Author Topic: Ballast  (Read 4673 times)

Paul Thomas

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Re: Ballast
« Reply #15 on: September 09, 2015, 02:31:19 PM »
After observing photos of Partan sailing, she seems to sit a bit low at the stern.  Now it could be that I painted the waterline in the wrong place, but I think not, and anyway she looks perfect on a mooring.  There is also a  little weather helm that I would like to eliminate.  No doubt I could remove some weight from the aft lockers, but I have been considering adding a little removable ballast further forward to help the trim and reduce weather helm.  I have read all the posts so far with interest, and while there is a little nagging voice saying 'remove weight from the stern' I think this is the way ahead.  Is it possible that there is water in the bilge that runs aft when the crew board and forward when we go ashore?  The bilge pump is always dry. 

The question is where to put the extra ballast and what to use?  I don't want to increase the towing weight so water ballast would be handy, and I do want to improve the handling.  Should it be forward or aft of the mast?  As low as possible obviously, but would it be dangerous to replace foam with ballast?  Am I barking up the wrong tree?  Thoughts please anyone.

Mike Seller

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Re: Ballast
« Reply #16 on: September 10, 2015, 09:31:20 AM »
Hi Paul,

Your not alone! When on her mooring my boat sits perfectly on the water but with the added weight of an adult or two she tends to sink lower at the stern. This is aggravated by the heavy Yamaha outboard and stowing too many heavy objects in the lockers.
As you know all boats have a degree of weather helm and especially gaffers however it sounds as if you are struggling to keep a course without using some  force on the helm. I would avoid introducing additional ballast as this will alter the trailing weight etc. I would suggest (unless already tried) that you first go back to basics and try the following options. Take out the heavy items from the lockers ie anchor plus any chain etc and keep them below on the cabin sole when sailing. Sit further forward in the cockpit and maybe fit a tiller extension. Too much curvature in the mainsail will cause weather helm so play around with the outhall and the foot tension. Old sails stretch and with excessive curvature in the sail will slow the boat down as well.

Martin

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Re: Ballast
« Reply #17 on: September 10, 2015, 06:26:46 PM »
Hi Paul.

A huge subject I am afraid. But as Mike says, you are not alone!

I have experimented a great deal with the balance of the boat and have now removed all the ballast I added in previous years as I came to the conclusion you need so much to have any effect it becomes counter-productive.

I think you must separate the various issues, as although they are loosely connected, I have found it helps to deal with them separately.

1.   Stern digging in.
2.   Tenderness
3.   Weather helm

Digging in:- I think it is unlikely you have water in the bilges (you would notice this when you launch and recover). Your biggest weight in the back of the boat is the engine. I experimented with removing mine on occasions and it made very little difference to the sailing performance. However, it makes sense to move as much weight forward as possible. Easy wins are water tanks and anchor chain. There is no easy empirical way of measuring the boats ‘attitude’ but I would say that if you have water sloshing about on the cockpit floor something is wrong. I have quite a lot of weight aft and in stationary conditions (no waves or tide or heavy crew) the floor is dry although the water is right at the top edge of the engine well/cockpit floor.

I don't think it would be dangerous to replace the foam with ballast as I have always felt that the 'unsinkability' of the boat is rather academic. When are you going to be so far from help that it really matters?! However, as above, I don't think this will do you much good and will add to the towing weight. Personally I wouldn't go down the route of water ballast.


Tenderness:-  In my view (strictly non-scientific!) the standard topsail rig is too high and  there is not enough sail forward of the mast. It is the above-water weight which make the bigger difference rather than the below water weight. (Someone cleverer than me found that reducing the mast weight on a Corinthian OD by 18Kgs was equivalent to adding 50 Kgs of ballast to the keel).
Consequently, to reduce ‘tenderness’ I would lower the aspect ratio by ditching the topsail, and increase the size of the jib to increase the power. This will not help in light airs when you will be slower, (and not look as pretty) but you will find the bigger jib with a lower centre of gravity helps the tenderness issue considerably and aids the weather helm problem. Never reef your jib. Always reef your mainsail (even in quite modest winds).

Weather helm:- This is a function of wind strength. With a light boat like the Winklebrig you need to have flexibility of sails to match conditions. I sail very comfortably with Mizzen and Jib or Mizzen and Jib and staysail in almost all conditions. Fitting a Mizzen is a bit of a fiddle, but you could go a long way to help your weather helm by fitting a slightly longer bowsprit and a bigger (well cut) jib and then reef your mainsail frequently. The standard roller reefing system destroys the shape of the jib very quickly and I would ditch it in favour of a well cut sail and roller furling.

