Conference vicki::boats

    The last summer's version went into the ComProps. Some poor guy
    seemed to have wasted some good money ( a days gas worth--for a
    small craft ) on the prop, finding out that it was trash. Not solid
    enough to ever get out to "cruising" pitch. So, the engine could
    red-line, quite easily. 
    
    Mike

    I meant to say, "last summer's version of POWERBOATS" in .1.

    I have seen the Comprop and several other clones.  They do
    not look impressive.  I was told that they are primarily
    intended as emergency spares.  However, the advertising
    you quoted certainly doesn't give that impression.

    There is another manufacturer Propulsion Industries, which
    makes PIGI Props.  These are made from "DuPont non-metallic
    composites", and are more expensive (list $120).  They
    are available for most I/Os and outboards in standard,
    cutter and cleaver.

    I saw them at the Ft. Lauderdale boat show, and they look
    just like an aluminum prop.  Their claim to fame is that
    the prop is supposed to shear in a collision before drive
    train damage can occur, while being intended for full time
    (not emergency spare) use.

    I would like to try one of these, now that I live in a world
    of rocks.  I believe they can be ordered from the
    manufacturer in PR (809) 863-7927.  Their ad shows the
    props being shipped FEDERAL EXPRESS, but perhaps that's
    only to dealers.

    Just as an aside, Boat/US claims in their catalog that they
    can order anything from the manufacturer, even if it's not in
    the catalog.  I called them about the PIGI prop and they were
    less than useless.  The guy I spoke to was fascinated with
    the information I was giving him (so much for knowledgeable
    sales people) and told me that even if they wanted to, it
    would be a year before they could sell the prop.  I guess
    'special orders' only refer to companies they already do
    business with.

    I was speaking with a fellow I know who builds patrol boats. ie:
    27 ft with twin 200's on brackets. These boats are used by gov't
    for various costal duty. He set up a boat with Pigi props last week
    and has sea trialed the boat, No unusual problems with the props.
    
    The cost is in line with a stainless prop, and it has the advantage
    of shearing on impact. So having spares on board is essential.
    
    As far as running on a sheared prop, It is not a good idea for any
    engine; As the vibration of a broken prop will quickly ruin the
    bearings in the engine.
    
    A comment on that US/Marine- I went there yesterday to buy a dingy.
    Same inflatable that Bliss has for $735. US/marine had priced for
    almost $900.  The salesman didn't know his a-s from his elbow and
    would not budge from list price.  I guess he didn't need my money??
    
    

��-< But Plastic should be cheaper??? Right?? >-

    I guess it's supply and demand.  I just tried to buy a PIGI
    prop, and their production is sold out for at least a month.

    I wanted a 13x19 standard prop for a MerCruiser.  The price
    is $115 including shipping.  (Which is more than list price
    for the same MerCruiser prop in Aluminum.)

    The East Coast distributor is in Pennsylvania:
    	East Coast Propulsion
    	Steve Burakiewicz
    	(215) 533-8621


    	- Lee

    I recently purchased a PIGI propeller, and tried it out last
    weekend.  It worked as expected -- no discernible difference
    from the aluminum prop.  (My goal was to have something which
    would shear before the driveshaft if I hit a rock.)

    I'm planning about 200 miles of cruising for Labor day
    weekend, so that should be the 'acid' test.

    As an aside, the distributor told me an interesting story.
    Apparently Yamaha is besieged with bogus warranty claims on
    lower units (boaters hit things, replace the prop to conceal
    the damage, and then try to get repairs under warranty). 
    According to the distributor, they just received a big
    contract from Yamaha to provide original equipment props.

    	- Lee

    Moved by mod...   See also note 231.
    
================================================================================
Note 957.0                       Piranha Props ?                      No replies
POLAR::MONTEITH                                      17 lines  25-MAR-1992 12:01
--------------------------------------------------------------------------------
Fellow Boaters,
       
     	Some previous notes talked about graphite composite props,
    unfortunately, the overwhelming response was that these were only 
    good in an emergency situation. 

	I read an article in a Power Boating Canada magazine about a
    composite prop that provided the same "Out of the Hole" performance,
    and added about 1 MPH to the top end, this was compared to an equivalent
    aluminum. This, and the fact that you could simply replace one cup
    (bucket) at a time, if required, for about $15-$20, made it sound quite
    attractive.

	Sounds a little good to be true, they called it a Piranha. Anyone
    heard of it ?
                                  
Rock Shy Rob   

                              -< Piranha Props? >-
<	I read an article in a Power Boating Canada magazine about a
<    composite prop that provided the same "Out of the Hole" performance,
<    and added about 1 MPH to the top end, this was compared to an equivalent
<    aluminum. This, and the fact that you could simply replace one cup
<    (bucket) at a time, if required, for about $15-$20, made it sound quite
<    attractive.
<
<	Sounds a little good to be true, they called it a Piranha. Anyone
<    heard of it ?
                                  
