Winterizing questions

[jmmeis]

I recently purchased a 30' O'Day that has a Yanmar 12hp diesel. The marina where I have the boat stored is winterizing the engine for me, however I am doing the rest myself. Never having owned a diesel, what is my best bet for winterizing the fuel? Should I fill it up (11.5 gallon tank) and put in an additive? Should I put in the additive with whatever is in the tank? What is the best additive? Your comments are appreciated! jmmeis

[Vasco]

Would help if we knew where the boat is. I'm guessing northern hemisphere but how far north?

[CaptTom]

Couldn't you ask about something non-controversial, like anchors?

Here's the deal: there is not good agreement on the question whether to leave tanks full or empty, nor the question about which (if any) additive to use.

My personal opinion, after a half-century in the Northeast US, is that you leave the tank full and only use only biocide (like Bio-Bor) to keep any bugs at bay.

My reasoning is that I've personally witnessed LOTs of condensation on the inside and outside of tanks, bulkheads and just about anything else when warm, moist air shows up after a cold spell.

I've also witnessed filters that were bio-fouled, as well as many engines that ran just fine on diesel that's left untreated. Since the engines don't seem to need any other additive, the only thing I worry about is keeping bugs from growing.

One final point; many engine manufacturers recommend completely evacuating the entire fuel system, or, if you can't do that, leaving the tanks full.

Someone will no doubt chime in with the math to prove that there's no way condensation can happen, so it doesn't matter either way. I'm not saying I don't believe them, just saying what I've seen, and what's worked for me over a lifetime of boating.

[John_Trusty]

Welcome to the forum, Jmmeis!

+1 Vasco's comment - you gotta tell us more. Putting some of that info in your signature box will avoid having to type it in at each post because "location, boat, year, engine, etc." are going to be the first questions your fellow sailors will ask.

You can get some great info on this site with a quick Google search on the top right hand of the page. Try "winterize diesel". The yard is just going to run engine antifreeze into the raw water inlet. "The rest ..." is a long list depending on your boat. Is the your fresh-water side well mixed with antifreeze (like a car)? Are you winterizing the fresh water system and head? Removing soft things like cushions to avoid mold? I make a list, and (every year) when I find damage in the spring I remember to add it to the list.

I'm about the same distance to the pole as Vasco (45 degrees) and I use StarTron Enzyme diesel additive all year, so that's just what's in the tank. I don't know if it's "best", but it seems to work good enough.

Always fill up fuel tanks to the max when leaving for long periods. The number one source of diesel issues is water in the fuel. In winter, this largely comes from the atmospheric water in the tank space above the fuel level. As temperatures rise and fall over the day, it rains in your tank! Minimize that space by filling the void up with diesel fuel right before you store.

[jmmeis]

Originally Posted by John_Trusty

Welcome to the forum, Jmmeis!

+1 Vasco's comment - you gotta tell us more. Putting some of that info in your signature box will avoid having to type it in at each post because "location, boat, year, engine, etc." are going to be the first questions your fellow sailors will ask.

You can get some great info on this site with a quick Google search on the top right hand of the page. Try "winterize diesel". The yard is just going to run engine antifreeze into the raw water inlet. "The rest ..." is a long list depending on your boat. Is the your fresh-water side well mixed with antifreeze (like a car)? Are you winterizing the fresh water system and head? Removing soft things like cushions to avoid mold? I make a list, and (every year) when I find damage in the spring I remember to add it to the list.

I'm about the same distance to the pole as Vasco (45 degrees) and I use StarTron Enzyme diesel additive all year, so that's just what's in the tank. I don't know if it's "best", but it seems to work good enough.

Always fill up fuel tanks to the max when leaving for long periods. The number one source of diesel issues is water in the fuel. In winter, this largely comes from the atmospheric water in the tank space above the fuel level. As temperatures rise and fall over the day, it rains in your tank! Minimize that space by filling the void up with diesel fuel right before you store.

Thank you for the information. I am located in the northern part of Illinois. The boat will be stored outside with a cover. Temperatures will dip below zero several times throughout the winter.The engine is the original Yanmar 12 HP installed in 1978 and rebuilt in 2010. I will remember to put more information in the forum in the future.

[Vasco]

This is what I've been doing for the last thirty odd years. I try to top up the fuel. Sometimes I'm a few gallons short but I don't worry about it. I have a Racor water separator. I do not treat the fuel and have never had a problem as it seems it's too cold for anything to grow in it. Down south I always treat the fuel with Startron.

The engine, I run a couple of gallons of plumbing antifreeze through. On a raw water cooled engine remove the thermostat first. On a fresh water cooled engine just run anti freeze through.

I empty the fresh water tanks.. Make sure the hot water heater is drained. I then connect the in and out of the hot water tank and run a gallon of potable anti feeeze through the system making sure all the taps are open.

I remove the upholstery and anything in the boat that can freeze.

Make sure all scuppers and cockpit drains are clear and water will drain out when on the hard. I think that's about it.

Oops, one more thing, I usually change the oil and filter before hauling although I might skip that step this year as, with the high water levels and no power on the flooded docks, I only went out twice this season.

[rognvald]

Also, always change the T-fluid when you change the oil. Any metal shavings/contaminants will be removed and will not stew over Winter. I have done so for 27 years. Good luck and safe sailing.

[boatpoker]

25yr. liveaboard/cruiser. Spent many winters in Toronto others in Bahamas. Always left my tanks full over winter and have never in my life put in an additive. The refineries already do that. Never had an issue.

[S/V Illusion]

When I pulled an old fuel tank from our boat in Rhode Island, I sealed all fittings after emptying and left it behind the barn next to the shoreline all winter. Guess what - no condensation!

Old myths die hard.

What some fail to do is seal the vent line which allows some transfer to ambient air allowing temp changes to condense inside the tank. If it is properly sealed isolating it, only whatever air inside a tank can contribute condensation. In small tanks, the amount is negligible.

[donradcliffe]

Originally Posted by S/V Illusion

When I pulled an old fuel tank from our boat in Rhode Island, I sealed all fittings after emptying and left it behind the barn next to the shoreline all winter. Guess what - no condensation!

Old myths die hard.

What some fail to do is seal the vent line which allows some transfer to ambient air allowing temp changes to condense inside the tank. If it is properly sealed isolating it, only whatever air inside a tank can contribute condensation. In small tanks, the amount is negligible.

Sounds like a great physics experiment to prove Gay-Lussac's Law. Depending on when you sealed it, the tank will either bulge or crumple.

[S/V Illusion]

Originally Posted by donradcliffe

Sounds like a great physics experiment to prove Gay-Lussac's Law. Depending on when you sealed it, the tank will either bulge or crumple.

Only if the pressure delta is variable which isn't the case here or with fuel tanks in-situ.
Admittedly, it was a gross unreplicated experiment but sufficient to invalidate the myth.

To me, the option of dealing with old fuel by filling a dormant tank wasn't necessary and now,living in Florida where sailing is a year- round sport, it's a moot point.