Heating System Question?

[Sandero]

I am an architect and not a HVAC engineer. A boat is has a reasonable small interior volumne but much less insulation that a typical house and the system may need to perform in varied climate.

If cost is a consideration... and it usually is... AND installation is a biggest component of the cost... installing two systems AC and Heat is clearly a spendy solution albeit it offers the optimum for heating and cooling. Tubing for hot water may be easier to run than ducts... but marginally so. Depends. Once the air has reached design temp the duct height would be less critical. In my sailboat I have 3 outlets grilles one in each cabin and it provides very even heat. The furnace itself is hardly larger than an elongated football and does not take up much space. Hot water is generated by engines and can be stored and there is usually no need for a boiler unless the motor or generator is not running (much). The ducts can also be used for unconditioned ventilation and with AC system can use the same ducts. The air velocity is not high velocity and the system is very quite as the blower is part of the heater. These units are robust and very high tech. I've had positive experience with diesel fired forced air heating. YMMV.

[chrisjs]

GG

No sure about being pessimistic but did have a friend who needed to liver aboard a 45ft boat there for a few winters. I just remember how nasty it was much of the time. Either cold or wet (inside and outside) and slippery docks.
But your article paints a different picture. Have you actually wandered down to the docks there and chatted with people who live aboard? It might help provide some insight into the reality vs the fantasy. Sure the bigger the boat, the better the heating system, etc, etc, the better the experience may be, but it is still a boat in a New England winter. We do have several couples who live on their boats at our marina but IMO they all do it for financial reasons. I guess it is better than trailer!!

[Stu Jackson]

I'm surprised no one has mentioned the basic differences between hydronic (water piped to radiators) and forced air boat systems.

Hydronic:

-- easier to install, no ducts, just pipes
-- easier zone/room control, fans on the back of the coils can be hooked to thermostats
-- can heat hot water, too
-- usually result in condensation because it only reheats the air already in the boat (breathing creates moisture, so does cooking)

Forced air:

-- usually eliminates condensation inside because it heats outside air being drawn in through the system
-- requires more space for ducts, usually 4 to 6 inches round

The other issues to consider are

-- How will you heat hot water for showers and cooking/cleaning dishes & pots and pans? If you're tied up to a dock and have electricity, then you could use that for your hot water, rather than "needing" a hydronic heating system. With no dockside power, which some marinas may turn off in the winter, this is a VERY basic issue you need to deal with.

-- How much can you reuse your ducting from your AC system? One post did mention combining a hydronic system to place "radiators" (i.e., heating coils) in those ducts. This has great merit if you can find a source of outside air to avoid condensation. We simply don't know enough about your existing system to make definite recommendations.

I'm not an architect , just an HVAC engineer.

I think you've got a wealth of ideas here. Most likely the folks you find up north, who do design and installation, will have some other ideas for you to consider. Just remember, there is never only one right answer to these types of issues, unlike math tests in high school.

Since this is not a unique or new subject, you could also Google "advantages & disadvantages of hydronic and air systems" for more technical information about systems and condensation, etc. and why and how it happens.

Good luck.

[chrisjs]

GG
2 other important considerations for living aboard in Boston during the winter in additon to heating.

You will need to have a sewage treatment system on board because there will be no pump-out boat. Also need to make sure whatever your system is that is "legal" in Boston. It can be a very long way from the boat to the shore-based head in the middle of snow storm on a dark night.

You also need to check into how you will get fresh water to your boat. Marinas turn off dockside water faucets so that they do not freeze. At our marina, people rig a hose from the shore-based high pressure outlet that they bring to their boats as needed. Absolutely no continuous water connection. Worth checking out what they do at Constitution.

Not being pessimistic, just wanting to make sure you have considered other matters!!

[foggysail]

Originally Posted by GalaxyGirl

Chris, your such a pessimist.

Have you read this story.

YEAH! But you will gain a sense of reality in Boston beginning in December and peaking in January/February with the water temperature in the low 30's that will surround your boat's 1/2" thick at most hull. All the while a stiff NE 20MPH breeze outside is blowing snow at 1"/hour. And you might want to consider adding a couple of water circulators into the bay near your hull to prevent the boat from being crushed by floating ice.

