward to some, but the more i read/look, the more confused i get. Anyone's 2cents worth/opinions would be appreciated.

Thanks

PS relating to 685 Outsider or Patriot.

[MulletMan]

One myth is that you have double the horsepower i.e. 2 x 115 HP = 230 HP = WRONG!
There is a formula that I have long since forgotten to work it out but I am guessing about 15-25% loss of combined power? #:-/

The main reason for this is that often the donks are placed together (on a mono) and the disturbance of the two propellors reduce the efficiency of the water flow. :-/

Talking props, you also need one to be contra rotating eg. One goes clockwise and the other anticlockwise. Lash out and get two decent SS cupped props - worth every cent. #:D

If you have say 1 x 135 HP then by using it sensibly you may be slightly ahead fuel wise compated to say 2 x 50 HP. I am sure some of the guys here will have experience in this sort of stuff.

Of course, the ultimate safety you achieve by the two motors is a huge plus! If you intend to operate in areas where help is not rapidly available or offshore where one broken down single motor gives you that very lonely feeling, then two is the go. #;D

A well looked after and maintained outboard (go the 4-strokes) is very reliable and many guys have no qualms in going offshore with them. ;)

You also have to check the maximum allowable weight and horsepower that your boat can legally carry. Usually this is on a stamped plate somewhere on the transom. Two motors can be pretty heavy and the last thing you need is for the transom to let go. #:'( :'(

Spend heaps on dual 16 plate batteries with a Smart Charger.

[revs57]

TPP has covered most of the aspects Giant1.

With Twins you also get more lift from the 2 props, it gets up quicker and have the benefit of being able to control the trim through each motor. No need for trim tabs. Although it does add weight to the transom which can come into play if you beach launch or use shallow ramps

You also gain manouverability in tight spots, forward on one motor and reverse on the other.

My mate has twin 140 'zuke 4 bangers and gets better fuel economy than my single 150 2 stroker EFI. Get the obvious benefit of safety but at the expense as you mention of an extra motor to service.

But none the less I'm seriously weighing up changing the Flamin Riptide to twin 115's or a single 175 'zuke in the future

Cheers

rhys

[Thebuffalo]

Our boat here has two motors. It has saved the bacon a couple of times. Had a wave come over the bow the other night which managed to put one out. Don't ask how, it was electrical. They got home fine. Remote areas I think it is the wise choice if you can afford it. Generally thought the reliability of singles is pretty good. Most have a limp mode. Buy a decent auxillary and you have piece of mind and a little motor for trawling. This said I would have two if money was no problem.

Cheers

[mcgilld]

Google: Chapter 1: Choosing an outboard (by David Pascoe).
It's an excellent article with a good section on single v twin.
I can't find the link right now...

[catchy_fishy]

If I understand your question, as the simplicity of it alone has caused me some confusion I believe you are asking why would a person have 1 outboard engine, or two outboard engines ?

Would that be right ?

If I've missed the proverbial "boat" my apologies, but here are a few thoughts as to why have two outboards.

1. First and foremost is safety

Should one engine fail you have a reliable way of getting out of trouble, and do not need to revert to safety procedures immediately

2. Distance off shore

Bigger fish further out
Not sure about your regulations but in SA, one may only travel 5nm with 1 engine, with 2 one can travel 15nm. (certain other conditions to go further).

Irrespective of regulations you can safely venture out further with more power.

3. Power / Speed

Ability to turn on/through weather and head home quicker than with 1 engine

4. Fishing

Bigger "bait bubble" from two engines, and one leg can be lifted halfway up while the other is full down to give an even better stream of action in which to troll.

5. Repairs

You have a good refernce guide at home (viz the other motor) if you need to perform repairs to one engine

6. Parts

Parts are interchangeable and while you still end up buying parts for the engine as spares you only need one set at any one time. Hell if the same thing on both engine goes at exactly the same time you could get an entry in Guinness Book of records. (It's probably a bullsh!t excuse but I would add it to the list of pro's anyway)

7. Manouverability

Steering is enhanced by a second motor as acceleration to starboard engine only helps with turning hard, or vice versa. Good for tight turning like running from waves etc if need be

8. Two Batteries

You should wire each engine seperately to it's own battery. All electronics get pulled from one battery only. This is excellent because if one battery goes you also have another battery to jump start from, and recharge while out at sea, or just get you home

Hope it helps.

Maybe others have a few more ideas.

Mike