In preparation for sailing the Western Isles of Scotland this summer, Ara’ Deg has now been fitted with a new mainmast at Lawrenny Wales after sailing her back from Cork Ireland last month.
Last trip with broken mast / jury rig across the Celtic Sea back to Wales clip below.
The replacement mainmast is a 45 foot galvanized steel tube 268 mm diameter at its base narrowing to 76 mm at the top.
I had ordered a 4 mm wall thickness weighing in at an estimated 220 kg but at the last minute the the company informed me that this was no longer available and only a 6 mm wall thickness pole weighing 350 kg (estimated) was available. After sleeping on it I decided to give it a go, partly because I felt committed to sailing north this summer (and to turn it down would likely mean scrapping that plan) and also the fact that a weightier mast would bring increased dynamic stability and more sea-kindly motion (see: kastenmarine.com/beam_vs_ballast for a more in depth discussion of weight distribution and stability).
For number crunchers, here’s the specs:
- Overall displacement (with mast) – 17,750 lbs / 8,050 kg
- ballast – 6,500 / 2,950 kg
- ballast to overall displacement ratio 38%
- main mast weight – 775 lbs / 350 kg (estimated)
- main mast to overall displacement ratio – 4.4%
- main mast to ballast ratio – 12%
- mainmast centre of gravity – 18 feet from base or around 14 feet above central roll pivot.
The mast has been painted white with a bright orange top for increased visibility and a navigation and anchor light fitted to the top. Moving spirit behind the up-and-coming Scottish expedition is Alison, who has been helping me prepare and step the new mast and rigging.
The proof is in the pudding as they say and when the main sail is rigged I’ll take her for sea trials to see how she handles. If it turns out to be too tender (i.e. heels too much given the strength of wind / sail area) then I will have to sail it with reduced sail until remedied. The remedies would be either replace the mast for a lighter one or increase the ballast. The latter solution would be preferred as it would be simpler, cheaper, and result in a more dynamically stable and sea-kindlier boat.
Of course I’m hoping it’ll be ‘just right’, without modification and it’ll be ‘full speed ahead’ for the west coast of Scotland.