Your kids will thrill at the challenge of navigating the daily trudge from your boat to shore without drowning..... but a few life jackets will prevent that although not hypothermia should they have a bad day.

And of course carting groceries, laundry and as earlier mentioned fresh water through the elements just adds to the excitement! You may even be able to entice one of the popular TV reality shows to feature your large family's endeavor!

[GalaxyGirl]

Originally Posted by chrisjs

GG
2 other important considerations for living aboard in Boston during the winter in additon to heating.

You will need to have a sewage treatment system on board because there will be no pump-out boat. Also need to make sure whatever your system is that is "legal" in Boston. It can be a very long way from the boat to the shore-based head in the middle of snow storm on a dark night.

You also need to check into how you will get fresh water to your boat. Marinas turn off dockside water faucets so that they do not freeze. At our marina, people rig a hose from the shore-based high pressure outlet that they bring to their boats as needed. Absolutely no continuous water connection. Worth checking out what they do at Constitution.

Not being pessimistic, just wanting to make sure you have considered other matters!!

Chris, thanks for pointing those things out!

I actually won't be at Constitution, I'll be around the corner at Yacht Haven. I spoke to the Dockmaster there, he told me that in the winter the liveaboards get moved to spots close to the pump-outs. But, they are also renovating there docks to include pump-out at every slip I have been told.

They also do the same with long hoses to the clubhouse faucet for fresh water.

I took a visit there last week and some of the docks have been completed. They have made them much wider. I was pleasantly surprised just how wide they are now. Certainly won't have to worry about kids sliding off the deck

[GalaxyGirl]

Originally Posted by Stu Jackson

I'm surprised no one has mentioned the basic differences between hydronic (water piped to radiators) and forced air boat systems.

Hydronic:

-- easier to install, no ducts, just pipes
-- easier zone/room control, fans on the back of the coils can be hooked to thermostats
-- can heat hot water, too
-- usually result in condensation because it only reheats the air already in the boat (breathing creates moisture, so does cooking)

Forced air:

-- usually eliminates condensation inside because it heats outside air being drawn in through the system
-- requires more space for ducts, usually 4 to 6 inches round

The other issues to consider are

-- How will you heat hot water for showers and cooking/cleaning dishes & pots and pans? If you're tied up to a dock and have electricity, then you could use that for your hot water, rather than "needing" a hydronic heating system. With no dockside power, which some marinas may turn off in the winter, this is a VERY basic issue you need to deal with.

-- How much can you reuse your ducting from your AC system? One post did mention combining a hydronic system to place "radiators" (i.e., heating coils) in those ducts. This has great merit if you can find a source of outside air to avoid condensation. We simply don't know enough about your existing system to make definite recommendations.

I'm not an architect , just an HVAC engineer.

I think you've got a wealth of ideas here. Most likely the folks you find up north, who do design and installation, will have some other ideas for you to consider. Just remember, there is never only one right answer to these types of issues, unlike math tests in high school.

Since this is not a unique or new subject, you could also Google "advantages & disadvantages of hydronic and air systems" for more technical information about systems and condensation, etc. and why and how it happens.

Good luck.

Thanks for the input Stu. I'll opt for the forced air system. I don't want to deal with condensation at all. I'm hoping that I can add a furnace to the existing ductwork, but I guess I won't know for sure until I have an HVAC engineer take a look.

[Kenomac]

We have three zone diesel heat which is awesome and cheap to use. If the electric is included at your future berth, just go with electric baseboard heaters which is what we use whenever we can or mini ceramic heaters.

[psneeld]

Originally Posted by GalaxyGirl

Thanks for the input Stu. I'll opt for the forced air system. I don't want to deal with condensation at all. I'm hoping that I can add a furnace to the existing ductwork, but I guess I won't know for sure until I have an HVAC engineer take a look.

Whoaaa Nellie...the condensation issue isn't such a simplistic answer....you'll get condensation on a boat no matter what heating system you use....just depends on where and how much AND how extensive is your system in circulating "less humid air" to the right areas..

