Dave: No comments from the peanut gallery.

I'm using the term "speedboats" to describe boats which sound like they have
(and probably do have) a pair of 400+ cubic inch motors in the back? In
order to achieve their purpose (speed), is it absolutely necessary for them
to be as noisy as they are, or are they just designed that way, in the same
way some morons alter their motorcycles because "loud pipes save lives"?
And, when they're idling, why do they sound (and smell) as if the engines
are only firing on half their cylinders?

Well, you've hit on a sore spot with me. Unmuffled engines might gain
2-5 mph on top end, but at the expense of annoying most people at idle
speeds. Ironically, since the exhaust is aimed away from the offenders
cockpit, it is usually of little to no concern to them or their crew.

Most if not all of these boats can elect to install a diverter which
outputs the exhaust under water at low speeds, but for various reasons
(cost, reliability, desire to be a dickhead, etc) elect not to do so.

In the motorcyle world, I'll buy loud pipes save lives as a arguement,
even if its a weak one. In the boating world, with only a modest gain in
performance, I'm guessing some people just need to "compensate for water
shrinkage", but that's just my opinion.

BTW the the pooor idle performance you've observed is a sacrifice to get
higher RPM at top end through more radical valve timing.

Bob Dimond




In article , "Doug Kanter"
wrote:

Dave: No comments from the peanut gallery.

I'm using the term "speedboats" to describe boats which sound like they have
(and probably do have) a pair of 400+ cubic inch motors in the back? In
order to achieve their purpose (speed), is it absolutely necessary for them
to be as noisy as they are, or are they just designed that way, in the same
way some morons alter their motorcycles because "loud pipes save lives"?
And, when they're idling, why do they sound (and smell) as if the engines
are only firing on half their cylinders?

Subject: Loud boats
From: "Doug Kanter"

I'm using the term "speedboats" to describe boats which sound like they have
(and probably do have) a pair of 400+ cubic inch motors in the back?
In
order to achieve their purpose (speed), is it absolutely necessary for them
to be as noisy as they are,

Not necessarily. But exhaust restrictions can lower max horse power.

or are they just designed that way, in the same
way some morons alter their motorcycles because "loud pipes save lives"?

In some cases yes. Except for the "save lives" part.

And, when they're idling, why do they sound (and smell) as if the engines
are only firing on half their cylinders?

Cam timing and lift patterns.

Capt. Bill

"LaBomba182" wrote in message
...
Subject: Loud boats
From: "Doug Kanter"

I'm using the term "speedboats" to describe boats which sound like they
have
(and probably do have) a pair of 400+ cubic inch motors in the back?
In
order to achieve their purpose (speed), is it absolutely necessary for
them
to be as noisy as they are,

Not necessarily. But exhaust restrictions can lower max horse power.

or are they just designed that way, in the same
way some morons alter their motorcycles because "loud pipes save lives"?

In some cases yes. Except for the "save lives" part.

And, when they're idling, why do they sound (and smell) as if the engines
are only firing on half their cylinders?

Cam timing and lift patterns.

Capt. Bill

Are they, in fact, misfiring at idle?

On Mon, 02 Aug 2004 15:41:54 GMT, "Doug Kanter"
wrote:
I'm using the term "speedboats" to describe boats which sound like they have
(and probably do have) a pair of 400+ cubic inch motors in the back? In
order to achieve their purpose (speed), is it absolutely necessary for them
to be as noisy as they are, or are they just designed that way, in the same
way some morons alter their motorcycles because "loud pipes save lives"?
And, when they're idling, why do they sound (and smell) as if the engines
are only firing on half their cylinders?
=====================================

It's just more thoughtless behavior from the ego challenged "look at
me" crowd. There's no reason at all why a pair of 454s has to be
louder than any other well mannered I/O except that the owners prefer
it that way. Unfortunately in their "it's a free country behavior",
they bring down a lot of unwanted attention and enforcement on the
rest of us. Much of the support for "Save the Manatee" madness
originated with waterfront property owners who were fed up with the
constant noise of jet skis and go fasts zipping up and down the
shoreline at high speed (and decibel levels).

The unique stumbling idle is from the use of high performance cam
shafts that are designed to run well only at top RPMs.

"Wayne.B" wrote in message
...
On Mon, 02 Aug 2004 15:41:54 GMT, "Doug Kanter"
wrote:
I'm using the term "speedboats" to describe boats which sound like they
have
(and probably do have) a pair of 400+ cubic inch motors in the back? In
order to achieve their purpose (speed), is it absolutely necessary for
them
to be as noisy as they are, or are they just designed that way, in the
same
way some morons alter their motorcycles because "loud pipes save lives"?
And, when they're idling, why do they sound (and smell) as if the engines
are only firing on half their cylinders?
=====================================

It's just more thoughtless behavior from the ego challenged "look at
me" crowd. There's no reason at all why a pair of 454s has to be
louder than any other well mannered I/O except that the owners prefer
it that way. Unfortunately in their "it's a free country behavior",
they bring down a lot of unwanted attention and enforcement on the
rest of us. Much of the support for "Save the Manatee" madness
originated with waterfront property owners who were fed up with the
constant noise of jet skis and go fasts zipping up and down the
shoreline at high speed (and decibel levels).

The unique stumbling idle is from the use of high performance cam
shafts that are designed to run well only at top RPMs.


Interesting, that last line. Does that explain why some of these boats smell
like unburned gasoline's blarping out of the exhausts, or is that another
issue?

Interesting, that last line. Does that explain why some of these boats smell
like unburned gasoline's blarping out of the exhausts,

That is exactly what is happening. A high performance cam will hold the intake
and exhaust valves open at the same time, longer than a normal cam. (overlap)
At high RPMs when air is flowing fast and plugs are firing 50 or 60 times a
second, that is a good thing but at lower RPMs you are actually sucking intake
mix directly into the exhaust.You can also be popping back through the carb.
You will see the same thing with race cars ...
....and 2 strokes.

I do agree these folks may be calling undue attention to boats. It may be just
a matter of time before we are all running air pumps and catalytic converters.

"Greg" wrote in message
...
Interesting, that last line. Does that explain why some of these boats
smell
like unburned gasoline's blarping out of the exhausts,

That is exactly what is happening. A high performance cam will hold the
intake
and exhaust valves open at the same time, longer than a normal cam.
(overlap)
At high RPMs when air is flowing fast and plugs are firing 50 or 60 times
a
second, that is a good thing but at lower RPMs you are actually sucking
intake
mix directly into the exhaust.You can also be popping back through the
carb.
You will see the same thing with race cars ...
...and 2 strokes.

Great. As if the 100+ decibel noise weren't enough.....

"Greg" wrote in message
...
I do agree these folks may be calling undue attention to boats. It may be
just
a matter of time before we are all running air pumps and catalytic
converters.


I brought up the subject because after being a chauffeur for my 15 yr old
son and his friends for most of the day, I ran out of time to get the boat
in the water. So, I meandered down to the inlet where Irondequoit Bay meets
Lake Ontario. Every 30 seconds, one of these needle-dick boats came blarping
through the inlet. Even at idle speed, it completely drowned out ALL other
sound. I couldn't hear the guy standing 10 feet away from me, who was
yelling about why these dumb boats aren't illegal.