# Left vs Right **URL:** \ **Category:** Factual Questions\ **Created:** [July 5, 2001, 1:38am UTC](https://boards.straightdope.com/t/left-vs-right/71277 "2001-07-05T01:38:12Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![ISBop](https://avatars.discourse-cdn.com/v4/letter/i/bc79bd/32.png) [@ISBop](https://boards.straightdope.com/u/ISBop)\ **Post date:** [July 5, 2001, 1:38am UTC](https://boards.straightdope.com/t/left-vs-right/71277/1 "2001-07-05T01:38:12Z")
Why do most cars built in America have the steering wheel on the left, but most boats (personal ski-boat type things) have the wheel on the right side? ---
**Author:** ![Sublight](https://avatars.discourse-cdn.com/v4/letter/s/439d5e/32.png) [@Sublight](https://boards.straightdope.com/u/Sublight)\ **Post date:** [July 5, 2001, 2:05am UTC](https://boards.straightdope.com/t/left-vs-right/71277/2 "2001-07-05T02:05:30Z")
From the Straight Dope Staff: [http://www.straightdope.com/mailbag/mdriveboat.html](http://www.straightdope.com/mailbag/mdriveboat.html) Actually a pretty interesting answer. The torque from the clockwise-turning propeller on older boats would cause the right side to rise up. The weight of the driver would counterbalance this. Modern boats don’t have this problem, but the design is still used. –sublight. ---
**Author:** ![Sublight](https://avatars.discourse-cdn.com/v4/letter/s/439d5e/32.png) [@Sublight](https://boards.straightdope.com/u/Sublight)\ **Post date:** [July 5, 2001, 2:09am UTC](https://boards.straightdope.com/t/left-vs-right/71277/3 "2001-07-05T02:09:36Z")
As a follow-up question to the SDStaff article, why was this a problem on older boats, but not newer ones? –sublight. ---
**Author:** ![sewalk](https://avatars.discourse-cdn.com/v4/letter/s/b3f665/32.png) [@sewalk](https://boards.straightdope.com/u/sewalk)\ **Post date:** [July 5, 2001, 7:09am UTC](https://boards.straightdope.com/t/left-vs-right/71277/4 "2001-07-05T07:09:15Z")
If you read all of the linked article, > [@](#): > > …used to be designed in such a way that when there was torque on the prop, the right side of the boat would rise up. you can infer that hull designs are now more efficient at counteracting prop torque. Not being a naval architect, my WAG would be that since most boats today are tri-hulls, this shape resists rolling better than the old simple hulls common when powerboats hit the market 50 years ago or more. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [July 5, 2001, 8:15am UTC](https://boards.straightdope.com/t/left-vs-right/71277/5 "2001-07-05T08:15:24Z")
If you **really** read the whole article, it specifically says “[t]his is not a problem with modern hulls,” indicating that the problem has indeed been solved by improving hull shape. So, why do all propellers turn clockwise? And is it true that on dual-propeller boats, the propellers turn opposite ways? ---
**Author:** ![Sublight](https://avatars.discourse-cdn.com/v4/letter/s/439d5e/32.png) [@Sublight](https://boards.straightdope.com/u/Sublight)\ **Post date:** [July 6, 2001, 1:24am UTC](https://boards.straightdope.com/t/left-vs-right/71277/6 "2001-07-06T01:24:05Z")
Ok, let me restate my question. **Yes,** I read the entire article. From it, I inferred that the problem had been solved by improving hull shapes. What I wanted to know was, what _kinds_ of changes were made to the hull in order to counteract propeller torque. **sewalk’s** answer about the tri-hull design sounds reasonable. Is there anyone out there who can offer more than a WAG? –sublight. ---
**Author:** ![Neurodoc](https://avatars.discourse-cdn.com/v4/letter/n/848f3c/32.png) [@Neurodoc](https://boards.straightdope.com/u/Neurodoc)\ **Post date:** [July 6, 2001, 3:45am UTC](https://boards.straightdope.com/t/left-vs-right/71277/7 "2001-07-06T03:45:54Z")
A more interesting question would be why US and most European autos (excepting Great Britain) have the steering wheel on the left. Japan follows GB on this. Homo sapiens is the only bilaterally symmetric species that exhibits “handedness,” so this is indeed an interseting question. Since right/left handedness is fairly consistent across human ethnic groups, it might be worthwhile to determine whether the right or left placement of the steering wheel is “more fit.” Say by comparing auto accidents in right v. left steering wheel countries. Has this been attempted? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 6, 2001, 4:49am UTC](https://boards.straightdope.com/t/left-vs-right/71277/8 "2001-07-06T04:49:59Z")
