I saw something weird on an outdrive, what was it for?

[adamjr]

Re: I saw something weird on an outdrive, what was it for?

Good grief. Cold water being constantly sprayed on the upper gear housing, cools the aluminum housing. Heat goes to cold. (Physics) so the heat from the gear lube is cooled by the cooler aluminum housing that is being cooled by the lake/ocean water being sprayed on it.

Kind of works like putting cold water in your radiator when the engine is hot. Ever notice how the engine cools down.

Actually my background prior to getting into office equipment was auto mechanics. Pouring cold water into a hot radiator/engine has a nasty habit of cracking blocks due to rapid contraction.

Thanks for the replies. If I happen to see that boat again I'll try and get a picture.

 

[Don S]

Re: I saw something weird on an outdrive, what was it for?

Actually my background prior to getting into office equipment was auto mechanics. Pouring cold water into a hot radiator/engine has a nasty habit of cracking blocks due to rapid contraction.

Thanks for the replies. If I happen to see that boat again I'll try and get a picture.

I said that as an example, meaning that it would cool it down. Not that you should do it while your engine was hot. give me a break, I didn't suggest it should be done (not that some haven't tried it).
Besides, the drive shower works while you are moving, it doesn't have a thermostat that opens up the flow when the drive gets hot. It's always on, so it's a constant cooling.

 

[QC]

Re: I saw something weird on an outdrive, what was it for?

it doesn't have a thermostat that opens up

I do like simple things. It does have more cooling as load (speed) goes up . . .

 

[bruceb58]

Re: I saw something weird on an outdrive, what was it for?

So if a drive shower is such a good thing how come everyone doesn't do it. Don, do you have one on your boat?

Jason, if you don't agree with us, 45auto is going to be in here in a second and this whole thread is going to be full of diagrams showing how wrong you are.

 

[Alpheus]

Re: I saw something weird on an outdrive, what was it for?

 

[Don S]

Re: I saw something weird on an outdrive, what was it for?

So if a drive shower is such a good thing how come everyone doesn't do it. Don, do you have one on your boat?

I have an outboard on my boat now :redface: So no, I don't have one.

And I don't think everyone needs one either.
Boats that run constant LONG (50+ miles one way) day in and day out like some charter boats that I had to deal with in AK are the ones that need it. A normal usage like most people do for recreational boating is completely different.
If you change your gear lube yearly and it looks new or slightly darker, then you don't need it. But if you drain your gear lube after a lot of hard use like I described above, and the burned smell drives people out of the neighborhood a block away, then yeah, the drive shower will help.

 

[JustJason]

Re: I saw something weird on an outdrive, what was it for?

I have an outboard on my boat now So no, I don't have one.

The I/O forum moderator runs an OB.... hehe.. Classic

Just bustin yer gearsets Don.

 

[Don S]

Re: I saw something weird on an outdrive, what was it for?

The I/O forum moderator runs an OB.... hehe.. Classic

Just kidding, I have a Volvo 5.7GXi-E with a DP outdrive on my boat.

PS: That thing on the back is a disguise. Don't want any one to know what I am really running.

 

[HT32BSX115]

Re: I saw something weird on an outdrive, what was it for?

EVERYBODY WANTS a BIG Johnson!!!!

 

[JustJason]

Re: I saw something weird on an outdrive, what was it for?

Rick your going to give people Johnson envy with photo's like that!!

 

[mcleaves]

Re: I saw something weird on an outdrive, what was it for?

You guys suck.. I had better things to do with my winter than fabricate and install a drive shower!!

Great.. Just great!

M

 

[Fun Times]

Re: I saw something weird on an outdrive, what was it for?

Heat does not rise..hot air maybe but not heat in of itself.

It must be that the heat doesn't transfer through the joint.

Has anyone actually hung their a-$$ over the transom with an IR gauge to measure the top of the drive after driving for an hour?[/QUOTE]Yes some guy's have done that in the past, You just need a trusting friend to hold you're legs good enough

But now a day's they have drive temp gauges for this, And a lot of the big [HP] guy's use them. http://www.keitheickert.com/searchresult.aspx?CategoryID=579

 

[Fun Times]

Re: I saw something weird on an outdrive, what was it for?

Forgive my crude drawing and sorry it's not to scale.

The tube was forward of the prop so I don't think it would have caused a rooster tail. I certainly could be wrong.

