A question of ballast

[PeterWillis]

A reader writes:
I have been totally restoring Rosanna (ex Glee) a one off designed gaff rigged yawl over the past 3 years. She was originally cutter rigged but sailed and re-designed, (through too much weather helm), by Maurice Griffiths who was a friend of a previous owner Edward Morgan (a true gentleman who has helped me with information since she came to me). We will be launching her later this summer.

I have been trying to source information to re-arrange her ballast (which has been 1 ton internal,cast iron pigs of 1/2 cwt each). I have had it in mind to cast lead shoes, to attatch to the 6x4 inchx17 foot cast iron long keel (individual shoes to make both casting and handling easier),say of 3/4 ton, and 1/4 ton to go internal for trimming.

Does this sound feasable and how should I attatch the shoes externally and the pigs internally?

Rosanna was built by Eversons of Woodbridge in 1960, she is 29ft lod 24ft lwl 41ft loa inc bowsprit and bumkin,& 4ft draught. She was built by eye, no plans available, and has a plumb stem and elegant counter. She is carvel built of 7/8 mahoghany on 1 1/4 sq steam bent oak timbers copper nailed and roved.She is very full forward of amidships at the turn of the bilge, and is almost flat bottomed through this section. Would you have any suggestions as to my thoughts on this matter?

 

[Guest]

Hello Peter,

Hope you are well.

I don't believe it is wise to switch from internal to external ballast as the boat might start to handle very differently. Too much external ballast and she could become quite rolly. I understand that there were no initial designs for this boat but I am certain that the re-designer Maurice Griffiths and the builder will have specified how ballast should be distributed.

Changing to lead would be a major advantage both from the cleanliness point of view and it would take up much less space of course.

It is one of the jobs I have still to do on Lady Ailsa but one which justifies structured procrastination perfectly.

With best wishes,

Vincent

 

[Mirelle]

Such things have certainly been done. When my sister bought White Moth she had this arrangement. However, I would think that changing the external ballast keel to a lead one would be even better.

 

[Peterduck]

It sounds as though the actual mass of the ballast is adequate; it just needs to be relocated longitudinally to adjust the position of the centre of gravity. I would suggest getting two or three of the internal pigs cast in lead and replace the ones at the lighter end. If the boat settles too deeply, remove pigs from the heavier end until she rides correctly. I have read in the past of quite small adustments making a very significant change to the behavior of a boat.
Swallow's ballast is all lead and all internal. Her keel is two Jarrah logs, each about 10" square in section and about 25ft long, mounted one above the other and bolted through. When I first owned her and was a lot greener than I am now, I had this "great" idea that I would replace the middle of the lower log with the lead from the inside, cast into a single piece of appropriate dimensions. My mentor, boatbuilder Tom Whitfield, cautioned me that the wringing strains on the keel imposed by the external lead would be too much for the rest of the centreline structure, and that I would never stop the garboards from leaking. What I have since realised for myself is that there would have also been a significant loss of longitudianl strength.
Hence the recommendation to leave the ballast keel alone, but just to make changes to the internal ballast. The Americans call it "Trimming Ballast" for good reason.
Peter.