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Author Topic:   Propeller Guards and Navier-Stokes Solutions
pcrussell50 posted 04-15-2010 08:46 PM ET (US)   Profile for pcrussell50   Send Email to pcrussell50  
Someone asked:
quote:
...if you were to simply put a metal tube around the outside of the blades (not blocking the inflow or outflow), it seems reasonable to think that that would not affect the power....would that tube impede the performance of the prop?

Another's reply:

quote:
I don't think it's that simple.

Actually, it IS that simple, and the news is not good. Once you put a tube around the blades, it ruins everything. Everything that moves through a fluid--cars, airplanes, propellers, what have you--creates pressure and flow vector field gradients all the way around it, including, counterintuitively, in front of it. Thus, every shrouded propulsion device I can think of where efficiency matters in the least has a specially designed impeller that is as close as the cost of machining will allow to the shroud's inner surface. This is a major contributing factor to why jet and gas turbine engines are diabolically expensive. It's not unusual for a turbine blade the size of a stick of Wrigley's spearmint gum to cost $12,000 for a single blade. Whenever you are talking about turbo-machinery, which an impeller system almost is, the cost of recovering lost efficiency increases nearly cubically. There are also [concerns] at play here [for the speed of revolution]. That company that makes a pump drive for the Evinrudes that the Marines bought, still uses Evinrude gear cases and propeller shaft speed, which may well be far too slow for efficient operation in that particular disk diameter. In air driven propeller and impeller applications, compressibility, the sound barrier, is a major limiting factor in efficiency improvement. I imagine compressibility would come into play in the design of water-borne systems as well. Would the entirely different flow field calculus of a shrouded propeller or impeller system turn out to be compatible with the operating shaft speed of existing outboards? I lack the [unknown acroynm] software and the ability to solve the relevant (and nearly insoluble) Navier-Stokes equations to tell, but I can guess, and it's not optimistic.

For reference:
http://en.wikipedia.org/wiki/Navier-stokes

The diagram on the first page provides a very intuitive hint at the applicability of Navier-Stokes to this particular problem. If you read further, you will feel my pain when it comes to my gripe about how hard they are to solve by hand, if they can be solved at all.

--Peter

Hoosier posted 04-16-2010 08:19 AM ET (US)     Profile for Hoosier  Send Email to Hoosier     
http://en.wikipedia.org/wiki/Ducted_propeller

The question here seems to be "can a Kort nozzle work on a planing hull?". To take this to the extreme, the blades would have to be in a cage, like an electric fan. That would introduce horrible problems, the inflow would become turbulent, not laminar, and the outflow would push on the cage causing a large drop in efficiency. The behavior of incompressible fluids, e.g water, is different from that of compressible fluids, e.g. air. Looks like we're headed to having jet drives, which are completely enclosed, as lower units.

jimh posted 04-16-2010 09:24 AM ET (US)     Profile for jimh  Send Email to jimh     
[I removed several comments about litigation for injuries. Please--let's keep this discussion's focus on performance, not litigation.]
K Albus posted 04-16-2010 01:42 PM ET (US)     Profile for K Albus  Send Email to K Albus     
There are propeller guards currently on the market which claim to increase performance. See: http://propguard.net/how.html
JMARTIN posted 04-16-2010 01:57 PM ET (US)     Profile for JMARTIN  Send Email to JMARTIN     
I wonder how much stuff would be hanging of one of those after a trip through Puget Sound? Anything that improves fuel economy is of interest to me.

John

pcrussell50 posted 04-16-2010 02:14 PM ET (US)     Profile for pcrussell50  Send Email to pcrussell50     
quote:
There are propeller guards currently on the market which claim to increase performance. See: http://propguard.net/how.html

There are also things like this that make similarly believable claims.

http://www.asseenontvguys.com/index.asp?PageAction=VIEWPROD&ProdID=706

-Peter

contender posted 04-17-2010 12:14 AM ET (US)     Profile for contender  Send Email to contender     
K Albus: Did you read the advertising, States the boat can not be under powered, overpowered, type of hull and design will change/effect the performance of the boat. Kinda a lot of holes in the statement to protect the performance of the prop guard.
I believe that performance of outboard/props were design to perform without the incumbency of a prop guard. The only safe outboard/boat would be a jet drive, which has no prop at all.
Hoosier posted 04-17-2010 12:40 AM ET (US)     Profile for Hoosier  Send Email to Hoosier     
This quote is from the Measurements page of the Prop Guard website:

Prop Guards will fit all Manufacturers Outboards and Stern Drives. Note: All hp's with Big Foot & High Thrust applications require next size up.