> [@](#): > > Homo sapiens is the only bilaterally symmetric species that exhibits “handedness,” so this is indeed an interseting question. So, [cats](http://www.straightdope.com/classics/a4_085.html) aren’t bilaterally symmetric? ---
**Author:** ![tomndebb](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@tomndebb](https://boards.straightdope.com/u/tomndebb)\ **Post date:** [July 6, 2001, 5:41am UTC](https://boards.straightdope.com/t/left-vs-right/71277/9 "2001-07-06T05:41:49Z")
> [@](#): > > A more interesting question would be why US and most European autos (excepting Great Britain) have the steering wheel on the left. Japan follows GB on this. More intersting? Perhaps. Already answered? Of course! The Master _has_ answered the question [Why do the British drive on the left?](http://www.straightdope.com/classics/a3_021b.html) As to your followup question regarding the inherent safety of one mode or the other, I doubt that anyone has done such a survey. On the other hand, the results would be open to so much squabbling over the perceived bias against whichever method was deemed less safe, that more people would probably die in the ensuing feud than would be saved by forcing the adoption of one practice universally. ---
**Author:** ![Neurodoc](https://avatars.discourse-cdn.com/v4/letter/n/848f3c/32.png) [@Neurodoc](https://boards.straightdope.com/u/Neurodoc)\ **Post date:** [July 7, 2001, 4:14am UTC](https://boards.straightdope.com/t/left-vs-right/71277/10 "2001-07-07T04:14:09Z")
> [@](#): > > \*Originally posted by Chronos \* > \*\* > > > [@](#): > > > > Homo sapiens is the only bilaterally symmetric species that exhibits “handedness,” so this is indeed an interseting question. > > So, [cats](http://www.straightdope.com/classics/a4_085.html) aren’t bilaterally symmetric? \*\* Chronos: Of course cats are bilaterally symmetric. But, as I said, they do not show any species preference for forelimb manipulation. No other vertebrates besides humans show such a preference. I’m surprised you missed my point, especially since you are an SD “moderator.” ---
**Author:** ![Orbifold](https://avatars.discourse-cdn.com/v4/letter/o/779978/32.png) [@Orbifold](https://boards.straightdope.com/u/Orbifold)\ **Post date:** [July 7, 2001, 6:46am UTC](https://boards.straightdope.com/t/left-vs-right/71277/11 "2001-07-07T06:46:43Z")
> [@](#): > > \*Originally posted by Neurodoc \* > \*\*Chronos: > > Of course cats are bilaterally symmetric. But, as I said, they do not show any species preference for forelimb manipulation.\*\* Considering that the column he linked to directly contradicts the above statement (i.e., two-thirds of the cats in the study were “left-pawed”), I think **Chronos** got your point just fine. You may, however, have missed his. ---
**Author:** ![Orbifold](https://avatars.discourse-cdn.com/v4/letter/o/779978/32.png) [@Orbifold](https://boards.straightdope.com/u/Orbifold)\ **Post date:** [July 7, 2001, 6:48am UTC](https://boards.straightdope.com/t/left-vs-right/71277/12 "2001-07-07T06:48:46Z")
Whoops…two-thirds of the cats who displayed a preference, I should say. Must be time for me to go to bed. ---
**Author:** ![Chronolicht](https://avatars.discourse-cdn.com/v4/letter/c/3bc359/32.png) [@Chronolicht](https://boards.straightdope.com/u/Chronolicht)\ **Post date:** [July 7, 2001, 6:58am UTC](https://boards.straightdope.com/t/left-vs-right/71277/13 "2001-07-07T06:58:45Z")
Perhaps to test the question, we should put Ralph Nader and Al Gore in their respective SUVs, one left hand drive and one right, and crash them into each other at high speed. ---
**Author:** ![Neurodoc](https://avatars.discourse-cdn.com/v4/letter/n/848f3c/32.png) [@Neurodoc](https://boards.straightdope.com/u/Neurodoc)\ **Post date:** [July 8, 2001, 6:34am UTC](https://boards.straightdope.com/t/left-vs-right/71277/14 "2001-07-08T06:34:13Z")
Considering that the column he linked to directly contradicts the above statement (i.e., two-thirds of the cats in the study were “left-pawed”), I think **Chronos** got your point just fine. You may, however, have missed his. \*\* [/QUOTE] There are several good texts that discuss the subject of lateralized behavior in vertebrates, including paw preference in rodents, cats, dogs, and reaching preferences is apes, etc. A good general test is “The Lopsided Ape.” You and Chronos are mistaken in your assertion that non-human vertebrates exhibit significant left-right asymmetry for manipulative asymmetry and cerebral hemispheric functioanal asymmetry. Actually, Chronos may not be assumed to be mistaken, since he merely referred to the bilaterally symmetric body plan of cats. Cheers, Nick Capozzoli, MD ---
