Author Topic: Ballast  (Read 5813 times)

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Ballast
« on: April 08, 2014, 09:12:43 AM »

Martin_cartwright
Username: Martin_cartwright

Registered: 04-2008
   
Posted on Sunday, July 05, 2009 - 03:37 pm:      
I 'raced' in the Old Gaffers race off Southwold yesterday and to begin with (Force 2-3ish)Winkle performed very well keeping up with the rest of the fleet. Then the wind, sea and tide picked up and I was forced to retire as even fully reefed I was over canvassed and could not make any headway.I had a great sail under headsails and mizzen while I waited for the rest of the fleet to finish (although 3 hours in those conditions was about 2 hours too long!), and I am drawn to the conclusion that when sailing the Winklebrig single handed at sea, more balast is required. Possible solutions are:-
1. Adding to the weight of the centre boards.(Possibly a lead or iron shoe down each leading edge?).
2. Adding to the weight of the keel:- Some sort of shoe arrangement.
3. Adding internal balast:- Replacing some of the foam with concrete.

I know I could always try and recruit one or two large crew members, but I actually like single handed sailing. Anyone any (polite!) ideas?

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Re: Ballast
« Reply #1 on: April 08, 2014, 09:13:00 AM »
James_parsons
Username: James_parsons

Registered: 04-2009
   
Posted on Monday, July 06, 2009 - 10:36 pm:      
Couple of thoughts Martin: My boards came with steel shoe already in place, and at some stage someone has drilled holes and added lead as well. I think it's mainly to help keep them down, as the weight is still not great. I haven't done the maths, but with the short length of the boards I think you'd have to add so much ballast to make a decent difference to righting moment that you'd have a job hauling them up without a winch.
A question, which may be dumb - what sails were up when you were overcanvassed? I note yours is the WB with lots of extra sails! I sailed mine solo in up to F5 with 2nd reef in main and the foresail 3/4 rolled in, and managed to make to windward ok. I also had both bilge boards right down - increased drag and hefty weather helm, but she stuck in there and I had an exilarating sail. I guess the fact that mine is the high peaked gaff version must also help. The centre of pressure must be lower. I also had sore arms afterwards!

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Re: Ballast
« Reply #2 on: April 08, 2014, 09:13:21 AM »
Julian Swindell
Username: Julian_swindell

Registered: 03-2007
   
Posted on Tuesday, July 07, 2009 - 11:42 am:      
Hi Martin,
Be cautious. I think the golden rule is not to make significant changes to the designer's critical details, such as ballast ratios. He will have given hours (days) of thought to the correct figures. Don't change them on a whim. If you over ballast you may:
a) sink if you get swamped,
b) Break the rig if you force it to stay more upright in stronger wind than it was designed to take. The major safety feature of gaff rigs is that as they heel they spill wind.

I think you have also fitted a mizzen mast to your boat, which means even with the sails down, you are going to get some increase in weather helm because of the extra windage of the rear mast.

I would always say that if you are getting over powered in a Winkle Brig, get the sails down and head for home! This is not a foul weather, blue water boat.

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Re: Ballast
« Reply #3 on: April 08, 2014, 09:13:51 AM »

Martin_cartwright
Username: Martin_cartwright

Registered: 04-2008
   
Posted on Tuesday, July 07, 2009 - 08:47 pm:      
James and Julian thanks for your views.I know I have lots of extra sails but I had reduced down to the standard WB rig and then beyond to jib and mizzen!

I guess that you are right with your final para. Julian, but I had hoped that I could make a relatively small adjustment below the waterline to make up for the absence of a crew member above it, as I felt that Eric B. would have designed the boat for a crew of two or more.Perhaps if you are reading this Eric, we could have your views?

I think the mizzen does add to windage, but on this occasion, I wouldn't have got home without it (as I didn't have enough petrol for 3 hours motoring and had to wait outside the harbour for the tide to turn).