ALL APPLICATIONS of the 13", 14", and 16" Prop Guards are for PONTOON AND DECK BOATS, and any other application that the vessel does not exceed 25 mph.

Looks like this solution won't work in our world, unless all you do is troll.

K Albus posted 04-17-2010 01:09 AM ET (US)     Profile for K Albus  Send Email to K Albus     
All I said is that they claim it improves performance. I didn't say I believed it.
jimh posted 04-17-2010 10:05 AM ET (US)     Profile for jimh  Send Email to jimh     
As a general rule, you could say that manufacturers of outboard motors are very competitive and are looking for any possible advantage in selling their motors. If there were a way to employ a propeller which caused an improvement in performance of the outboard motor, such an improvement would be of great interest to outboard motor manufacturers. If the cost of a new method of employing a propeller on an outboard motor for better propulsion was only incremental, you can be certain that the method would be very attractive and would likely be in use, if not as a standard method, at least as an optional method at higher price.

If we look at current optional methods for propellers and propulsion improvements, we see that even methods that add $500 to the price are very popular. For example, many outboard buyers will pay $600 for a propeller (made from stainless steel) that provides better propulsion compared to a $100 propeller (made from aluminum). Added expense like this is routinely borne by buyers of outboard motors who are seeking more performance. Based on this example, it is reasonable to say that for many outboard motor buyers a price increase of $500 is not too much to pay for a marginal improvement in performance.

Several of the products mentioned so far appear to cost $500 or less. If these products actually produced increased performance, they should be very popular. In my experience, they are not in wide use. The most reasonable conclusion is their lack of wide use is due to a lack of improvement in performance.

If a ducted propeller would result in improved performance, and if the cost were approximately $500, I would expect to see as many of these devices in use as I see stainless steel propeller in use on outboard motors. However, in my experience, I see almost universal use of stainless steel propellers and literally zero use of ducted propellers. My conclusion is that either the ducted propeller does not improve performance, the ducted propeller is much more than $500, or there is a completely inefficient market with regard to improving boat performance.

pcrussell50 posted 04-17-2010 02:20 PM ET (US)     Profile for pcrussell50  Send Email to pcrussell50     
Jim,

While that was a faboulous writeup, with an irrefutable conclusion, it's still a wee bit exclusionary of people who lack the inclination toward critical thought and reason. I can show you, for example, a very damaging instance in which at least 12 people, through rhetorical sleight of hand, were not able to grasp the concept you present.

-Peter

jimh posted 04-17-2010 04:01 PM ET (US)     Profile for jimh  Send Email to jimh     
Peter--As a general rule the CONTINUOUSWAVE website tends to exclude people who lack critical thought and reasoning. For those people who lack critical thinking and reasonsing, there are many other websites for them to visit, to read, and even to publish their writing. Here we try to stick to the laws of Phyiscs and well-known or proven relationships in modern life. So your proposal that my reply is exclusionary of people who lack critical thought is, to my way of thinking, just about business as usual here on CONTINUOUSWAVE.
Florin posted 04-30-2010 01:42 AM ET (US)     Profile for Florin  Send Email to Florin     
If the "tube" around the propeller is designed to have low drag, and if it is dimensioned properly versus the circumference made by the tips of the propeller, it should increase the force given by the propeller.

All the fluid which goes radial due to centrifugal force will be forced along the axis of movement. Also, it will reduce the turbulence around the tips of the propeller.

jimh posted 04-30-2010 02:13 AM ET (US)     Profile for jimh  Send Email to jimh     
I do not profess to be a naval architect, but I have read on the topic to some depth of understanding beyond the bass-boat fisherman level, if I might characterize it with that metaphor. My understanding of boat propulsion for lightweight planing craft like our classic Boston Whaler boats is that when the boat has transitioned onto hydroplane, a large source of drag that must be overcome to increase boat speed is the drag of the outboard motor gear case and the propeller itself. As a corollary, we hear a great deal of talk about reducing the volume or cross-section of the gear case that is immersed in the water by raising the engine mounting height. Anecdotal reports tell of improvements in boat speed of 2 to 3-MPH simply from reducing the amount of immersed gear case from raising the engine 0.75 to 1.5-inch. From this it is reasonable to conclude that at planing speeds the drag from the gear case is a significant factor in performance.