**Author:** ![Chronolicht](https://avatars.discourse-cdn.com/v4/letter/c/3bc359/32.png) [@Chronolicht](https://boards.straightdope.com/u/Chronolicht)\ **Post date:** [July 8, 2001, 6:54pm UTC](https://boards.straightdope.com/t/left-vs-right/71277/15 "2001-07-08T18:54:44Z")
Please explain bilateral symmetry of cats. ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [July 8, 2001, 8:31pm UTC](https://boards.straightdope.com/t/left-vs-right/71277/16 "2001-07-08T20:31:27Z")
scr4: > [@](#): > > So, why do all propellers turn clockwise? And is it true that on dual-propeller boats, the propellers turn opposite ways? Boat propellers normally turn clockwise because most engines do. Why this is I don’t know. And yes, on all twin engine boats (not including ones with twin **outboard** motors) not only do the propellers spin opposite ways, the engines do. Making an engine run ‘backwards’ isn’t as hard as you might think. All you do is put in a different cam and starter. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [July 8, 2001, 10:34pm UTC](https://boards.straightdope.com/t/left-vs-right/71277/17 "2001-07-08T22:34:42Z")
just to add to what hail ants said - outboards too can be counterrotation and usually are with high HP motors (you have to) but IIRC they make counterrotation outboards as low as 25hp. ---
**Author:** ![Orbifold](https://avatars.discourse-cdn.com/v4/letter/o/779978/32.png) [@Orbifold](https://boards.straightdope.com/u/Orbifold)\ **Post date:** [July 9, 2001, 3:52am UTC](https://boards.straightdope.com/t/left-vs-right/71277/18 "2001-07-09T03:52:23Z")
> [@](#): > > \*Originally posted by Neurodoc \* > **There are several good texts that discuss the subject of lateralized behavior in vertebrates…** Well if you have other information that’s a whole other story. However, your previous post gave the impression that you hadn’t even followed the link Chronos provided, which was challenging your assertion and not “missing the point” as you claimed. [shrugs] All the same to me. ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [July 9, 2001, 6:14am UTC](https://boards.straightdope.com/t/left-vs-right/71277/19 "2001-07-09T06:14:27Z")
Yes, a 2-stroke motor would be even easier to run backwards, if it had reed valves instead of a cam. Just crank it that direction and it’ll start. Come to think of it, I remember hearing about an old model outboard motor that did just that instead of having mechanical reverse gears. It became known as ‘The Dockcrusher’ because you’d be coming towards the dock, turn it off, try to start it in reverse and, **“RRRRRRRR RRRRRRRR RRRRRRRR SMASH!!!”,** it wouldn’t start back up! ---
**Author:** ![Neurodoc](https://avatars.discourse-cdn.com/v4/letter/n/848f3c/32.png) [@Neurodoc](https://boards.straightdope.com/u/Neurodoc)\ **Post date:** [July 10, 2001, 4:00am UTC](https://boards.straightdope.com/t/left-vs-right/71277/20 "2001-07-10T04:00:50Z")
> [@](#): > > \*Originally posted by Math Geek \* > \*\* > > > [@](#): > > > > \*Originally posted by Neurodoc \* > > **There are several good texts that discuss the subject of lateralized behavior in vertebrates…** > > Well if you have other information that’s a whole other story. However, your previous post gave the impression that you hadn’t even followed the link Chronos provided, which was challenging your assertion and not “missing the point” as you claimed. > > [shrugs] All the same to me. \*\* Well, I did follow Chronos’ link. There are several studies that show a preference for such elemental functions as “reaching” and “probing” with a forelimb in vertebrates, and even in such bilaterally symmetric invertebrates as crans (think of the Fiddler Crab). What I was talking about is definite “handedness” and cerebral lateralization for manipulative “dexterity.” As regards the aforementioned feline study, the study group was small. Were the animals related. In any case, a mere lateralized paw preference for reaching or poking at objects does not amount to handed dexterity, though it may reflect a left-right asymmetry fundamental to all motile bilaterally symmetric organisms, including planaria… You should pay closer attention to exactly what I say in my posts. I generally chose my statements carefully.