Jet Drive

[William]

Does anyone know much about the jet drives the PBR boats used?
Diagrams pictures models?

[Jerry M. Hammel]

                                                YES

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[William]

Clearly Jerry you're man of few words.
I'll rephrase my question. Does anyone have diagrams pictures or
models that they're willing to share and post?

Thanks
Bill

On Nov 5, 4:00 am, "Jerry M. Hammel" <jerry.ham...@browardschools.com>
wrote:

[Den]

I have NO idea why Jerry M. Hammel even bothered to respond with no
information. Some people are not worth responding to.
Engine (made by): "Detroit Allison Corporation" or "GM"
Quantity: 2
Engine Power: 250 HP
Engine Type: 6v-53 Diesel
Engine Volume: 4300 cubic cm or 318 cubic inch
Pump (made by): "Jacuzzi Corporation"
Pump type: Jet propulsion
Quantity: 2
Pump Power: 6000 Gallons per minute
Discharge Nozzle: 6" in diameter
This is one of the engines
http://www.odcloth.com/PBR7329/6v53.jpg
This is a pair of Dowty Pumps, the Jacuzzi Pumps are RARE
http://www.odcloth.com/PBR7329/Dowty1.jpg
http://www.odcloth.com/PBR7329/Dowty2.jpg
This guy has, and is doing some serious chandlery.
http://www.g503.com/forums/viewtopic.php?t=79640&sid=70e7b74923d4873557b9d4c99d2b9dd5
I do not have any other information, but feel the need to help you
research your question. Learn to do your own searches. Like searching
this group only brings up one hit. Poking search groups brings up
about 1,520 for PBR boats. That should keep you busy.
I use dogpile at www.dogpile.com It uses 4 search engines, so really
collects bunches of hits. Yes lots of them are garbage, but you will
be able to figure out which ones may be meaningful.
By inserting 'PBR jet drives' I got 3 pages, about half worth checking
out. of course you can quickly skip eBay, BizRate, and shopping yahoo.
The Wiki site might be interesting, but keep in mind it is built buy
people like yourself and I, who think we know what we are talking
about.
Some of the military sites have missing photographs, hmmmm
interesting. (A Big Brother thing?) Anyway the main idea is ask here,
and someone usually has an intelligent pointer / response. Then do
your own searches, and see what is out there.
Have fun
Den Uniflite 48YF densnet.com
I am NOT regulated by Florida law . .?

[tomdepot]

William,

Over the years watching this site, I have seen many people ask about
the PBR jet drives. In your case, does this mean that you are
intending to restore/recreate one? I own a 1968 31' express which is
supposedly the same hull as the PBR and it runs great with the two
four cylinder diesels I have in it. What I am really curious about
is, do you have any direct experience in the performance of the old
jet drive setups? Would they handle like jet ski's, in that you only
have steering at higher rpms and no reverse? I would worry that its
performance would be so inferior to a modern setup that you might
regret the project, although I realize for a history/military buff
it's the originality that matters most. I am not trying to argue
against such a project, just curious.

Another driving force behind my question is that a friend of mine told
me recently that the old Detroits were so noisy and vibration prone
that he would never buy a boat with one. This is something else I
have never personally experienced, but curious if you have.

One thing I can say, I would like to not have to worry about submerged
obstructions. I passed a floating log going out the channel the other
day and couldn't help but wonder what might have happened had I run
over it instead of just by it. You can't see the damn things until
you are right on them.

Good luck,
Tom in Floirda

[William]

Den WOW! This is great information! That G503.com looks interesting.
Are you building that boat? Thank you.

To kinda answer yours and Toms questions,
I have a 28' Express that needs a fair amount of work. I have it out
of the water and recently pulled one of my twin 318's that is frozen
up. My nephew is a machinist for a company that manufactures custom
irrigation and well pumps. I live on the Sacramento River where there
are lots of hidden treasures for your props to play with. It also
varies in depth in some places quite drastically. He I started talking
about converting my Uniflite to jet drives. I'm not sure that this is
even a remotely feasible idea but I wanted to look into it. My folks
and I looked at a 65' La Conner that was built by a Microsoft exec out
of WA. It was jet driven for shallow water ways up there. What a neat
boat.
Let's pretend that this is a project that makes it off the ground. I
would use my 318's (rebuilt) wit a possible propane conversion and run
some type of jet drive system. I would run be able to run in 2' of
water?? Also without concern of props hitting debris.