If a duct or tunnel were created around the propeller, the cross section of the immersed gear case would be significantly increased. If an improvement in performance were to be realized from this approach to propeller deployment, the improvement from the greater efficiency of the ducted propeller would have to overcome the added drag from the cross section increase due to the duct.

number9 posted 05-01-2010 03:39 AM ET (US)     Profile for number9  Send Email to number9     
Depending upon the design of a ducted propeller, the increase of frontal cross sectional area and drag shouldn't degrade utility significantly. Certainly it won't increase performance, if so motor manufacturers would have incorporated those designs into their products. Many would even be against a "safer" [design] if it improved fuel efficiency by 10-percent but reduced performance by 10-percent.
pcrussell50 posted 05-01-2010 03:57 AM ET (US)     Profile for pcrussell50  Send Email to pcrussell50     
quote:
If the "tube" around the propeller is designed to have low drag, and if it is dimensioned properly versus the circumference made by the tips of the propeller, it should increase the force given by the propeller.

My coverage is by no means complete, but no ducted fan application I know of is more efficient than un-ducted fans. Remember "propfans"? They did NOT fail because they were less efficient than turbofans anymore than Beta failed because it was inferior to VHS.

If this stupidity becomes law, "fastboating" will become a little slower, or a little more expensive, and in reality, probably both.

-Peter

pcrussell50 posted 05-01-2010 12:10 PM ET (US)     Profile for pcrussell50  Send Email to pcrussell50     
I really should correct my last sentence. It should read:

If this stupidity becomes law, utility boating, like we do with out Whalers, will become a little more expensive, and a little slower. "Fastboating" will become a lot more expensive and a lot slower.

-Peter

Hoosier posted 05-01-2010 12:53 PM ET (US)     Profile for Hoosier  Send Email to Hoosier     
This is an interesting thread about this subject, contributor include naval architect types.

http://www.boatdesign.net/forums/boat-design/ shrouded-propeller-v-s-nonshrouded-opeller-24756-3.html

One big question seems to be what is a shroud, a ducted propeller, and a pump jet. How are they different and how do they perform?

number9 posted 05-01-2010 01:54 PM ET (US)     Profile for number9  Send Email to number9     
quote:
If this stupidity becomes law, utility boating, like we do with out Whalers, will become a little more expensive, and a little slower. "Fastboating" will become a lot more expensive and a lot slower.

Have not heard of any impending legislation and it's not likely we'll see any soon. If the recent judgment is ultimately upheld and more suits follow there may be an incentive for the OB and OD makers to incorporate them into their products. There has to be financial incentive to justify research, design and production changes. I think we all agree there would be some speed loss but probably significantly less than we have been lead to believe. Remember these drives have remained basically the same since day one and most of the money has been spent increasing powerhead output.
contender posted 05-01-2010 02:10 PM ET (US)     Profile for contender  Send Email to contender     
Number9: The current government (everywhere) is out of control. It's coming you wait and see, look what just happen somewhere in Ca. No More Happy Meals, So now the government is telling the people what they can eat, think about that one....
pcrussell50 posted 05-01-2010 06:22 PM ET (US)     Profile for pcrussell50  Send Email to pcrussell50     
'Niner,
You present a probable timeline based on logic and reason. However, that the stench of the plaintiff's case was not enough to have it immediately banished from court, is proof enough that logic and reason are not the governing factors at play here. The industry is in the clinging to a thread. They can no longer count on a "fair and right", liability scenario on which to base the design of future products. If they're frightened enough, I could almost see them actively curtailing the lives of their current, in-service product line either by cutting off the supply of repair parts, or implementing "scrappage" programs with rebates for "safer" replacements, or both. Who knows exactly how the wounded and scared, "animal" will respond?

What if getting an enclosed propeller/impeller system back to say, 85% efficiency would require doubling the cost of an outboard? But what if getting it to 70% of pure propeller efficiency only increases the cost by 50%?
Which path would the outboard manufacturer be more likely to follow? I don't know... these are rhetorical questions because nobody knows which direction the industry will take when confronted with such a choice.

I don't see any way the outcome will be a win for boaters save for some as-yet-unimagined breakthroughs in fluid dydnamics... breakthroughs that have thus far, eluded the aerospace industry. As a footnote, even if such a breakthrough does take place, if the research and technology it takes to implement it follows aerospace processes, a mere doubling of the cost of an outboard will be a pipe dream.

