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07-11-2024, 08:27
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#76
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Writing Full-Time Since 2014
Join Date: Nov 2008
Location: Deale, MD
Boat: PDQ Altair, 32/34
Posts: 10,279
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Re: Unattended diesel heaters
Lots of hypotheticals. I would like to hear from people that have been around furnace fires. I've experienced a few in industry. With oil-fired furnaces the most common are:
- Ignition failure (but the fuel pump is running). The flame sensor should be fail-safe.
- Dripping fuel nozzle/poor atomization. In other words, the flame is there, but some of the fuel is dripping below and accumulating. Normally there is no sensor for this. Smoke is one hint, visible before it becomes critical. Good maintenance.
- Fuel leaks on the pressure side of the pump. Fuel accumulates somewhere and the flame3 eventually ignites it.
- Plain old chimney fire. The heater has been miss-firing intermittently for months, carbon and oil have accumulated in the flue, and one day it ignites. I've seen that one. Just smoke on an industrial furnace, but the flue was orange. Do you have enough spacing?
The fire from these can be in/under the unit, and they can also extend up the flue, since the heat results in too much fuel for the air until it burns up. Hope you are on a non-combustible surface and that the flue can contain flames without overheating for 5-20 minutes. The thermostat may cut the heater if the cabin overheats, but that can be too late.
Wiring fires are rare. If they happen inside the unit it's a safe area ... unless the wire runs next to a fuel line (common), in which case it can be very bad. I once watched a fire start when a wire run through the same bulkhead as a code-compliant fuel line chafed and overheated, melting the fuel line and starting the fuel tank draining into a pool of burning fuel. The only thing that stopped a disaster was that we were late leaving works and saw it start. Several guys were covered in dry chem extinguisher dust; that part was pretty funny.
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Other than good maintenance, what saves you is good spacing from combustible materials, and I'm not sure any/most boats meet these:
- Not on a combustible floor.
- Spacing on all sides from combustible materials. In home furnaces some of this is provided by the physical size.
- Spacing and insulation requirements for flues. I don't see boat heaters meeting these requirements. There just isn't enough space.
I just installed a heater in my daughter's house, and the code requires 8 inches all around on the flue pass throughs. It's not hard to build a flue that can operate in small space when the heater is operating normally, but the requirement is for chimney fires, where are not that rare in oil heaters for the reasons given above.
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The only advise Esperspacher gives is to "Check with the boat marina and your marine insurance policy to see if the heater can be operated
when the boat is unattended." The answer may be no. Reflex and Dickenson say no.
I think unattended operation on boats falls in the catagory of common, probably safe, but not actually recommended, or permitted in many cases.
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07-11-2024, 09:00
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#77
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Senior Cruiser

Join Date: Sep 2014
Location: puget sound washington
Boat: 1968 Islander bahama 24 hull 182, 1963 columbia 29 defender. hull # 60
Posts: 13,100
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Re: Unattended diesel heaters
Quote:
Originally Posted by GordMay
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Yes delta marine in Seattle.
4.5 million dollar yacht. Built 26 years ago owner likely didn't pay for fire suppression upgrades on refit in 2016.
That is a cheap yacht for delta. They have vessels that spend 10x that just on a refit.
Nice kit from delta fire in England.
Now as to my boat. I am installing several self deploying fire bombs or what ever you want to call them 2 in my engine space . One over my galley stove. One on side of my mast in main salon one in vee berth space one in the deck locker I have my diesel forced air furnace. And one in the lazerette where I also have my legal installed propane system.
https://www.amazon.com/gp/product/B0...N2Y5S5UYO&th=1
__________________
Non illigitamus carborundum
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07-11-2024, 09:04
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#78
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Registered User
Join Date: Sep 2015
Location: PNW Puget Sound
Boat: 1955 G L Watson 40' Yawl
Posts: 417
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Re: Unattended diesel heaters
Quote:
Originally Posted by thinwater
Lots of hypotheticals. I would like to hear from people that have been around furnace fires. I've experienced a few in industry. With oil-fired furnaces the most common are:
- Ignition failure (but the fuel pump is running). The flame sensor should be fail-safe.
