2GM20F - Sea Strainer

Sep 21, 2004
16
Hello All:
Almost have V2947 'emptied' in preparation for winter festivities.
Heaviest job, literally, was today, removing 1-12V and 2-6V batteries
for the cold storage season. Would probably have been easier had the
boat not been on a 'yard' trailer with the gunwales about 8' feet in
the air; anyhow, all done (including my rickety old back which is
done 'in') I'll feel it tomorrow I'm sure.
The question for those with Yanmar 2GM20F's:
The direct distance from the thru-hull to the engine intake, both at
the forward end of the engine, is less than a foot with the engine
intake slightly aft and inboard of the thru-hull.
The current setup has about 18 inches (or less) of hose length from
thru-hull to intake with a very, I say very pronounced, inverted 'U'
shape.
The 'arms' of the inverted 'U' are probably no more that 4 inches
apart; God knows how the installing mechanic bent the hose to make it
fit.
Immediately outboard of the thru-hull (like, maybe 3 inches) is the
wooden 'bulkhead' of the engine compartment; directly forward of the
thru-hull is the removeable '2 step' panel. There is very little room
(inches) above the 'top' of the inverted, 'U' shaped hose. Suffice
to say, she's a tight fit.
Cutting to the chase, this beautiful, almost new Yanmar does not have
a sea-strainer. I'm a little concerned about sucking all manner of
waste into the engine without the benefit of a strainer to cut the
heavy crud (wheat) from the crustacean waste (chaff).
My mechanic 'for now' is not all that familiar with Yanmars and
suggested installing a huge plastic strainer on the engine
compartment bulkead but AFT of the engine and on the side opposite to
the thru-hull/intake. To do so would mean at least 3 feet of hose
from thru-hull to strainer and another 3 feet back to the engine
intake.
If there's one thing the less than detailed Yanmar manuals emphasize
is -"shortest distance possible between thru-hull and engine
intake!". Six feet of hose doesn't sound to me like 'shortest
distance possible'.
I'd appreciate all suggestions, advice, guidance from those who have
done the sea strainer routine with a 2GM20F including strainer
make/model that worked for you in these very confined spaces.
Cheers all,
Geoff Warren
V2947
Powell River, BC
 
Oct 31, 2019
562
Hi Warren;

About 6 years ago I replaced the old Albin 0-21 gasoline
with a 1GM10 Diesel engine, and I'm very satisfied. (I
couldn't fit a 2GM10, and as it turned out, I think I
didn't need the 2GM10)
I did have a problem this year- there was an obstruction in
the exhaust (don't ask me how it got there)and water backed
up into the engine with the result- I had to buy another
1GM10. It's installed again, and a new exhaust system! It
has cost me dearly!
But that doesn't answer your question about the water
intake. I can only tell you what I have. The seakock is on
board--side, offset and just about even with the back side
of the engine. The intake hose runs like an 'S' from the
seakock first up, then curving down under the Oil filter
and then up again to the intake (where the impeller is).
Where the hose curves down, there is a sea water strainer
(plenty of room and easy to maintain). I guess the total
length of the hose is about 1 foot.
A word of advise: get 2 (or more) impellers (and gaskets).
They are inexpensive, and do fail, but are easily replaced
(when you have one aboard)
I sail 12 months of the year, hence I don't worry about
freezing. But 'up North' I would disconnect the intake hose
from the engine, just to make sure there's no water left
inside.
Wilhelm, V-257
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Oct 31, 2019
562
Hi Warren;

I've made a mistake! I was looking back from the cabin to
the engine and said the seakock is on board-side
 
