Birchsorb damp absorber?

[sawduster]

I saw this recommended in a recent PBO article - has anyone used it and is it any good? BirchSorb Damp Absorber | BirchSorb

We are looking for something to use on a swinging mooring as the normal salt bucket type damp absorbers don't seem up to much.

 

[sarabande]

With all these 'damp-removing' devices you have to ask yourself how on earth the device empties itself when full of the moisture it has captured.

In this case, you might try weighing the packet when it is opened, and in due course when the "hyperdessicant" (What on earth is that ?) is full, weighing it again to see how much water it holds. Then your only choice is to replace it with another one at a fiver a go. or take it home and put it in the oven till it dries out, then reuse it.

Frankly I cannot see how a single sachet would last 8 weeks (their claim) on board in the 80 to 95% RH one experiences in the UK.

The only practical answer to high moisture content of cabin air on a mains-free mooring is to have lots and lots of natural ventilation, even to the extent of setting up a small computer fan and a dedicated battery topped up with a small solar panel. I have seen a keel stepped mast with a moderate hole about 100mm square near the base. The "stack effect" of a mast is really quite powerful at times.

 

[lustyd]

Water can’t be compressed and those are quite small. I’d go for the ones with a bowl to capture the liquid and a bit less marketing science. They may work, but I just can’t see them collecting enough before they’re full to be useful.

Worth a try on a mooring though as you don’t have many good options

 

[ash2020]

I seem to get more dampness when ashore over winter than I do on a swinging mooring. I'm trying a couple of those dessicant things this winter as our boatyard doesn't have leccy available.

 

[ash2020]

I seem to get more dampness when ashore over winter than I do on a swinging mooring. I'm trying a couple of those dessicant things this winter as our boatyard doesn't have leccy available.

 

[wingcommander]

I seem to get more dampness when ashore over winter than I do on a swinging mooring. I'm trying a couple of those dessicant things this winter as our boatyard doesn't have leccy available.

This makes sense as when on a mooring you swing to face wind or tide ( which ever is stronger) venting the boat . Leave a hatch or two open on vent . Cold air can't hold as much moisture as warmer air so naturally dryer

 

[lustyd]

Cold air can't hold as much moisture as warmer air so naturally dryer

This is so often repeated on here and is irrelevant. Warm or cold, you'll still get water condensing on your cold boat surfaces. Venting doesn't keep a boat dry, it keeps it less wet than doing nothing, but the boat will certainly still be damp.

 

[neil_s]

If you use damp absorbers you need to stop the ventilation. I use Kontrol crystals from Robert Dyas over Winter, but all the ventilators in the boat are taped over.

 

[LittleSister]

This is so often repeated on here and is irrelevant. Warm or cold, you'll still get water condensing on your cold boat surfaces. Venting doesn't keep a boat dry, it keeps it less wet than doing nothing, but the boat will certainly still be damp.

Venting a boat does keep it dry, because any condensation is soon absorbed again by the atmosphere once the temperature rises/humidity falls. A friend's very well vented boat was left (unprepared) for several years, due to unforeseen circumstances, in a mud berth in an East Coast creek. When we went aboard it was absolutely fine, dry and didn't smell in the slightest bit musty. (And that included the teacloth I'd put down damp on the side in the galley when I left the boat in a hurry after what turned out to be our last trip before it was 'abandoned'.)

It helps if the interior of the boat is clean of salt and grime.

 

[lustyd]

People with musty boats always say that! If it were true, caves would be dry, sweet smelling places. Nature will take over unless actively fought against, that's just the way the planet works.

 

[LittleSister]

People with musty boats always say that! If it were true . . .

I assure you it is absolutely true. (And I have certainly known musty boats, and parts thereof, with which to compare it.)

I can also advise that some caves actually are dry and sweet smelling. It will depend, among other things, on how well aerated they are (most have only one opening, which may be relatively small), whether there is water seeping into it through the rocks etc., and whether there is earth or other absorbent material to retain moisture.