-Peter

appdiver posted 05-06-2010 01:22 PM ET (US)     Profile for appdiver  Send Email to appdiver     
The motor/lower unit you reference would be spelled: D-U-R-A-J-E-T (Durajet). Do an online search, which will include "actorlando.com" amd "Premiermarine.com"...this is a tested and proven technology.
pcrussell50 posted 05-06-2010 02:48 PM ET (US)     Profile for pcrussell50  Send Email to pcrussell50     
Yes. I know them well. First, their "technology" goes all the way back to the 80's. And have you seen their web site? Their own web site tells it all... if you are willing to run your motor at 5500 rpm on a non-planing hull, under a load that keeps your speed down BELOW 20mph, the durajet will give you an advantage... of 8/10 of a mph. Whoopee.

For the doubting Thomases:
http://www.premiermarine.us/durajet-propeller.php

They presented good, scientific testing to get their data above, but then they toss this turd into the punch bow:

quote:
On fast-planing performance hulls, users can expect a 5 to 10 percent decrease in speeds when compared to a similar prop engine.

Why make a guess like that? The difference between a 5% loss and a 10% loss is 100%. Quite a spread unless it was based purely on conjecture. It is likely that the speed loss was based on conjecture, because scientific testing was not actually done on planing hulls... which in turn was probably because there was no point in doing so, when your objective is to sell units and you already knew the results would not be favorable to you. Look, the Durajet looks like a quality, well-engineered unit. The engineers were probably not stupid. They know darned good and well, this is a sub-optimal solution for planing hulls. And I'll bet the efficiency drop increases non-linearly with speed. What do you want to bet that the speed penalty is AT LEAST 10% on your typical 40mph Whaler? Oh, and it's $1700 EXTRA, with no choice in "propeller" pitch.

If you are somebody who thinks that even in a free society, nobody ought to enjoy going fast in a boat, disregard the following:
I wonder what the penalty is on a 70mph boat? I wonder if it's even possible to get one up to 70mph without exceeding an engineering limitation? I wonder whether it's possible to get to 70mph at all... even if you are willing to exceed an engineering limitation? And 70mph isn't even fast anymore. It's basic bass boat speed. Real fastboaters don't come alive until the mid-80's.

-Peter

cooper1958nc posted 05-07-2010 06:25 PM ET (US)     Profile for cooper1958nc  Send Email to cooper1958nc     
A properly ducted propeller will be more efficient than an unducted propeller. The reason is the "end plate effect." This effect, demonstrated on aircraft with "winglets", improves efficiency by limiting wingtip vortices. The effect is to add effective span while keeping chord constant, which improves aspect ratio. Long, slender wings are more efficient because less energy is lost in wingtip vortices. WIngs with end plates act like longer, slenderer wings. Propellers are rotating wings and have the same problems with energy lost off the end of the wing through spanwise flow. Ducting the propeller decreases these parasitic losses. To work best, the duct has to be very close to the tips.

Note I have said nothing about the duct itself. Of course, in a submerged propeller, the duct contributes, probably very significantly, to parasitic drag.

The net effect? Probably some increase in overall efficiency at slow speed, a negative as speed increases.

But of course every American has the birthright to run her unducted propeller as fast as she wants, through whatever obstacles, marine life, or recreating children may be present "in the way".

pcrussell50 posted 05-07-2010 11:51 PM ET (US)     Profile for pcrussell50  Send Email to pcrussell50     
quote:
Of course, in a submerged propeller, the duct contributes, probably very significantly, to parasitic drag.

To say the least. Bolding mine, to indicate full agreement.

quote:
But of course every American has the birthright to run her unducted propeller as fast as she wants, through whatever obstacles, marine life, or recreating children may be present "in the way

The bolding is the part I disagree with, and have no part in myself. Nor does anyone I know, for that matter. The part before that is pretty much true.

-Peter

number9 posted 05-08-2010 05:46 AM ET (US)     Profile for number9  Send Email to number9     
As said before doubt we will see prop guards legislated or voluntarily designed and produced by the manufacturers any time soon, likely not within many of our life times, if ever.

The argument of additional cost was brought up. A guard/duct incorporated into the gearcase housing casting would not add much to the cost of a motor.

We seem to agree any prop guard design is going to increase drag and cause lost performance particularly at higher speeds. Percentages of efficiency loss are easy to throw out there but they are just guesses. Until a organization with deep pockets such as Mercury Marine puts a team of designers/engineers on a project to produce some prototypes and do testing the numbers will remain elusive. One thought that comes to mind is that some of the drag may be able to be reduced by ducting some of the exhaust through the guard?