After trashing 2 aluminum props in 1 day, 1 on rocks & 1 on floating/submerged
wood (I think), I purchased one of these PIRANHA props.  The hub is aluminum
with composite end caps (both ends of the prop) and 3 composite blades that fit
into tapered slots in the hub.  The complete assembly was $99.95 + shipping ($8
in this case because I was in a hurry) and $16.95 + S&H for replacement blades.
The end caps are each held in place by a trio of 3/16" alignment pins which fit
into mating holes in the hub unit and, of course, the prop nut. 

After putting it on my 75hp Mariner OB, I noticed I got about 300 rpm more than
with the same pitch aluminum prop (the PIRANHA is cupped, my Aluminum was not),
but did not notice any increase in top end (however my speedo's kind of shakey.)

The hub is guaranteed for manufacturing defects for 1 year, the blades for 30
days.  Breaking a blade on an obstruction is not covered in the warranty. 

Whereas I haven't hit anything with it yet and I've only had it on the boat for
about 4 hrs use, the jury is still out on whether or not this was a wise
purchase and whether this is a decent prop.  As a bass fisherman, I get in close
to the rocks all the time, so it's only a matter of time before I hit something
again.  A big unknown to me is how the prop blade will break when I next bang
a rock.  Aluminum props take out a chunk and steel props bend. Will the 
composite prop shatter, chip, or take the abuse?

If I have any problems with it I'll make another entry. 

Al

    	Composites tend to self destruct once their modulus of elasticity
    is exceeded.  With this in mind I would expect that they will probably
    shear off at the weakest point.  This may not be where you think a
    slight problem in the building process can result in weak spots in
    weird places.  Hope you ordered a couple of spare blades to carry in
    your on the water repair kit.

    	If you do serious damage to metal propellers on a regular basis
    this sounds like it could be a good deal.  If on the other hand you
    almost never expensive damage to propellers then it does not seem like
    a good deal.  In your case it sounds like it may pay off.

    Forrest

    Al, why don't you let me borrow your boat so we can get the evaluation
    of this style of prop completed.  Inquiring minds want to know!  :-)
    Since I don't have a vested interest in your boat, I won't mind running
    it over some rocks for you so we can see what happens to the prop/lower
    unit.
    Wayne

<    Al, why don't you let me borrow your boat so we can get the evaluation
<    of this style of prop completed.  Inquiring minds want to know!  :-)
<    Since I don't have a vested interest in your boat, I won't mind running
<    it over some rocks for you so we can see what happens to the prop/lower
<    unit.

	Thanks, Wayne,  you're all heart...

Al

    My neighbor's conclusion on these composite props was that they are
    simply "for emergencies". He destroyed his in 2 outings.
    

    I managed to use a PIGI prop for a whole season.  However,
    when I was backing the boat (on the trailer) into the barn,
    the back up the barn rushed up unexpectedly, and hit a prop
    blade on the tilted outdrive.  Fortunatly, the blade snapped
    off, rather than the barn wall falling down.

    I guess the prop did provide protection, just not from what I
    was expecting.

re: Note 44.12  
>> My neighbor's conclusion on these composite props was that they are
>> simply "for emergencies". He destroyed his in 2 outings.
   
Without more facts, your neighbor's conclusion means nothing.  If it
was destroyed from normal use then he's right.  If it was destroyed
because he continued to hit things, then I'd say the prop did its job
and shouldn't be condemned.

Rick

    
    	re: comp props for "backup" only
    
    	ayup as far as I'm concerned with the COMPPROP or whatever
    	they called it.  Was suppossed to vary pitch to get better 
    	acceleration out of the hole then handle the higher speed.
    	
    	My Comprop gave me terrible get up time and knocked about 
    	10mph off my top end on a 17' MFG bowrider with 100hp Johnson
    	outboard (about 4-5 yrs ago ...)  It was really only an 
    	emergency prop and really, for the same price I could have gotten
    	a rebuilt aluminum.  (I sent it back).
    
    	The Pirahna is of course newer technology and it sounds a lot
    	better than the comp prop of old, since it at least seems to 
    	meet std prop performance.  That's a real good start for 
    	composite construction.  
    	
    	Since they will self destruct and thus leave you in the deep 
    	without a wheel ... spare wings are required or a spare alum
    	prop to get you home.  I expect a hit to cause more damage than
    	on a metal prop that might shake, but will get ya home.
    
    	Tell us more as you work the bugs out ... sounds better than
    	the past units.
    
    					- Ed

    re:.14
    
    The tributaries of the Chesapeake are known for the varying bottom
    depths. Not many rocks but mostly sand and soft mud. If you have ever
    seen a chart of Kent Narrows (near the Bay Bridge, you would know what
    I mean). Scrapping bottom is a given down here. With metal, you rough
    up the edges of your prop. With composite, well...

    I don't recall seeing the comp props being offered in any of the big
    pitch sizes, 19" is the biggest I beleive. That leads me to think they
    can't handle the torque of a bigger engine without shearing their
    blades off.
    
    Just an observation.
    
    ~jeff