Sep 21, 2004
16
Thank you Wilhelm; I know all about getting old and the memory is the
second thing to go.......
I've checked the trusty Yanmar Installation manual and the size of
the 1GM versus the 2GM doesn't appear to be drastically different.
That said, there's just doesn't seem to be enough room with my setup
to mount the strainer which was shown to me by my mechanic without
going aft of the engine -the bloody thing was huge, circular plastic
about 6 inch diameter and 6+ inches high; gotta be something
smaller. Do you have any idea of the brand/model of your strainer
and its rough dimensions.
I'll be back down to the boat after Xmas and will take a closer look
into the great black hole with your description in hand.
Thanks again Wilhelm,
Geoff
(I'll have to change my ID, family name's Warren, given name's Geoff

--
- In AlbinVega@yahoogroups.com, WL wxt8981@y... wrote:
 
Oct 31, 2019
70
Hi- I sail a 1gm Yanmar on fresh water lake with a small 2" diameterX3" strainer--works well--plastic case with ss screen. love my little diesel--very frugal--I cruise at 200-2200rpm 5-5.5 knots on a two ton Mirage 25' sailboat. Can't wait to sail again in the early spring. jorgen the viking
 
Apr 30, 2000
197
Hello: I have a 2GMF in my Vega and installed a strainer (smallest Groco
available) on the port side above the alternator in the engine compartment.
Just enough room and gets it just above waterline so it can be opened for
cleaning without flooding the boat. I closed off the original starboard side
intake and used the port side inlet that was originally for sea water to the
sink. A check valve in the line to the sink keeps it from pulling air from the
sink discharge. Works great for the past 6 years. Bill Bach V 1071
 
Sep 21, 2004
16
Thank you Jorgen and Bill:
I should have warned everyone that inboard diesels and sailboats over
21 feet are foreign to me; gonna be a steep learning curve just to
master the mechanics, never mind the 'everything is bigger' syndrome.
Please excuse the neophyte or just plain dumb questions.
J's 2"X3"+/- strainer sounds like it may work in my limited space
available; Bill, my thru-hull/engine inlet are both on the starboard
side and I assume yours are the same. Where/how'd you run the hose to
get it from the port 'sink' thru-hull to the stbd engine intake.
Obviously I'm going to have to study my engine compartment layout
and limitations a lot more closely.
Geoff V2947
 
Jan 28, 2001
694
We just used a slotted covers over our thruhulls and they seemed to work
okay. I wonder though if they may have contributed to our problem with the
eventual clogging in the exhaust loop. When we went down the pacific coast a
buddy boat with us had to stop frequently to clean the krill out of there
stainer. I'm sure we must have been sucking them up and pumping them through
the heat exchanfer also. All in all, I like the idea. More than one boat has
overheated after sucking aplastic trash bag into their intake. We have a
dual intake with thruhulls on the port and starboard side. One of them also
works for the sink. We also have a ball valve arrangement that allows us to
pump from the bilge as needed. West Marine sells a srainer made out of
bronze with a screen on the bottom for attaching to hoses in the bilge. Not
recomended! The metal screen corrodes away and falls apart. Walt
 
Sep 21, 2004
16
Thank you Walt. I've got the winter to sort it out and she certainly
won't sink or otherwise go astray sitting on the yard trailer. Steve
Demont put all new thru-hulls on the boat not long ago (together with
a whole bunch of other new 'stuff') but the one thing that the
surveyor, my skipper on the trip Seattle to Powell River, and my
mechanic all said when they first looked at the engine, "you need a
sea-strainer installed".
I've now got some great ideas to percolate on while eating left-over
turkey for the next (hopefully) short while. I like your idea for
simplicity reasons alone and I'm going to survey some of the sail and
power boaters in our harbour to see how many of them here in our neck
of the woods go simple or invest in a strainer. Also gives me an
excuse to visit all the chandlery outlets within a reasonable
distance to compare strainers without Marj accusing me of shopping
for 'boat junk'.... Geoff

-- In AlbinVega@yahoogroups.com, "walt/judy brown/allore"
bestvega@h... wrote:
 
Apr 30, 2000
197
Mine's an older Vega, previously gasoline. The newer ones must have a
different through hull arrangement. Bill Bach V1071