Finally, if you are only ever going to sail in sheltered waters and/or have a big moveable ballast in the way of one or two crew, don’t bother to make any changes.

Good luck!



David Bone

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Re: Ballast
« Reply #18 on: September 11, 2015, 05:10:29 PM »
Hello Paul,
To add a contrary and undoubted disputed opinion, here's my two pennyworth.

On obtaining WB107 in 2009, I found her unacceptably tender, with or without topsail and think the ballast/displacement ratio is too small.
In often prevalent gusty conditions, I frequently shipped water and gave myself some concern

To aid matters, the following amendments were made.

To reduce weight topsides:
1/ Hollow wooden mast fitted. Supplied by Noble Masts Bristol.  (I know you have the same on Partan.)
2/ Lightweight 42mm dia. aluminium topmast fitted in place of solid wood original.

To aid stability below:
1/ Approx. 80kg lead ballast fitted in cabin sole and in cool store/washbasin lockers under bunks.
   (Securely fixed but easily removable if required to reduce towing weight.)
2/ 22kg HD battery fitted under cabin threshold. (Step lengthened by 3" to allow both battery & portapotti stowage under.)

In my opinion, this has improved stability and sailing capability a whole lot.
I like to use the topsail in winds up to fc.3, as I find, that with tension on the topsail leech, together with a stainless horse extending across the stern, the gaff does not swing too far out, the sail shape is better and I can sail closer to the wind, without losing all speed.
Once the topsail has to come down, I usually find upwind performance disappointing.

Sometimes I sail on a friend's Winklebrig without added ballast, who never uses his topsail and even then it seems unduly tender and he often finds it necessary to reef down in quite moderate conditions.

Regarding trim, my boat lies slightly by the head at her mooring but once I park my 16 stone in the cockpit, even keel or slightly by the stern soon occurs.  I use a tiller extension, to normally sit well forward.
Nothing of weight is kept in the stern lockers, anchor and cable being kept on the foredeck or forward end of the cabin sole.
Except if there is a lot of wind, my passenger usually sits on a seat in the companionway, which keeps the weight fairly neutral.

I do carry some weather helm, with or without topsail, which I prefer but nothing excessive.

I do agree that a bigger jib sounds a good idea. Though I have on occasion been forced to reef the main, I have never found it necessary to reduce the jib.

Though I haven't sailed with same, I think the high peaked gaff is probably a much better setup than low peaked gaff and topsail.
Mike Seller provided me with dimensions and I intend to follow this course the comoing winter.
(Mike, I contacted Arun Sails, successors to Rockall and though they promised to get back to me, so far they haven't but we have a good local sailmaker, Goacher, who will knock me one up if necessary.)
I considering this, I am still debating whether to use the same length of boom as the low peeked gaff and add a mizzen, as used and recommended by Martin, or go with the standard high peaked setup with longer overhanging boom. (Probably the latter, as I am somewhat lazy.)
On this note, a friend with a WB has added a small mizzen to his own design, mounted right aft behind the transom, which he finds o.k. but when I was with him in light winds, experienced difficulty with the stern blowing round, when running with wind astern.

Martin now uses a balanced lug mainsail, to balance the mizzen by moving the centre of effort forward, which works fine for him.
I have a balanced lugsail on a Ness Boat, which is fine on its own but in my current fiddling to add a jib, even with an added bowsprit, I find that a jib and balanced lugsail just don't like sharing the same space.
Also, to stop the lugsail and spars dropping in a disorganised heap on the deck and crew, I find that lazy jacks, fwd and aft, increasing compilation, are needed to control the thing.

Regarding my extra lead ballast, I am so well pleased with this, that I will probably cut up the cabin sole and encapsulate the same weight of lead shot in resin within the space between inner lining and shell.
...................

Martin

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Re: Ballast
« Reply #19 on: September 12, 2015, 07:09:23 AM »
Hi Paul
I wouldn't disagree with anything David has said. It is all very sound advice. I was never brave enough to go the whole hog with ballast and I am sure 100Kgs plus would have a beneficial effect, if you can carry the extra weight on the trailer.

David is absolutely right about the uselessness of a mizzen with a following wind. A longer boom with a high peeked setup would make for  better sailing for all wind directions, but I like the ability to take down the main in stronger winds and bumble along in under foresails and mizzen.

David is also absolutely right about the balanced lug rig I have adopted. This modification is probably much  further than most people would want to go with a Winklebrig, but the luxury of being able to move the centre of effort forwards or backwards underway without affecting the shape of the sail has been a relevation to me. It is also wonderful to be able to raise and drop the sail with one rope.

