Adding water to hull for ballasting

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Ulsterman81
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Adding water to hull for ballasting

Post by Ulsterman81 » Tue Mar 06, 2018 5:58 pm

This question clearly identifies me as the newbie that I am and I apologise if it's a stupid one or if it's been addressed elsewhere.

With regards to ballasting my kayak - is adding water (via the hull drainage plug) the correct way or even a legitimate way of ballasting my Ocean Kayak Scrambler for rougher waters? I understand that weight towards the stern will help stop weathercocking. When water is added through the hull drainage plug, does it pool across the length of the keel to the stern?

Any help is appreciated.

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Re: Adding water to hull for ballasting

Post by simon64 » Tue Mar 06, 2018 6:20 pm

You will end up with a less stable kayak despite the extra ballast as the water will move around side to side.

Chris Bolton
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Re: Adding water to hull for ballasting

Post by Chris Bolton » Tue Mar 06, 2018 7:46 pm

Yes, the water will move around, both side to side and end to end. If you remember the Herald of Free Enterprise ferry that capsized, it was the water in the hull that caused the instability - look up "free surface effect". Generally, even solid ballast in a kayak isn't the best way to improve stability, as the extra weight makes it sluggish and harder to handle, and unless it's fixed in, it can move and then you're worse off - if you find you need ballast, practice on calmer water until your balance is better, or get a more stable design of kayak.

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Re: Adding water to hull for ballasting

Post by Bards » Tue Mar 06, 2018 9:43 pm

The only way I found of effective ballasting was placing weight along the internal centerline that couldn't move. Lead flashing from a scrapyard worked (I believe best sealed from a toxic point of view, but personally I was far too slovenly for that) as it's density allows for Centre of Gravity to be super low down buy the keel.
Whatever method of securing is used, it has to work when inverted so it doesn't drop to the deck if boat is inverted. That way it would become a keel weight working against righting the kayak - not what you need following a capsize! That's another of the big problems with loose water...

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Re: Adding water to hull for ballasting

Post by Northern Blue » Wed Mar 07, 2018 5:26 am

My Thresher 'sit on top ' was sometimes difficult to handle and would have benefited from having a rudder fitted.

Is this an option on the Scrambler ?

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Re: Adding water to hull for ballasting

Post by Bards » Wed Mar 07, 2018 10:32 am

Bards wrote:
Tue Mar 06, 2018 9:43 pm
The only way I found of effective ballasting was placing weight along the internal centerline that couldn't move. Lead flashing from a scrapyard worked (I believe best sealed from a toxic point of view, but personally I was far too slovenly for that) as it's density allows for Centre of Gravity to be super low down buy the keel.
Whatever method of securing is used, it has to work when inverted so it doesn't drop to the deck if boat is inverted. That way it would become a keel weight working against righting the kayak - not what you need following a capsize! That's another of the big problems with loose water...
Apologies - just noticed the boat is a SOT. Ignore my advice - not applicable to yours.

Bards

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Re: Adding water to hull for ballasting

Post by rockhopper » Wed Mar 07, 2018 1:41 pm

Is your problem stability or weather cocking?
The scrambler is a fairly stable SOT so I suspect it is weather cocking that is the issue. Ocean Kayak do sell rudder kits but they are very expensive (£300 +) and I don't think they fit the Scrambler.
Your best bet may be to replace the Scrambler with a different boat that comes with a rudder system fitted.

Rog.

Ulsterman81
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Re: Adding water to hull for ballasting

Post by Ulsterman81 » Wed Mar 07, 2018 8:03 pm

Northern Blue wrote:
Wed Mar 07, 2018 5:26 am
My Thresher 'sit on top ' was sometimes difficult to handle and would have benefited from having a rudder fitted.

Is this an option on the Scrambler ?
I'm not aware of any rudder option for the Scrambler.

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Re: Adding water to hull for ballasting

Post by PlymouthDamo » Wed Mar 07, 2018 9:05 pm

Ulsterman81 wrote:
Wed Mar 07, 2018 8:03 pm
I'm not aware of any rudder option for the Scrambler.
There's a consensus view that putting water inside your hull would be a bad idea. What is it that you're trying to overcome? E.g. (as rockhopper asked) are you having a problem being turned around by the wind? From my limited experience (on a smaller sit-on-top than yours) I found the handling wasn't problematic - it was a flat, stable platform that was short enough to turn fairly easily. On the downside, it was slow and ponderous. I can't imagine anyone trying to add extra ballast as this type of boat is so wide that you'd need an anvil on there to make a noticeable difference. I used mine to carry some very heavy diving gear, which definitely slowed it down but I don't recall any major change in the way it handled - it still felt like paddling the Ark Royal, when compared to a narrower sit-in boat.