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Re: Ballast
« Reply #4 on: April 08, 2014, 09:14:06 AM »
Roger Parish
Username: Roger_parish

Registered: 03-2007
   
Posted on Thursday, July 09, 2009 - 04:47 pm:      
Have a look at the article by Moray McPhail in Water Craft Jan/Feb 2003. He points out that its always best to reduce weight above the boats centre of gravity rather than add extra ballast below to improve stability or carry extra sail. He replaced the wooden mast on his Corinthian OD with a carbon fibre spar. (25kg down to 7Kg!) This he calculates was equivalent to adding 50 kg of ballast at the keel to achieve the same lowering of the centre of gravity....and you haven't increased the weight to tow.

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Re: Ballast
« Reply #5 on: April 08, 2014, 09:16:58 AM »
Roger Parish
Username: Roger_parish

Registered: 03-2007
   
Posted on Thursday, July 09, 2009 - 04:47 pm:      
Have a look at the article by Moray McPhail in Water Craft Jan/Feb 2003. He points out that its always best to reduce weight above the boats centre of gravity rather than add extra ballast below to improve stability or carry extra sail. He replaced the wooden mast on his Corinthian OD with a carbon fibre spar. (25kg down to 7Kg!) This he calculates was equivalent to adding 50 kg of ballast at the keel to achieve the same lowering of the centre of gravity....and you haven't increased the weight to tow.

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Re: Ballast
« Reply #6 on: April 08, 2014, 09:17:27 AM »

Martin_cartwright
Username: Martin_cartwright

Registered: 04-2008
   
Posted on Thursday, July 09, 2009 - 05:57 pm:      
Thanks Roger. I hadn't thought of that. I don't really want any more weight out of the water!

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Re: Ballast
« Reply #7 on: April 08, 2014, 09:17:40 AM »

Adrian Evans
Username: Adrian_evans

Registered: 03-2007
   
Posted on Monday, July 13, 2009 - 05:38 pm:      
Before I bought Peggoty, one of the boats I looked at was #122 - the last built. In the extensive advert the then owner had put together, he mentioned that recent boats had had additional ballast, 50kg I think, added forward, in response to owners feedback.
Not sure exactly where or how though.

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Re: Ballast
« Reply #8 on: April 08, 2014, 09:18:01 AM »

Martin_cartwright
Username: Martin_cartwright

Registered: 04-2008
   
Posted on Friday, July 17, 2009 - 09:14 am:      
I have done a bit more research on this including speaking to Eric Bergvuist and a local boatyard. Probably only for academic interest this is a distillation of what I have discovered (from you guys as well as the professionals) :-

1.Adding weight to or fiddling with the centreboards is risky. The lateral pressure on the casing/hull is quite considerable anyway and anything which might increase this is unwise.

2.She is only a little boat. Don't expect too much from her. (Although I am currently reading a book about 'Shrimpy' an 18 footer which circumnavigated the globe in the 70's!).

3. Eric tells me that one of the prime design constraints at the time was the ability of a small family car to tow her. In these days of 4x4's these constraints have disappeared. Eric said that during testing of the boat he had to fill it with a very considerable weight and the water line changed hardly at all. Based on this he felt that a degree of ballasting wouldn't harm.

4.A stainless shoe the length of the keel filled with lead (I estimate about 100kgs total weight and probabley not more than 4" deep)and bolted through would work, but care would need to be taken drilling through the keel as it is made of iron embedded in resin.A timber or nylon plug would have to be bonded in first and then drilled.

5. The above would be prohibitively expensive!

6. The hull shape is not dissimilar to the old 'sandbaggers' - 19th century fishing vessels which used to fill their holds with sand bags which were emptied overboard as fish were caught -thereby maintaining ballast.I am going to experiment with sandbags.