Enjoy your weekend and be safe.


pcrussell50 posted 05-08-2010 03:28 PM ET (US)     Profile for pcrussell50  Send Email to pcrussell50     
quote:
We seem to agree any prop guard design is going to increase drag and cause lost performance particularly at higher speeds. Percentages of efficiency loss are easy to throw out there but they are just guesses.

Re inefficiency, most of us don't have wind tunnels or supercomputers to perform CFD analysis, (Jim, CFD = computational fluid dynamics). Nonetheless, reliable anecdotes abound. The disastrously inefficient turd that's available now, adds $1700 _minimum_, to the cost of a 50-60hp class of outboard, and that's for the "civilianized" version. I wonder how much more the more complex-looing, military/commercial/lifeguard version costs? Don't you? double-to-triple the cost would not surprise me one bit.

As for Mercury's deep pockets finding a better solution? Maybe. Greater efficiency in ducted fans has thus far eluded Boeing and Airbus.* I've said it before and I'll say it again. Gains in ducted fan efficiency will be incrementally small, and cost increases will be disastrously non-linear.

*In fact, with the fuel situation what is is today, the major jet engine manufacturers are having to revisit the fan section of their turbofan engines. GE and Rolls Royce are desperate to drop the ducted fan altogether and are re-opening research into un-ducted fans. For balance, Pratt and Whitney are trying to develop a gear-driven fan section, knowing that it has no chance of being more efficient that an un-ducted fan. PW is gambling that fuel prices will remain stable and that the public will view un-ducted fans as "propeller planes"** and thus dislike them. It's almost a cruel joke to consider that li'l 'ol Mercury will be able to make something that is not disastrously inefficient at "Whaler-like-speeds", around 40mph... to say nothing of higher speeds.

**It was public perception of the propeller-plane-like cabin noise and vibration that doomed the propfans at the end on the last energy crisis in the 70's.

-Peter

PGIC posted 03-29-2012 09:20 AM ET (US)     Profile for PGIC  Send Email to PGIC     
The American Boat and Yacht Council (ABYC) and CED Investigative Technologies were contracted by USCG to produce a test protocol for propeller guards. They recently released a draft of the test protocol for public comment. The deadline to comment is April 11, 2012.

We supply the draft protocol and instruction on how to comment at:

http://www.propellersafety.com/4574/test-propeller-guards/propeller-guard-test-protocol-rough-draft/

Please note ABYC and CED are requesting constructive comments on their test protocol, not comments on the issue in general.

We encourage all interested parties to respond.

gary polson
Propeller Guard Information Center

Tom W Clark posted 03-29-2012 09:27 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
http://www.propellersafety.com/4574/test-propeller-guards/ propeller-guard-test-protocol-rough-draft/
Tom W Clark posted 03-29-2012 09:43 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
The document itself:

http://www.propellersafety.com/wordpress/wp-content/uploads/ CED-effectiveness-propeller-guards.pdf

Teak Oil posted 03-29-2012 10:48 AM ET (US)     Profile for Teak Oil  Send Email to Teak Oil     
I would be strongly against a mandatory guard on propellers that would decrease the efficiency and performance of propellers.

A VERY high number of propeller related accidents are due to a lack of knowledge of the operation of a boat on the operators part. I would agree to mandatory licensing to operate a boat before I would want more "safety" devices designed to "idiot proof" boats from ignorant operators.

I know it has not been stated that the Coast Guard would intend to make such a device mandatory, but given the present tendency for this country to make mandatory rules to protect everyone (smoking bans, seat belts, etc) I can easily see this heading in that direction also

davej14 posted 03-29-2012 11:32 AM ET (US)     Profile for davej14  Send Email to davej14     
There are always unintended consequences to consider. Assume that the boating world must conform to some bureaucratic nonsense imposed by non participants without a clue about the technical details of what they are legislating. Not withstanding the lower efficiencies, how many injuries would be caused by operators trying to clear debris from these shrouds which heretofore did not exist ? How many injuries would be caused by carelessness because the operators and guests would have a lower respect for the inherent danger of the prop ?

This effort is all just political BS driven by fear of law suits and by uneducated well intentioned legislators.