Just to throw a wrench in all of this, There is a chance he could have seen a real race boat with A different style sterndrive, Like a #6 speed master, ect, That would be in need of prop aerator tubes, And it does kind of looks like the drawing he did a little bit. Here is a link of what i'm talking about Just to make sure, But my guess would also be a drive shower also.

http://teaguecustommarine.com//store/index.php?main_page=product_info&cPath=203_345&products_id=1020

A R E A T O R S

--------------------------------------------------------------------------------

TEAGUE CUSTOM MARINE'S: Custom prop aerator kit is designed to allow air to the propeller which helps large boats w/ radical engine to come onto plane easier. In pleasure applications, the aerators take the load off the props when maneuvering around docks, and help to prevent engine stalling when engines are shifter in/out of gear. In race conditions, aerators improve throttle response coming out of corners or after hitting down on that big wave by instantly relieving the propellers!

 

[PeterMcG]

Re: I saw something weird on an outdrive, what was it for?

I hate to say it to you Bruce, But heat rises..... it doesn't sink

I stand by my original statement.... Heat rises.

Well, this sucks.
I am gonna have to replace all of my Thermodynamics, Heat Transfer and Physical Chemistry texts -- if what you say is true, then the texts are seriously in need of updating.

I wonder if this change has been accounted for in the F.E. exam and the P.E. exam?
With this fundamental change in our understanding of thermodynamics, a lot of things get altered...

 

[Fun Times]

Re: I saw something weird on an outdrive, what was it for?

]Just kidding, I have a Volvo 5.7GXi-E with a DP outdrive on my boat.[/B]

PS: That thing on the back is a disguise. Don't want any one to know what I am really running.

And just when I thought you where going to tell us all you were hiding the new vaser engine set up from mercruiser under the floor board for extra power

 

[Philster]

Re: I saw something weird on an outdrive, what was it for?

Heat will transfer from the internals to the casing rapidly when the casing is cooled by water, because heat is being transferred from the casing to the water.

Internal heat > casing > shower water > sea

Folks, the bottom of the drive is in the darn water. I am pretty sure that helps keep it cooler than the top.

Heat radiates.

 

[Fishermark]

Re: I saw something weird on an outdrive, what was it for?

Just to throw a wrench in all of this, There is a chance he could have seen a real race boat with A different style sterndrive, Like a #6 speed master, ect, That would be in need of prop aerator tubes, And it does kind of looks like the drawing

You guys are too funny! All this talk of physics... and heat rising or falling... and ir guns.... etc.

Then on top of all that - Don S with an OMC product!!


Back to the original poster, I would say boat teck has found the answer. The site he posts a link to has a product exactly as described by the original poster. I've never heard of such a thing, but then again I am not an offshore racer.

Now, if we could just start a thread on the value of aerators......

 

[HT32BSX115]

Re: I saw something weird on an outdrive, what was it for?

I stand by my original statement.... Heat rises.

Gawd I hate to jump in on this stuff....



HEAT doesn't "rise".

Heat is conducted though a medium. ( a medium can be a metal, liquid or a gas)

If the medium is a gas, (or combustion gases above a flame) it (the hot GAS) will only rise because it is lighter than the surrounding air. If it's a liquid the heated liquid will only only "rise" from convection (air and liquids will also conduct heat otherwise our boats, cars, air cooled lawnmower, etc would overheat....but air is not as good a medium as liquids or certain metals......Stainless steel by the way is a terrible conductor of heat)


In a stern drive there is *some* oil flow top to bottom/bottom to top from gear rotation. (which is why you need to rebuild the whole drive when you get damage in a "lower" or an "upper") AND there's a LOT of heat transfer top to bottom when you work it hard.

Under normal operation, The top is cooled from heat transfer to the bottom via some oil flow and metal-to-metal heat transfer.

When you work them hard however, (read: use more power on the drive than was it was designed for) you cannot transfer enough heat from top to bottom via the above process so some people have come up with a way to spray water (a heat transfer medium) on the exposed "upper" part of the drive to help cool the drive.


If you have a drive that is powered as it came from the manufacturer, you probably don't need a shower.....(if it's been a couple of days....since your last shower........TAKE A SHOWER!!!.....everyone around you will thank you for it!!!!!)



Cheers,


Rick

 

[QC]

Re: I saw something weird on an outdrive, what was it for?

I think boat teck is on to something . . .

 

[Knightgang]

Re: I saw something weird on an outdrive, what was it for?

So what is the value of an aerator on a Go Fast Outdrive, or any outdrive for that matter,,,