- Dripping fuel nozzle/poor atomization. In other words, the flame is there, but some of the fuel is dripping below and accumulating. Normally there is no sensor for this. Smoke is one hint, visible before it becomes critical. Good maintenance.
- Fuel leaks on the pressure side of the pump. Fuel accumulates somewhere and the flame3 eventually ignites it.
- Plain old chimney fire. The heater has been miss-firing intermittently for months, carbon and oil have accumulated in the flue, and one day it ignites. I've seen that one. Just smoke on an industrial furnace, but the flue was orange. Do you have enough spacing?
The fire from these can be in/under the unit, and they can also extend up the flue, since the heat results in too much fuel for the air until it burns up. Hope you are on a non-combustible surface and that the flue can contain flames without overheating for 5-20 minutes. The thermostat may cut the heater if the cabin overheats, but that can be too late.
Wiring fires are rare. If they happen inside the unit it's a safe area ... unless the wire runs next to a fuel line (common), in which case it can be very bad. I once watched a fire start when a wire run through the same bulkhead as a code-compliant fuel line chafed and overheated, melting the fuel line and starting the fuel tank draining into a pool of burning fuel. The only thing that stopped a disaster was that we were late leaving works and saw it start. Several guys were covered in dry chem extinguisher dust; that part was pretty funny.
---
Other than good maintenance, what saves you is good spacing from combustible materials, and I'm not sure any/most boats meet these:
- Not on a combustible floor.
- Spacing on all sides from combustible materials. In home furnaces some of this is provided by the physical size.
- Spacing and insulation requirements for flues. I don't see boat heaters meeting these requirements. There just isn't enough space.
I just installed a heater in my daughter's house, and the code requires 8 inches all around on the flue pass throughs. It's not hard to build a flue that can operate in small space when the heater is operating normally, but the requirement is for chimney fires, where are not that rare in oil heaters for the reasons given above.
---
The only advise Esperspacher gives is to "Check with the boat marina and your marine insurance policy to see if the heater can be operated
when the boat is unattended." The answer may be no. Reflex and Dickenson say no.
I think unattended operation on boats falls in the catagory of common, probably safe, but not actually recommended, or permitted in many cases.
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Well thought out answer. I'm an old timer and tend to be mystified by the complexity of layer upon layer of systems on boats these days.
Simplicity=good nights sleep...
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07-11-2024, 09:08
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#79
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Registered User
Join Date: Sep 2015
Location: PNW Puget Sound
Boat: 1955 G L Watson 40' Yawl
Posts: 417
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Re: Unattended diesel heaters
Quote:
Originally Posted by GordMay
Some thoughts on “Fail-Safe”:
Fail-safes are built in response to specific sources of failure. They don’t counteract all anticipated sources of failure. Nor do they counteract unanticipated sources of failure, except coincidentally.
Fail-safe devices, or systems, are not meant to prevent accidents, or failures from occurring.
Instead, Fail-safe devices, or systems are put in place, for when things do go wrong. Fail-safe systems prevent a situation from getting worse, when it fails.
Fail-safes are built with the expectation, that failure situations will, eventually, happen.
They prevent/ mitigate anticipated unsafe consequences, when failure does occur.
So, for instance
In building access control security:
Fail safe products are unlocked, when power is removed. Power is applied, in order to lock the door, and prevent access.
Fail secure products are locked, when power is removed. Power is applied, in order to unlock the door, and allow access.
In traffic signalling:
Because the light bulb is the main element of a traffic signal, a very simple conventional attitude was taken, to harness the unique failure mode of the light bulb: whenever a sign will not be illuminated, in any aspect, the signal shall then be considered to have the most restrictive aspect, that is, red aspect.
Thus; a driver, faced with a failed [switched off] signal will always stop, and activate degraded modes of operation, in order to continue.
In liquid/gas combustion appliances:
Fail safe flame detection products [thermocouple & fuel solenoid valve] are opened, providing fuel flow, only when power is applied [thermocouple detects heat of flame].
Of course, valves can experience other failures. Shafts can stick. Springs can break. Seals can become fouled. That means that a fail-close valve could fail in the open position.