I am not sure why, but there is no problem with the balanced lug mainsail sharing wind with the jibs (something to do with 'slots' I think) but the jib sheets do sometimes snagg on the boom when going about in light airs which is a pain. 

All in all, I recognise a extremely  accomplished sailor behind  David's writing and his seems very sound advice to me. I might even give the ballast another try!

Gwilym

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Re: Ballast
« Reply #20 on: December 28, 2015, 11:06:26 PM »
I am taking 65k of lead down to Constance tomorrow as I have found with just me on board there is not enough weight. In gusty winds it is very difficult to get the balance of reefing right I always seem to have to little or too much sail. I am hoping the lead forward on the cabin floor will make an improvement.

David Bone

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Re: Ballast
« Reply #21 on: May 25, 2016, 06:10:55 AM »
There are differing opinions about added ballast but I find it very beneficial. This winter, after experimenting for several years with quantity and location, I decided to fit lead shot encapsulated in epoxy, as low as possible, under the cabin sole.
60kg of shot was accommodated, at a SG of approx. 8.2.

The inner lining was cut out using a multi-tool, to within 35mm of the sides, 50mm from the forward end and aft to near the companionway.  Foam buoyancy underneath was scraped out and the inner hull cleaned.
(The black circle identifies a drain hole with plastic hose, cast in the keel ballast leading to the aft bilge well, fitted on build.)

Plywood floors were epoxied in place, to stiffen and subdivide the space, also create small collection well over the drain.
After coating the inner hull with International Danboline, drain channel of half 20mm plastic conduit were fitted as shown, secured with sealant.

To prevent the lead ballast sticking to the shell and floors, these were covered in polythene sheet and parcel tape.
Hopefully, this should allow the ballast to be prised out in future, if necessary.

Lead shot was mixed with West Epoxy into a thick slurry in a bucket and poured into each bay in turn, levelled with the top surface of the inner lining.  (400ml of epoxy mixed 7.5kg of lead shot.)
Initially I tried putting some dry shot in the first bay, then adding epoxy, mistakingly thinking it would soak around and mix with the shot. This didn't work well at all.

On completion, the cabin sole was covered by a sheet of epoxy coated and painted 12mm ply, fastened in place to the perimeter of the inner lining using stainless, self tapping screws, with small access hatch above the bilge well.

Additionally, approx. 20kg of removable,boxed lead sheet is secured in the after, under bunk storage wells, making 80kg in a all.  Finally, a 22kg H.D. battery is sited under the step aft of the companionway.

(The boat does still float and sails quite well.)

David Bone

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Re: Ballast
« Reply #22 on: June 05, 2016, 05:43:19 PM »
Consequent to my previous entry re consolidation of 60kg lead ballast under the cabin sole:
Last week I enjoyed two sustained sails, one with force 3, under topsail and one at force 5, without topsail.
I really felt that with this latest adjustment everything came together well. The boat was light on the helm, tacked quickly, handled gusts well and dare I say it, surprised me both with her 'speed' and ability to close the wind.
Together with the incorporation of a drop plate rudder and other amendments, including, thanks to Martin Cartwright's lead, (Inner forestay, two mast bands, extra shrouds and internal mast compression post.) I consider to now have a robust, well handling little boat of character.
Next step is fitting a high peaked gaff mainsail and later perhaps a larger jib.
Goacher Sails of Bowness have made a mainsail based on Mike Seller's high peaked sail. (WB95)
It now needs me to fashion a longer yard and boom, which given my usual rate of progress, will probably take till next year.

A couple of weeks ago, I was with sailing friends on the shore of Windermere, one of whom has an imaginatively improved, often used Winklebrig, (WB69) on a mooring. Discussing various boats, asked what he would really like. His answer: 'I am very content with what I have,' says a lot.
 

Martin

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Re: Ballast
« Reply #23 on: June 05, 2016, 07:00:15 PM »
Well done David!
That looks a really professional job and I have no doubt it will pay dividends in terms of stability and performance. You may need a new trailer though!!

Paul Thomas

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Re: Ballast
« Reply #24 on: September 20, 2016, 11:47:55 AM »
David,  It was good to see you, albeit briefly at Coniston in August.  You will be amused to hear that I lost my anchor while there.  I will email you with the location in case you fancy fishing for it.

I have been following your modifications with interest and thoroughly approve of them all.  I think your decisions are vindicated by their obvious success.

Regarding the new high peaked mainsail.  I have read recently that this can cause problems with the gaff saddle twisting once the angle of the gaff exceeds 45 degrees.  Using the original saddle may lead to problems with angle of the halyard stirrup and when you bend on the sail.  The article is by classicmarine.co.uk and I will email you the link.

Paul Thomas