 

[greeny]

For me, I either use a de hum. with good drain to let the water away and keep the boat sealed to allow the inside to be dry with no moisture in the air to condense on the cold hull. OR just get good ventilation and allow the air inside to be exactly the same humidity as the air outside and at the same temperature. Doesn't work 100% but certainly better than any compromise attempt that I often see. De -hum and windows left open for ventilation.

 

[wingcommander]

A bit like

For me, I either use a de hum. with good drain to let the water away and keep the boat sealed to allow the inside to be dry with no moisture in the air to condense on the cold hull. OR just get good ventilation and allow the air inside to be exactly the same humidity as the air outside and at the same temperature. Doesn't work 100% but certainly better than any compromise attempt that I often see. De -hum and windows left open for ventilation.

A bit like car windows open on a hot day ...and the air conditioning blasting away trying to cool the planet

 

[oldmanofthehills]

Dehumidifier and 100W solar panel. . Place dehumidifier above sink. When there is light the dehumidifier turn on. About £220 and perhaps not worth it but .....

Might even have enough capacity to keep main battery charged while cruising, but probably not while moored up for the winter. Add switch?

 

[lustyd]

Dehumidifier and 100W solar panel. . Place dehumidifier above sink. When there is light the dehumidifier turn on. About £220 and perhaps not worth it but .....

Might even have enough capacity to keep main battery charged while cruising, but probably not while moored up for the winter. Add switch?

How do you ensure it completes the shutdown routine to avoid a fire?

 

[oldmanofthehills]

How do you ensure it completes the shutdown routine to avoid a fire?

That price includes the controller that limits current and voltage to a battery so no problem when used to charge battery. I think a 12V car type battery unlikely to ever catch fire whatever you do, anyway

If driving dehumidifier it might give an over voltage at the dehumidifier unless it had a small battery. On shut down the dehumidifier wont take any current, so nothing to cause any fire. Open circuit voltage if no battery might be quite high but if no current, no heat output. Perhaps small worn out 12v battery best but you could try without

Smaller panels as I also have in van have no controller, it just gives 18v with no load and about 13V into battery.

I am unsure where you see the problem

 

[lustyd]

On shut down the dehumidifier wont take any current, so nothing to cause any fire.

Dehumidifiers need a cool down process and do use current. You can't just cut the power to them as they are hot and without the fan they can and do catch fire.

 

[AntarcticPilot]

This makes sense as when on a mooring you swing to face wind or tide ( which ever is stronger) venting the boat . Leave a hatch or two open on vent . Cold air can't hold as much moisture as warmer air so naturally dryer

Also, the boat will be warmer afloat than ashore. Water can't get colder than a degree or so below freezing; air can be considerably colder.

 

[Wansworth]

I used my “patent all weather gentlmeans forehatch cover”…….this enables the forehatch to be open but not for burgerlers and my new improved companion way sliding hatchboard with scientifically designed holes………Laid up nine months a year no damp at all……Alban Vega

 

[oldmanofthehills]

Dehumidifiers need a cool down process and do use current. You can't just cut the power to them as they are hot and without the fan they can and do catch fire.

Nonsense. Dehumidifiers are essential air fridges that work on a heat gradient. Large domestic ones have caused overheating at rear, as have fridges and have started fires. There is no advice to let cool down before turning unplugging ordinary domestic ones as the only cooling element is the running fan itself

The 12v dehumidifiers readily available are of low wattage and often run from USB outlets thus probably a max of 25W and less likely to catch fire than dim old style lighting in my heads as they are specifically designed to dissipate heat unlike my festoon bulb lighting - I certainly dont worry about my van coolbox which is similar technology and suggest mounting of a dumidifier in clear air above a drain where air flow is good and thus cooling good . They are also cheap at under £40 which is good for a trial experiment as the greatest cost would be the £110 solar panel which is itself a useful addition to a cruising boat