DVollrath posted 03-29-2012 11:56 AM ET (US)     Profile for DVollrath  Send Email to DVollrath     
Fears of future changes aside, it appears from the text of the document that the intent is to provide consumers with sufficient information to choose a product if they so desire:

quote:

This matrix is not intended to be a design test standard, a law, or a regulation. The matrix is intended for use by manufacturers of propeller guard devices, other testing entities, and the consumer to evaluate guarding products in a way that allows comparison with other products on an "apples-to-apples" basis.

It is not clear to me that the document contains any real test results, but I find the table on page 16 (Figure 3) to be very interesting if in fact it is based on some aggregate real results. It would appear that for the most part you are better off with no guard than with the "ring" style.

As much as I understand it, I like their testing methodology

Dennis

pcrussell50 posted 03-29-2012 12:43 PM ET (US)     Profile for pcrussell50  Send Email to pcrussell50     
What utter coincidence--I was reading through propellersafety.com's web site last night and considering resurrecting this old thread, when someone beat me to it.

The thing that struck me right between the eyes was the utter lack of any kind of physical guarding device that is not so inefficient that it would change the very nature of planing hull, recreational boating if forced upon the boating public. This is really no surprise to me, as I have the mathematical and physical sciences background to understand why--not that you need it.

Thy had a list of manufacturers of prop guard-type systems. Interesting observations:
-about half of them were Australian
-almost all of them had very low, (as in lucky if you can plane) speed limits
-the Austrailan web sites tended to be very up-front about the fact that ring guards are not intended for planing hulls, sometimes using bold print to alert the shopper. "this device intended for trolling use only" and such.
-the American web sites that sell ring guards were way more slippery on the subject, either not mentioning that their product will wreck your boating expectations (if you intend to plane), or hiding it deep in a stack of links.
-I couldn't find anything about that turd, DuraJet, which at least looked like it was the best of breed among guard-type solutions. They were on the right track as to a "proper" implementation.

The scariest thing I read:
I read propellersafety.com's commentary on the Mercury propeller case (Jacob Brochtrup v. Mercury Marine and Sea Ray), that we went rounds over here on CWW a couple of years ago. It was yet another, "driver backs over his swimmer", accident. Basically according to propellersafety.com's coverage of the subject, the jury found Mercury found negligent, and lost the case, because they resisted and failed to use this very device right here, (taken from propellersafety.com's web site article on the Mercury case:

http://www.propellersafety.com/wordpress/wp-content/uploads/ Taylor-3PO-propeller-guard-rear-view.jpg

A jury found Mercury was negligent because they didn't install one of these? God help us.

To ps.com's credit, a very large portion of the briefs on their site included other concepts for propeller safety than guards, including education programs on the dangers of propellers.

Further, to their credit, they also list the things, (some grudging tone), that are drawbacks of guard-type solutions.

here:
http://www.propellersafety.com/propeller-guard-objections/

and here:

http://www.propellersafety.com/propeller-guard-design-trade-offs/

Both worth reading.

-Peter

PGIC posted 03-29-2012 02:59 PM ET (US)     Profile for PGIC  Send Email to PGIC     
Thanks pcrussell50 for the honest review of our site. Some readers tend to overlook our content and instantly classify us as radicals trying to put guards on every boat in the universe. They fail to see the many other approaches to propeller safety and our recognition of some of the problems of conventional propeller guards.

Its refreshing to hear from someone who actually read some of our content before they started writing about us.

Have a nice day

gary polson
Propeller Guard Information Center

pcrussell50 posted 03-29-2012 03:14 PM ET (US)     Profile for pcrussell50  Send Email to pcrussell50     
Great site, Gary. Glad to have your here at CWW.

It is good to have a place for "one-stop-shopping" on the very broad-based, propeller safety issue, which encompasses everything from news coverage of accidents and liability trial proceedings, to available technology, and the latest happenings with such. That is a lot of stuff to stay abreast of, and having it all in one place is a golden resource.

Even though I am against mandatory use of prop guards, (as they exist today), I will continue to visit your site because of the wealth of information there at my fingertips.

Stay as objective as you are, (a challenge for all of us), and I will be visiting often, and linking to it as appropriate.

-Peter

pcrussell50 posted 03-29-2012 03:17 PM ET (US)     Profile for pcrussell50  Send Email to pcrussell50     
BTW, I like the Wordpress core of the site, too. Slim, fast, and no-nonsense. If you get tempted to go all fancy schmancy, (technical term), know that my vote says, stay with Wordpress.

-Peter

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