This is where, attended only usage, becomes important.
Intrinsically safe systems, are based on using components with well-established, and limited, failure modes; and that in the event of fail , a safe operating condition is maintained.
For instance, 'intrinsically safe' is used to describe any device, that is unable, in any condition, to ignite volatile materials, and cause an explosion.
There's no such thing, as "fool-proof". “Never underestimate the ingenuity of fools. The best we can do is fool-resistant.”
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Great post! Thanks.
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07-11-2024, 09:16
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#80
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Registered User
Join Date: Sep 2015
Location: PNW Puget Sound
Boat: 1955 G L Watson 40' Yawl
Posts: 417
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Re: Unattended diesel heaters
Quote:
Originally Posted by newhaul
Not quite correct.
Yes the brea,ers and fuses could malfunction very rare event they fail in the vlosed position.
My boat does have full vessel fire suppression it's cheap now days
I know of several ' mega" yachts that do have fire suppression throughout the vessel.
My youngest builds them . He works for delta marine. ( Google them)
As to leaving seacocks open when not on the vessel. If I close all of my seacocks I would sink at the dock. My cockpit drains are properly installed with seacocks to isolate if hoses get damaged. And yes factory installed in 1963.
In my area most boats that sink at the dock sink due to dead batteries and clogged drains. Not open seacocks.
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And then there was the disaster of a friend of mine who routinely left his galley sink seacock open. A heavy snow, unable to get to the boat, weight of snow caused sink drain to become below new water line, 60' boat sank at the dock. All it takes is an unforseeable series of events. Also, routinely operating seacocks helps prevent failure. Again, just my opinion.
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07-11-2024, 09:35
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#81
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Senior Cruiser

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 51,818
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Re: Unattended diesel heaters
Quote:
Originally Posted by newhaul
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Interesting, and new to me.
S type* hot gas aerosol fire fighting systems ➥ https://www.scielo.br/j/bjce/a/7xD6X...zK8pm/?lang=en
* Strontium nitrate based
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"
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07-11-2024, 10:20
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#82
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Senior Cruiser

Join Date: Sep 2014
Location: puget sound washington
Boat: 1968 Islander bahama 24 hull 182, 1963 columbia 29 defender. hull # 60
Posts: 13,100
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Re: Unattended diesel heaters
Quote:
Originally Posted by Sailing55
And then there was the disaster of a friend of mine who routinely left his galley sink seacock open. A heavy snow, unable to get to the boat, weight of snow caused sink drain to become below new water line, 60' boat sank at the dock. All it takes is an unforseeable series of events. Also, routinely operating seacocks helps prevent failure. Again, just my opinion.
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Major difference between a cockpit drain and a sink drain . My sink drain has a check valve in it to prevent seawater intrusion when hard heeled on stbd tack
__________________
Non illigitamus carborundum
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07-11-2024, 10:26
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#83
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Senior Cruiser

Join Date: Sep 2014
Location: puget sound washington
Boat: 1968 Islander bahama 24 hull 182, 1963 columbia 29 defender. hull # 60
Posts: 13,100
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Re: Unattended diesel heaters
Quote:
Originally Posted by GordMay
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Fairly new to me as well a supplier of fire suppression systems I use told me about this and it makes sense for all boats engine spaces .
Cheap insurance you hope to never need.
I also recomend customers get a fire blanket for their galleys.
https://www.amazon.com/dp/B0CNYYQNDJ...fed_asin_title
Again cheap 8nsurance.
__________________
Non illigitamus carborundum
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07-11-2024, 10:39
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#84
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Registered User
Join Date: Sep 2015
Location: PNW Puget Sound
Boat: 1955 G L Watson 40' Yawl
Posts: 417
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Re: Unattended diesel heaters
Quote:
Originally Posted by newhaul
Major difference between a cockpit drain and a sink drain . My sink drain has a check valve in it to prevent seawater intrusion when hard heeled on stbd tack
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There seem to be many folks that advocate leaving seacocks open.
Also, check valves are easily defeated by a small piece of debris. Which, of course, is why they are not recommended to be used in bilge pump hose.
And, yes I know that this is thread drift.
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