Hydronic systems can be outfitted to reduce condensation and cheaply installed forced air systems aren't gonna cure all moisture problems....

That's why I have been posting that when you decide on a system or still need to...either wait a year and show your boat to guys that you have seen and heard the results of their work...or research the heck out of it now and take it to the right place after deciding...but to say one system is better than another sure depends on a lot...usually starting with the boat which you don't have yet.

[rw58ph]

They can be installed at the boat. The installer came to the boat. The Webasto diesel boiler keeps the Eagle warm and bone dry. No condensation. We started out with three zones but changed to one as it’s cheaper to heat the entire boat at one time and utilize the hot water. Also heats the hot water. The boiler produces 100,000 btu sized for temps down to 0 degree F. The forced air may not hold the heat for the longer runs at least on the 58 ft Eagle it would not.

[GalaxyGirl]

Originally Posted by rw58ph

They can be installed at the boat. The installer came to the boat. The Webasto diesel boiler keeps the Eagle warm and bone dry. No condensation. We started out with three zones but changed to one as it’s cheaper to heat the entire boat at one time and utilize the hot water. Also heats the hot water. The boiler produces 100,000 btu sized for temps down to 0 degree F. The forced air may not hold the heat for the longer runs at least on the 58 ft Eagle it would not.

That's good to know that they can come to the boat!

Phil, what does the fuel typically run you on the Eagle for a winter season?

[rw58ph]

400 to 500 gallons. We run the Webasto, 24/7 from October through April

above 50 – use electricity.
40 to 50 – 10 gallons per week
30 to 40 – 15 gallons per week
20 to 30 – 20 gallons per week
0 to 20 – 20+ gallons per week

Very seldom does the temp go below 20.

Its important to have the boiler sized correctly as you do not want the burn period to be to long or to short. I do not like to recommend brand names as it’s important to have parts and service in the area. I have the boiler service every September, so its been very reliable. The major bands are Espar, Hurricane, Kubota and Webasto. For your size boat and area you will at least need 100,000 btu. Also 60% of the heat exchanges should be down in the staterooms/low as heat rises. The only real maintenance is checking the coolant lever every month and transfering diesel to trim the boat. The Webasto draws and returns from the port tank and since the boiler draws more than it uses it also clean/polish the fuel like most diesel engines.

[GalaxyGirl]

Originally Posted by rw58ph

400 to 500 gallons. We run the Webasto, 24/7 from October through April

above 50 – use electricity.
40 to 50 – 10 gallons per week
30 to 40 – 15 gallons per week
20 to 30 – 20 gallons per week
0 to 20 – 20+ gallons per week

Very seldom does the temp go below 20.

Its important to have the boiler sized correctly as you do not want the burn period to be to long or to short. I do not like to recommend brand names as it’s important to have parts and service in the area. I have the boiler service every September, so its been very reliable. The major bands are Espar, Hurricane, Kubota and Webasto. For your size boat and area you will at least need 100,000 btu. Also 60% of the heat exchanges should be down in the staterooms/low as heat rises. The only real maintenance is checking the coolant lever every month and transfering diesel to trim the boat. The Webasto draws and returns from the port tank and since the boiler draws more than it uses it also clean/polish the fuel like most diesel engines.

Thanks for the info Phil!

What does "transferring diesel to trim the boat" mean?

[Sailmonkey]

Originally Posted by GalaxyGirl

Thanks for the info Phil!

What does "transferring diesel to trim the boat" mean?

Often on a larger power boat you'll need to move fuel from one tank to another to level out the boat. As is the case here, the heater draws fuel from one tank, leaving a number of others full. When that occurs the boat will list in the direction of the full tanks. The solution is to evenly distribute the fuel to keep the boat level.

[atoll]

hope fully the boat you are buying is insulated for the cold,not the tropics,assuming it has any insulation at all!

most boats around here have 2 inches of spray foam insulation through out for the uk winter! if the boat is not properly insulated,fiberglass boats tend to rain inside as any heating just condenses on the cold outer skin of the vessel!

if you plan on buying a boat for a cold climate consider insulation issues very seriously