On Sep 7, 10:41 pm, wrote:
On Sep 7, 10:12 pm, wrote:



On Sep 7, 10:07 pm, hk wrote:

wrote:
I was at the springs at the head of he Wacissa River this afternoon
cooling down on a hot Sept afternoon. From far away you could hear it
coming upriver, another airboat. I hate the damn things. I dont hate
em for going places, I hate the noise. So, is it the prop or engine
that makes all the noise? Could you maybe make an effective prop that
would be less noisy?

Get a noise ordinance passed and get it enforced. That's what we did
where I lived in Florida. No airboats before or after certain hours of
the day. We also made a stink about the damned things cruising over and
cutting swaths through the wetlands.

I think they like the noise. Same sort of guys as the ones who remove
the mufflers on their motorcycles and put straight pipes on the little
Japanese cars. Big noise, small dick.

You may be right about them liking the noise. Maybe this is a techno-
opportunity to find a way around the noise generation. A little
searching shows that major noise is from the prop although many boats
have unmuffled engines too. I wonder if putting a cowling around the
prop would work, somebody must tried this.

Found a DTIC report (that I do not want to pay for) saying that a
cowling and redesigned multiblade prop will reduce prop noise.
Another report from the nature Conservancy discusses noise and finds
that muffling always helps some. They also say that noise is worst at
high prop tip speeds so it is best to go with a multiblade prop.
Worst noise whn one is attempting to get underway from land or sandbar
or to get unstuck.
So, is this an opportunity for someone to make composite airboat props
with multiple blades to replace all the old ones with two blades?

I cannot jump on these airboat ppl too much for being ignorant
rednecks, partly because I ma probably related to em and partly
because airboats do have good uses. The Wacissa is a place for em as
the water is often so shallow and covered with hydrilla. It would
really make people like them if the noise could be significantly
reduced. They seem to have enough power to be able to reduce noise
somehow. Maybe radically re-think the whole concept. At very least
put cowlings around the blades so the noise goes up or back rather
than be emitted in all directions.