Was watching Ship Shape TV....

[pstephens46]

It's not about drag racing for me. When you have 7-9 people on board and a bunch of gear, it would be nice to get on plane a little quicker. More efficient. It also would be nice to cruise at a little lower rpm. I'm convinced my boat would be perfect with a V-6. These new, lightweight Mercury 4 strokes may be the ticket. I have no interest in 2 strokes.

[99yam40]

7 -9 people, how big of a boat you pushing?

[pstephens46]

7 -9 people, how big of a boat you pushing?

20ft

You know how wives are. Invite the neighborhood to go to the beach.....

[panasonic]

And they all want to sit on one side or the other, and up moving around while under way...I hate driving a boat all lop sided....lol

[BQUICK]

A lot has to do with flatter torque curves of 2 strokes. 4 cyl 4 strokes are similar to Honda 4cyl car engines. Not much torque until 4000.
V6 or straight 6 4 strokes....now we are talking decent torque.

So what if a motor has *** hp at 6000 rpm. I want to know what it has at 3500-4500 where you cruise.

Too bad manufacturers of outboards don't list torque specs!

[99yam40]

20ft

You know how wives are. Invite the neighborhood to go to the beach.....

Ok I was just thinking we usually had maybe 5 people on some 30 and 40 foot boats when fishing off shore in the GOM

[pstephens46]

Ok I was just thinking we usually had maybe 5 people on some 30 and 40 foot boats when fishing off shore in the GOM

Not every trip....I'm hard pressed to have three people on boat for fishing.

But there are times when it looks, I'm sure, like a refugee boat crossing from Cuba.

[boscoe99]

A lot has to do with flatter torque curves of 2 strokes. 4 cyl 4 strokes are similar to Honda 4cyl car engines. Not much torque until 4000.
V6 or straight 6 4 strokes....now we are talking decent torque.

So what if a motor has *** hp at 6000 rpm. I want to know what it has at 3500-4500 where you cruise.

Too bad manufacturers of outboards don't list torque specs!

They appear to do all they can to avoid providing the curves. Probably because 90% plus of boaters would not have a clue as to what they are about.

[BQUICK]

That would tell the tale....
It's kind of like if you have a 4 cyl car with say 200hp and put 4 fat people in it and it's a slug. But that same car with a torquey V6 with same hp but a lot more torque and at lower rpm and it still pulls.

[zenoahphobic]

That would tell the tale....
It's kind of like if you have a 4 cyl car with say 200hp and put 4 fat people in it and it's a slug. But that same car with a torquey V6 with same hp but a lot more torque and at lower rpm and it still pulls.

That is the crux of the issue. As there is no changing of "gears" in outboards, it is essential that they have adequate low down torque. That is the engine produces adequate power below planning speed to get it over that threshold to run on the plane where initially friction and therefore load is reduced.

So it is also evident that appropriate propulsion via the propeller is equally important, they both (rpm power and prop) have to match the boat load at the planing speed.

[BQUICK]

There were/are some variable pitch props but if they could make a 2 speed gear case or a mini torque converter that would help a lot but the lower unit would be too big most likely.

New cars have more and more gears due in part to low torque high hp motors. There are 8, 9 and 10 speed transmissions ...in cars now. Crazy....

[zenoahphobic]

There were/are some variable pitch props but if they could make a 2 speed gear case or a mini torque converter that would help a lot but the lower unit would be too big most likely.

New cars have more and more gears due in part to low torque high hp motors. There are 8, 9 and 10 speed transmissions ...in cars now. Crazy....

You got to keep in mind that any "gear change" has to occur with power on all the time during the torque conversion process, because boats slowdown very rapidly, some dangerously rapidly, when engine stops. No freewheeling so to speak. But there are infinitely variable boxes out there: like two opposing cones pulled and pushed constantly varying the ratio between them.

[rodbolt17]

for 60K$ you could prolly get a gear shift outboard.
outboards are already stupidly expensive.
why not simply prop it correctly for the load and go enjoy?