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Catalina 350 extended range fuel

Jan 16, 2018
7
Hunter 30T Okinawa
I was wondering if anyone has considered installing an additional fuel tank under the port settee. An optional water tank is available, but I was considering making it a fuel tank instead....thoughts?
 
Sep 22, 2018
1,869
Hunter 216 Kingston
My mistake... I referenced the wrong boat- Cat 350 not your H 30T.

I won’t bother you again.

Fair winds
 
Oct 22, 2014
15,840
CAL 35 Cruiser moored EVERETT WA
Ben I see you have been around these forums and now have 2 new posts. Welcome.
Plans to sail your Catalina 350 around the world sounds great. Nice boat.
Considering diesel vs water, is no question for me. More water is better than diesel secure inside the boat makes best sense to me. Many boaters carry 5gal containers of diesel safely on deck in plastic sealed containers. Diesel is lighter than water and such tanks may float if lost overboard.

I note you have a sail boat. So you have two sources of power. This leads me to make water the higher priority especially during long passages.
 
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Jan 16, 2018
7
Hunter 30T Okinawa
John, Thanks for the reply. There is tankage for 77 gal of water in two tanks. With a water maker, that should be more than adequate (also can use rainwater capture) but having more fuel available would allow one to stay out a little longer. Solar into LiFEPo4 batteries would be my main source, but a solid ability to supplement with alternator power would be great! Standard is 39 gal of fuel and an additional 20.8 is a bonus....1.2 GPH would just last longer and meet my intent. I know this is an age old debate....it is a sailboat after all!
 
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Oct 22, 2014
15,840
CAL 35 Cruiser moored EVERETT WA
Ben sound like you are exploring all ideas. Water making, I have heard, depends on the quality of the water you input.

I was recently discussing this with a friend. he had participated in a class. He came away with thoughts that you can build one if you are reasonably a DIY sailor.
 

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Jul 1, 2010
861
Seaward 25, Catalina 350 Erie, Pa
We haven't added any extra tankage on our 350 (no need to on the Great Lakes), but if you don't already have a generator there, a better location for a tank might be under the port cockpit locker in the area they use for a generators. The fuel fill is located near there, as well. The settee storage area is way easier to get into for everyday storage. I'd hate to give up that storage area on our own boat.
 
Jan 16, 2018
7
Hunter 30T Okinawa
Sesmith, That's a good point. I don't know how much room is available back there with a water tank back there, but definitely worth looking into!
 
Apr 5, 2009
1,565
Catalina '88 C30 tr/bs Oak Harbor, WA
1.2 GPH sounds awful high for a 35' boat. What engine are you running. usually, your total range will increase significantly if you lower the rpm's. The extra speed at max comes at a steep drop in total range.
 
Jan 16, 2018
7
Hunter 30T Okinawa
I don't own one yet Hayden, I'm just going off of what the Universal M35B operators manual says. 1.2 gph for 2500 rpm which should give 6-7 kts.
 

SFS

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Aug 18, 2015
1,957
West Marine Kayak Tampa Bay
Wow, that's terrible fuel consumption. I have a hard to read copy of their sales material, and at 2500 rpm, it looks like the motor would be developing 30 hp. A general rule of thumb for diesels is burning 1 liter per hour per 10 hp being developed. So at that RPM/HP combo, 3L/hour (0.79 gal/hour) would be a good expectation.

If you haven't already bought a motor, you may want to consider Yanmar.
 
Oct 22, 2014
15,840
CAL 35 Cruiser moored EVERETT WA
Afraid Hayden is accurate. While your mileage may vary the Universal 35 is more stingy on fuel. The manual reports liters per hour at various rpm settings.
It looks like 2 liters per hour at 2800 rpm is stated. That would translate to a little over .52 gallons per hour.
25056A85-CA8C-4177-BD8C-8091C1B07C34.jpeg


if you wanted to identify a safety margin, till you had hard data on your engine, consider using .6 to .7 gph in your planning.

Based on the tank capacity stated of 39 gallons that would provide, conservatively, a range of 340-390 nm.
 
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Jan 16, 2018
7
Hunter 30T Okinawa
JSSailem, no disrespect intended but if I enter that performance chart at 2500 rpm then follow to the right to the GPH it falls just above 1 gph...any owners with actual numbers that differ from the performance chart I'd love to see what the consensus is of fuel burn to achieve hull speed.
 
Jul 1, 2010
861
Seaward 25, Catalina 350 Erie, Pa
Sesmith, That's a good point. I don't know how much room is available back there with a water tank back there, but definitely worth looking into!
I wasn't talking about under the aft cabin bed. I meant under the rear of the cockpit. Not sure what year your 350 is, but if it's the Mk 1 version, you would access this area from the transom locker. From the cockpit locker, you would have to remove the shelf inside to get down there. That's the spot they usually use for a generator install. I would think there's gotta be a way to fit a tank there, and somehow tee off a fill line with a valve from the diesel fuel fill back there
 
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Jul 1, 2010
861
Seaward 25, Catalina 350 Erie, Pa
Sorry, I don't keep track of fuel consumption so I've got nothing for you there. I can tell you I had the same concerns regarding fuel consumption when I checked out the performance chart referenced above when we bought our 350 a couple of years ago. We have a 1gm10 on our other boat, and it definitely uses more fuel than that one :) , but I've found the M35b engine on the Catalina to be a great motor. Extremely smooth running and quiet and dependable as heck.

Don't know what the concern would be insisting on motoring at hull speed. We back it off a bit, and it seems to me to be a pretty efficient engine (though I don't keep track). When we have to motor, we do as much motor sailing as possible, so that stretches the fuel out more, and makes it impossible to really track fuel usage when we're cruising up on the Great Lakes. So many variables anyway...prop on boat, wind, waves, current, etc., so I wouldn't really get hung up on the fuel consumption graphs. A 3 cyl yanmar isn't that much more efficient than the M35b, doesn't have as much HP as the M35b, and is a 3 cyl where the M35b is a 4 cyl, so all things considered, not sure you would get any better fuel consumption with a yanmar, on that boat. Keep in mind, the 350 is a very big 35' boat.
 
Aug 7, 2018
179
Catalina 350 Great Sodus Bay, Lake Ontario
I have noticed a huge difference in fuel burn based on sea state. We see .75 per hour in seas under 3'
 
Apr 5, 2009
1,565
Catalina '88 C30 tr/bs Oak Harbor, WA
If what you are looking for is to maximize your range with the available fuel on board, SPEED is not your friend.
Here is a spreadsheet I found a long time ago created by a C42 owner after careful tracking of metered fuel at different rpms. On his boat with his prop and engine, he got the maximum range (miles per tank) at 1900 rpm which was the lowest speed he tested. It is a myth that you must run your engine at max throttle. They do not like to idle but the over the road trucks run for hundred's of thousand's of miles at 1500 rpm which is about 60 mph. IF you are worried about carboning up your mixing elbow run it harder for 15 minutes every 3-4 hours. I have not gone over 1900 RPM on my M25XP for 20 years except for short periods when i needed to push through a current. I have removed the mixing elbow several times and it is clean.
YMMV (your mileage may vary)
 

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