I have a lot of investigating to do. Thoughts, comments, and ideas
welcome.

[kinnardw]

Fisherman have been using them on uniflites in alaska for the years! Works great but fuel increases by about a third.

[The entire original message is not included]

[waterguy]

On Nov 6, 2:06 pm, kinnardw <kinna...@mtaonline.net> wrote:

> Den WOW! This is great information! That G503.com looks interesting.

* * *

> Let's pretend that this is a project that makes it off the ground. I
> would use my 318's (rebuilt) wit a possible propane conversion and run
> some type of jet drive system. I would run be able to run in 2' of

William:

Don't take me the wrong way or anything, but I'm glad you're in the
Sacramento Delta and not gonna be mooring anywhere near me. Anybody
else here see a problem with a couple of hundreds of gallons of
liquefied petroleum gas in steel tanks in the enclosed spaces of a
boat? Anyone?

Seriously, what are you thinking? Why on earth would you want to do a
propane conversion on a boat? There's nowhere to fuel it, and I
seriously doubt that any delivery truck is going to be willing to run
a hose down a dock. To say nothing of the fact that the minute your
marina finds out you're propane-fueled, or sees a propane truck
unreeling a hose on the dock, you're going to be out on your keister.

It can't be for better mileage; in vehicles propane/LPG fuel results
in lower economy (propane has only about 73% of the heat energy of an
equivalent volume of gasoline). The only reason I can think of is due
to propane not having highway taxes. I don't know about California,
but in Washington, if you buy gas for a boat you can submit your
receipt(s) for up to 6 months with a form requesting a refund of the
highway taxes, so at least for us, that's not a reason. And once you
back the taxes out, the difference in price is made up by the lower
fuel economy.

Frankly, if you're thinking of going propane to save 30 or 40 cents a
gallon, may I respectfully submit that boating is not a hobby you want
to get into? Please don't take me wrong, but you're too cheap. If
your boat goes 1 nautical mile per gallon of gasoline (your 31 should
do at least 1.5 or 2 nmpg at planing speed, much more at hull
(trawler) speed. But assume 1 nautical mile per gallon. It would
take you around 25,000 gallons of gasoline to circle the Earth at the
equator. Saving 30 cents a gallon would result in a net savings of
$7,500 on a complete circumnavigation. You'll never take your boat
that far in a lifetime of cruising the Delta, so your savings will be
proportionately smaller.

[I just wrote several paragraphs of more-or-less scientific reasons
propane is a bad idea, but I decided to keep this short, so I deleted
them]

I can't even begin to state clearly how bad an idea I think this is.
Certainly, propane may have a limited place on a boat: cooking and
heating. But as the principal means of fuel? Never. Ever. There's
a reason that ocean-going LPG tanker docks are dozens of miles from
anything else.

Another thing: the Coast Guard has rigid requirements about propane
tanks: They must be above-decks, not connected to living spaces, not
open to engine spaces and if enclosed in a locker, the locker must be
vented overboard. I can't think of where you're going to put propane
tanks on your boat that will meet these requirements; and if you
ignore them and get boarded, your boat will be immediately impounded.

Oh, this is so not a good idea.

And it just occurred to me what an insurance underwriter would have to
say about the whole idea . . .

However, it also occurs to me that there might be one reason: you'll
have the first Uniflite to reach Alpha Centauri.

[William]

Well there goes propane!

The reason behind the idea was not finacial, but thanks for your
concern. My ideas for propane were two fold. One it's almost a zero
emission fuel. Two it's primarily a domestic product. If I could do my
little part to decrease dependency on foreign oil and cut down on
emissions all while enjoying my boat well yeehaa!

[Den]

>That G503.com looks interesting.
> Are you building that boat? Thank you.

Nope. Not working on g503.

waterguy is 100% correct on propane, It can BITE you.
How about Diesel, or gasoline with "brown gas" injection. It can be
generated only when running, so no hydrogen when shutdown.

My project is the 48ft Uniflite at :
http://www.densnet.com close to the bottom of the page.
It had an engineroom fire, and I have about a mile of wire to install.
Have replaced the salon deck, and all wood that had been touched
charcoaled. I now have the 2 showers functional, and onboard water
storage, so I go to the boat for a week or two, and bust bottom. Have
been skipping that, and thank you for reminding me that nothing
happens unless I do it!
Good luck in whatever you persue
Den
48YF http ;//www.densnet.com