7. Eric confirmed that it is a myth that some boats were made with heavier keels. Sorry Adrian!

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Re: Ballast
« Reply #9 on: April 08, 2014, 09:18:17 AM »
Barend Nieuwendijk
Username: Barend_nieuwendijk

Registered: 08-2008
   
Posted on Sunday, July 19, 2009 - 08:13 pm:      
Hi Martin,

Thanks for your research.
I am the present owner of WB 122 and indeed I was told when buying it that she had 50 kg extra ballast. Now I know better.
That is not so bad because I am planning to install an electric propulsion and will have extra weight because of the batteries.

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Re: Ballast
« Reply #10 on: April 08, 2014, 09:18:30 AM »

Martin_cartwright
Username: Martin_cartwright

Registered: 04-2008
   
Posted on Tuesday, July 21, 2009 - 02:36 pm:      
I think the installation of electric propulsion with a light motor at the back and a heavy battery nearer the centre of lateral resistance is an excellent solution. It raises the stern so there is not so much drag in the engine well, allows you to fill your aft lockers with heavier equipment and gives you a reasonable amount of ballast where you need it further forward. I would do the same only my petrol engine has to last a bit longer! What electric motor are you buying?

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Re: Ballast
« Reply #11 on: April 08, 2014, 09:18:45 AM »
Barend Nieuwendijk
Username: Barend_nieuwendijk

Registered: 08-2008
   
Posted on Tuesday, July 28, 2009 - 09:34 pm:      
Well, I am studying about it.
One possibility is the Torqeedo (it is a bit expensive, bur very innovative and powerful). In September the dealer will demonstrate me some models on a boat. I have read some reviews in which the authors mentioned that the Torqeedo is not as quiet as you wish. So I first have to see and hear it live.
My plan is to install the electric engine before the next season.

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Re: Ballast
« Reply #12 on: April 08, 2014, 09:19:04 AM »
David Cawston
Username: David_cawston

Registered: 03-2007
   
Posted on Thursday, July 30, 2009 - 05:13 pm:      
Hi Barend, If you search on youtube for torqeedo, there are several videos, on all the ones I have watched the torqeedo is very noisy and the electric boat association are of the same opinion. The Minn Kota Riptide motors are a great deal quieter (and a bit cheaper) but they are not as powerful as the torqeedo 801. Be careful regarding positioning the battery if it is a lead acid type and charged onboard, hydrogen gas given off! I would position the battery (or possibly two or three) underneath the V berth, cut a hole in the plywood, hack out the foam and the cables could be run underneath the bunks to the rear wells and through grommets to the motor. Three batteries and 36 volts are good for the Minn Kota Riptide 101. If your dealer has one of these Riptides, I would be very interested to hear how well it works on a WB.

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Re: Ballast
« Reply #13 on: April 08, 2014, 09:19:19 AM »
Martin_cartwright
Username: Martin_cartwright

Registered: 04-2008
   
Posted on Friday, July 31, 2009 - 04:33 pm:      
I don't know what size these batteries are, but you may find three lead acid batteries forward of the mast to be a bit too much weight too far forward (increased weather helm and weight to push off the trailer when launching). I am currently experimenting with 65kgs of lead ballast in the portapotti position. Will let you know how I get on.

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Re: Ballast
« Reply #14 on: April 08, 2014, 09:19:39 AM »
Martin_cartwright
Username: Martin_cartwright

Registered: 04-2008
   
Posted on Tuesday, September 01, 2009 - 02:41 pm:      
I went sailing at the weekend in some fairly blustery conditions and can report success with the ballast in terms of the boat's stability. I have now stowed 65kgs of lead along with 10m of anchor chain and two 10 gal water tanks where the portapotti used to go and the handling is greatly improved without any noticeable decrease in speed. Taking Roger's comments into consideration (about reducing weight above the centre of gravity) , I have detached the topsail from where I was stowing it (on the gaff) and I think this helps as well, although I have still to find an effective way of launching this single handed.
Two unexpected bonus':- The extra weight aft of the trailer's axle makes the nose weight less and it comes off the trailer more easily!