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Re: Adding water to hull for ballasting

Post by Chris Bolton » Wed Mar 07, 2018 9:11 pm

Apologies, William, I didn't read your original post carefully enough; I was thinking stability was the issue not weathercocking. The reason for weathercocking is an inbalance between the centre of the side-on wind area and the centre of the side-on underwater area. So you are correct that you can reduce it by moving weight to the back, either by sitting further back (may not be possible) adding weight to the stern or moving weight from the bow stowage to the stern. Conversely, you can also reduce it by moving windage toward the bow, for example, an empty storage barrel in the front stowage, or just putting your light stuff in the bow and heavier stuff at the stern. But if you do that, make sure you can get at it to move it, as leecocking can be dangerous - you end up blown downwind and can't turn. Weathercocking also gets worse as the boat moves faster, because the bow wave increases the underwater area at the bow and takes off the same amount of wind area.

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Re: Adding water to hull for ballasting

Post by rockhopper » Thu Mar 08, 2018 1:24 pm

Also bear in mind that in some instances a rudder can make weathercocking worse as wind from the side will push the front end round whilst the rudder at the rear acts as a pivot point. As long as the rudder is easy to lift out of the water then it is easy to experiment and find out whether to have the rudder up or down for the circumstances you are paddling in.

Rog.

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Re: Adding water to hull for ballasting

Post by Ulsterman81 » Fri Mar 09, 2018 6:36 pm

PlymouthDamo wrote:
Wed Mar 07, 2018 9:05 pm
Ulsterman81 wrote:
Wed Mar 07, 2018 8:03 pm
I'm not aware of any rudder option for the Scrambler.
There's a consensus view that putting water inside your hull would be a bad idea. What is it that you're trying to overcome? E.g. (as rockhopper asked) are you having a problem being turned around by the wind? From my limited experience (on a smaller sit-on-top than yours) I found the handling wasn't problematic - it was a flat, stable platform that was short enough to turn fairly easily. On the downside, it was slow and ponderous. I can't imagine anyone trying to add extra ballast as this type of boat is so wide that you'd need an anvil on there to make a noticeable difference. I used mine to carry some very heavy diving gear, which definitely slowed it down but I don't recall any major change in the way it handled - it still felt like paddling the Ark Royal, when compared to a narrower sit-in boat.
I probably didn't make myself very clear. It's really more a case of weather cocking than instability. It's my first kayak so I have nothing to compare it to.

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Re: Adding water to hull for ballasting

Post by Ulsterman81 » Fri Mar 09, 2018 6:39 pm

Chris Bolton wrote:
Wed Mar 07, 2018 9:11 pm
Apologies, William, I didn't read your original post carefully enough; I was thinking stability was the issue not weathercocking. The reason for weathercocking is an inbalance between the centre of the side-on wind area and the centre of the side-on underwater area. So you are correct that you can reduce it by moving weight to the back, either by sitting further back (may not be possible) adding weight to the stern or moving weight from the bow stowage to the stern. Conversely, you can also reduce it by moving windage toward the bow, for example, an empty storage barrel in the front stowage, or just putting your light stuff in the bow and heavier stuff at the stern. But if you do that, make sure you can get at it to move it, as leecocking can be dangerous - you end up blown downwind and can't turn. Weathercocking also gets worse as the boat moves faster, because the bow wave increases the underwater area at the bow and takes off the same amount of wind area.
There is a lot more to consider than I realised. Thanks for the advice.

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Re: Adding water to hull for ballasting

Post by Ulsterman81 » Fri Mar 09, 2018 6:44 pm

rockhopper wrote:
Thu Mar 08, 2018 1:24 pm
Also bear in mind that in some instances a rudder can make weathercocking worse as wind from the side will push the front end round whilst the rudder at the rear acts as a pivot point. As long as the rudder is easy to lift out of the water then it is easy to experiment and find out whether to have the rudder up or down for the circumstances you are paddling in.

Rog.
Thanks Rog. I'm coming to the conclusion that my lack of experience may be the issue rather than lack of the correct equipment. I'm going to get more paddle time and experiment with moving weight from bow to stern.

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Re: Adding water to hull for ballasting

Post by TechnoEngineer » Wed Mar 21, 2018 8:40 pm

I've used water in plastic bottles. Whatever you use must be firmly fixed in place and if you use water in a bottle there must be very little air; you don't want a surface sloshing around.
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