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A few ventilation questions.


Doodlebug
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Hi all. Thinking about ventilation on the boat now its getting cold. I want as little ventilation as possible whilst staying safe.

 

According to the boat safety scheme.

 

The formula for calculating the fixed ventilation requirement ( in mm2 )is as follows:
= [2200 x U] + [650 x P] + [550 x H] + [440 x F], where:
U = input rating for all unflued appliances (inc. cookers) (in kW)
P = number of persons for which the accommodation space is designed
H = nominal output rating of all open-flued solid fuel appliances (in kW)
F = input rating for all open-flued appliances (in kW)
We have 1 cooker at 4kw
The alde is 4kw but I understand is not included in the calculation as it is a closed system.
2 people on the boat.
So I make the calculation:
=(2200×4)+(650×2)
For the cooker and two people.
That makes 10100mm2
There is a gap between the hatch and the boat. It is 8mm wide and 560mm long on both sides which is 9280
There is a mushroom vent at 5026mm2
So that seems like I have plenty of ventilation right?
Next question is if I did not have enough ventilation - and it was dangerous would I know? I'm talking about lack of oxygen and too much carbon dioxide. NOT Carbon Monoxide. We have 2 CO alarms but obviously that wouldn't help if I had too much CO2 or not enough O2.
Hope that makes sense!
Cheers
Doodlebug.
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Remember stove taking air out of boat needs replacing so where are your low level vents in equation ?

you can never have too much ventilation.

The heat from fire / heating should be more than adequate to not think about endangering life and build up of condensation by reducing ventilation .

Or do you plan to be one of this winters casualties .

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Maybe I wasn't clear. We have no solid fuel. A closed system alde and a hob only. So assuming the calculation is correct I won't be in danger. But if I was in danger I assume I would notice?

 

The diesel heater would be electric and the intake and exhaust would be external.

 

I want to minimise heat wastage. Burning loads of coal to heat the cold drafts seems silly to me.

 

Cheers

 

Doodle

Edit: Floor level? Surely the lowest possible is gunwales level?

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Taking a NB as an example - generally the front doors are in the 'well-deck' and the bottom of the doors are at floor level - there are normally vents in the bottom of the front doors.

 

Cruisers would no doubt have to have some system of getting air down to lower levels.

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As a recreational boater who leaves the boat on its tod for most of the winter, should I leave the windows open or shut to minimise condensation? I've always left them open (hopper type, so just open a couple of inces at the top) but one engineer told me to close everything up.

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Taking a NB as an example - generally the front doors are in the 'well-deck' and the bottom of the doors are at floor level - there are normally vents in the bottom of the front doors.

 

Cruisers would no doubt have to have some system of getting air down to lower levels.

 

Commercial vessels with accommodation below decks such as barges and tugs have ducts to low level from under the deckhead, cruisers would probably have something similar.

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As a recreational boater who leaves the boat on its tod for most of the winter, should I leave the windows open or shut to minimise condensation? I've always left them open (hopper type, so just open a couple of inces at the top) but one engineer told me to close everything up.

I do exactly the same, but I too would be interested in others' opinions. At my marina, some seem to do one thing, and some the other.

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Taking a NB as an example - generally the front doors are in the 'well-deck' and the bottom of the doors are at floor level - there are normally vents in the bottom of the front doors.

 

Cruisers would no doubt have to have some system of getting air down to lower levels.

The only ventilation in our cabin is through the two port lights and a roof hatch. All are closeable. It gets around the BSC requirements as it's a sea boat and they don't have to have any.

 

We do have to have a warning sticker on the hob though as a reminder to open a window!

 

We tend to leave the hatch cracked open and the port lights open even in the dead of winter and it stays warm and condensation free in the cabin.

Taking a NB as an example - generally the front doors are in the 'well-deck' and the bottom of the doors are at floor level - there are normally vents in the bottom of the front doors.

 

Cruisers would no doubt have to have some system of getting air down to lower levels.

The only ventilation in our cabin is through the two port lights and a roof hatch. All are closeable. It gets around the BSC requirements as it's a sea boat and they don't have to have any.

 

We do have to have a warning sticker on the hob though as a reminder to open a window!

 

We tend to leave the hatch cracked open and the port lights open even in the dead of winter and it stays warm and condensation free in the cabin.

Taking a NB as an example - generally the front doors are in the 'well-deck' and the bottom of the doors are at floor level - there are normally vents in the bottom of the front doors.

 

Cruisers would no doubt have to have some system of getting air down to lower levels.

The only ventilation in our cabin is through the two port lights and a roof hatch. All are closeable. It gets around the BSC requirements as it's a sea boat and they don't have to have any.

 

We do have to have a warning sticker on the hob though as a reminder to open a window!

 

We tend to leave the hatch cracked open and the port lights open even in the dead of winter and it stays warm and condensation free in the cabin.

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