A question for a marine engineer...
Michael McKee
I have a question for a marine engineer that I need an answer to...
We're in the middle of yet another massive boat project, and ran into
something strainge (again). It would seem the makers of our 1973 41' Morgan
Out Island (413) felt the need to run the vent hose for our (2) 50 gallon
fuel tanks (located on the port side) all the way across the engine room to
the opposite side of the boat (the starboard side).
THE QUESTION(s):
1) Is this nessesary?
(I would much rather remove this and relocate the vent on the same side of
the boat as the tanks. I have enough room above the tanks to put a loop up
pretty high in the engine room on that side).
2) Why did they do this?
(Is there some bizzare law of sailboat/diesel fuel physics that I may not be
aware of? Is the vent hose set up like this on any of your sailboats? Does
this have anything to do with that UFO we saw while crossin the gulf
stream?)
Any help would be nice! :-)
Thanx,
Capt'n MikE
Andra...@msn.com
http://www.geocities.com/thetropics/island/6979
jameslw...@my-deja.com
As is often the case with boats, my answer would be, "It depends."
Possibilities:
1) The hose lead was easier to conceal the way it's run.
2) The tanks were originally designed to be on starboard and either
were changed to port sometime in the production cycle or on your boat
after she was built.
3) The designer felt that you were less likely to lose fuel out the
vent at extreme angles of heel with the vents crossing the boat. You
can check this with a sketch of a cross section of the tank/vent
system. This is the most likely choice, particularly if the tank width
is large relative to the distance from the tanktop to the vent.
You mention a "loop" in the vent hose. This is not a good idea.
Basically you want the vent hose to easily drain back into the tank
from any place along its length when the boat is upright. Otherwise,
if you overfill the tank, there will be fuel pushed up into the vent
hose that will be trapped there. The next time you fuel, if you have a
vigorous fuel flow, the escaping air will blow the trapped fuel out of
the vent.
Jim
s/v Sweetwater
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
Capt. Neal®
because they were designed mostly as a charter motor boat.
Because they have a relatively shallow draft, they tend to
heel excessively when hard pressed (the few times people try
to sail them in heavy winds, that is because in light winds
they are so slow that people resort to the diesel) and
consequently if the fuel vent line was on the same side of
the vessel as the tankage there is a possibility that fuel
could spill out the vent . It makes more sense and is
recognized marine construction practice to vent on the
opposite side of the (sailing) vessel from the tankage.
Your ugly dog of a vessel at least was constructed properly
with respect to this.
Respectfully,
Capt. Neal
~~~~~~~~~~~~~
Michael McKee wrote in message ...
Michael McKee
My confusion is this... When we are on port tack the tops of my fuel tanks
are well above the vent opening, and loop on the starboard side. Yet we
never noticed loseing any fuel on port tack when we have full tanks.
If I ran the vent hose out the same side of the boat as the tanks are on
(port side) the tank tops would never be above the vent opening on any tack.
This hose needs to be replaced because it's 26 years old. It's taking up
valuable room on my engine compartment wall, and (unless it's absolutly
nessesary) I don't wana run it clear across the boat if I don't have to.
If I knew the physics behind this "recognized marine construction practice"
then I think I could make a more informed decision. Can you help me there?
Thanks,
Capt'n MikE
Capt. NealŽ <Capt...@Bigfoot.com> wrote in message
news:oQlg3.6607$AU3.1...@news2.giganews.com...
Pierre Boudier
> My confusion is this... When we are on port tack the tops of my fuel tanks
> are well above the vent opening, and loop on the starboard side. Yet we
> never noticed loseing any fuel on port tack when we have full tanks.
This is because the start of the vent must be on the port side of the
tank. Thus, even if the vent opening is lower than the tank, fuel cannot
reach it because the start is on the highest point of the tank for this
tack.
On starboard tack, the vent start will get flooded but as the opening is
on the starboard side, the fuel will not reach it.
> If I ran the vent hose out the same side of the boat as the tanks are on
> (port side) the tank tops would never be above the vent opening on any tack.
On normal heel angles. But with your current layout, you are safe until
90° heel. But I admit you won't reach this every day... The choice is
yours !
--
Pierre Boudier - Marseille - mailto:pbou...@altern.org
" Quand les mouettes ont pied, il est temps de virer. "
Miltom
there fair sailors for minimum draft boat and are very well made for a
production boat. Having said that why on earth would you trash an other mans
boat even if every thing you said was true? Milton73
> the same side of
Bryon Kass
spray and they do not get submerged it is probably OK. Your
idea of setting up a loop to prevent seawater infiltration should
be incorporated in their design. If not you could change it but
with sailboats and their tendency to wet the rail the vents are
best on the stern about a foot below the shear the loop going up
min six inches before going down to the tanks. A better idea that
I have seen in navy boats is the vent outlets on deck near a self
bailing area where the vent is so high that they will not overflow
when fueling. They are higher than the fill pipes and have a loop
to prevent that water in tank problem. When fueling the fuel
should shut off the automatic nozzle without getting fuel all
over.
Bryon Kass
webmaster and
Custom Design
150 Mechanic St.
Foxboro, MA 02035
508-543-9068 or fax 508-543-5127, Foot yard 508-384-2415
in THE ENGINE ROOM http://getit.at/engineroom
Bryon Kass
the vent. This is standard industry practice to prevent seawater
from getting forced into the tanks. The loop does not have to
be very long but must be say six inches high with the vent being
in a place on the hull that will not get submerged. Best on the
stern of a sailboat a foot below the shear.
Bryon Kass
webmaster and
Custom Design
150 Mechanic St.
Foxboro, MA 02035
508-543-9068 or fax 508-543-5127, Foot yard 508-384-2415
in THE ENGINE ROOM http://getit.at/engineroom
jameslw...@my-deja.com wrote:
>
> In article <u1$Ujq1x#GA.353@cpmsnbbsa05>,
Aart Koelewijn
"Michael McKee" <Andra...@msn.com> writes:
> Hi everyone!
>
> I have a question for a marine engineer that I need an answer to...
>
> We're in the middle of yet another massive boat project, and ran into
> something strainge (again). It would seem the makers of our 1973 41' Morgan
> Out Island (413) felt the need to run the vent hose for our (2) 50 gallon
> fuel tanks (located on the port side) all the way across the engine room to
> the opposite side of the boat (the starboard side).
>
> THE QUESTION(s):
>
> 1) Is this nessesary?
Yes
> 2) Why did they do this?
This is not to prevent fuel running out, but to prevent water coming
into the tank. When you heel so much that your vent is below water, the
highest point of the vent hose will be well above water level, which
makes it very difficult for water to get into your fuel tank.
Aart
--
Aart Koelewijn | Linux 2.0.36
E-mail: aa...@mtack.xs4all.nl | my newsserver kills all
http://www.xs4all.nl/~mtack/ | Content-Type: multipart/* messages
Fredrick G Young
Michael McKee <Andra...@msn.com> wrote in message
news:u1$Ujq1x#GA.353@cpmsnbbsa05...
> Hi everyone!
>
> I have a question for a marine engineer that I need an answer to...
>
> We're in the middle of yet another massive boat project, and ran
into
> something strainge (again). It would seem the makers of our 1973 41'
Morgan
> Out Island (413) felt the need to run the vent hose for our (2) 50
gallon
> fuel tanks (located on the port side) all the way across the engine
room to
> the opposite side of the boat (the starboard side).
>
> THE QUESTION(s):
>
> 1) Is this nessesary?
>
side of
> the boat as the tanks. I have enough room above the tanks to put a
loop up
> pretty high in the engine room on that side).
>
>
may not be
> aware of? Is the vent hose set up like this on any of your
sailboats? Does
> this have anything to do with that UFO we saw while crossin the gulf
> stream?)
>
> Any help would be nice! :-)
>
> Thanx,
> Capt'n MikE
> Andra...@msn.com
> http://www.geocities.com/thetropics/island/6979
Not a marine engineer but I'm an engineer/sailor. I suspect running
the vent to the stbd side is to prevent water entering the vent in
the event of a severe heel to port. You will probably find that the
tank connection for the vent is on the extreme port side of the tank
so that a severe heel to starboard takes the fuel level below the vent
outlet on the tank.
She's good explanation? No!
Frederick
Allan Horn
I wouldn't recommend changing it. Holding tanks are often be vented the same
way for obvious reasons.
I personally think the Out Island sails great for the type of cruising
vessel she is.
Rumor has it in the St. Pete sailing circles that Catalina tried to
re-design the Out Island like they did the Morgan 36 so they wouldn't have
to pay Charlie Morgan his substantial design royalties and couldn't make it
any faster than it is already.
Every boat is a compromise... speed and comfort are opposite poles.
The Out Island 41 is very comfortable and a fairly good sailer in the right
hands.
That UFO you saw was probably my boat sailing downwind.
Regards,
Allan Horn
Captain - "Island Lady"
(Custom Heritage 38)
brian whatcott
says...
Sounds good to me!
A conservative choice would be to prevent leakage when blown flat.
There is no same side loop height that can handle this.
O the other hand - I suppose the great majority of American sail boats
never sea an off shore cruise in rough weather - these are the ones that
could use a short vent.
Brian Whatcott Altus OK
Fredrick G Young
brian whatcott <in...@intellisys.net> wrote in message
news:7mab5f$7...@enews3.newsguy.com...
You sadly underestimate American Sailors. We have a very long
coastline and we also have the Great Lakes. a) I happen to be
ex-British and b) I live two miles back from the shore of Lake
Michigan. c) My last sailboat was a 25ft Raised deck sloop in which
my wife and I cruised Lake Michigan and Green Bay. Lake Michigan is
about 300 miles long and averages about 70 miles wide. We have crosed
several times. We have been out in some pretty hard blows. Twelve foot
or so waves in fresh water can be a wild ride. They are short and
steep sided and don't need much fetch to develop. If you don't slide
down the backside you can pitchpole easily. Eight knots on a broad
reach on a deep keel boat requires one hell of a wind. That's with a
fully reefed main and no jib.
I never owned a boat in the UK. I couldn't afford it. It's much
easier here. That's why I've been here 40 years.
Frederick.
default
-Dave
from Scarborough, been here (States) 29 years.
David Smalley
>
> Hey, no such thing as ex-Brit. Once a Brit always a Brit.
Not so. I used to be a Brit then the Bahamas gained its independence.
Now I am a Bahamian and have no right to a British passport.
DAVe