I'm proposing horizontal rings (loops) of unidirectional fibre cloth (glass or carbon) around the circumference of the mast so the fibres run perpendicular the to length of the mast (the vertical). It is very important that you understand this correctly. Having the fibres aligned along the vertical will screw up the bending characteristics. The perpendicular (horizontal) loops will hardly affect bending.

Personal I would just make a sleeve on the inside and glue both parts to it and laminate the outside. I'm not the experienced guy in this aspect but I guess steaming some ply into shape will go a long way to make the sleeve. You will have to cut out the damaged ends and insert an new section here.

Most easy method I can think up (but I'm not the most experienced at this) would be to find some 1 mm thick ply steam the first one and bend it into the end of the mastsection. Then add more layers of 1 mm ply by bending it over the first one (steaming) and glueing them into place. This way you can build up any thickness of wall by adding layers. After the first 2 or 3 layers have been glued the insert will have been locked into shape. I would then take out the insert and glue some more layers on the inside finshing it off with some glass or carbon laminate. Maybe glue a web in there as well. Then I would glue the insert in to the mast sections (both ends) and then build up the part of the section that is replacing of cut off parts by adding more layers of ply or when it is already thick enough, adding layers of glass.

A way of making a poors mans scarve is to have the additional layers of ply on the inside reach up less far inside to old mast sections then the previous ones. This way you get a starecase like scarf. Of course this whole approach rest on using thin ply sheets and being able to steam them properly into shape. I heard from Phill that such sheets can be shaped with a blow drier as well. I would just test this and see of spraying some water before blow drying helps to shape these thigns

In the way of strength, we must not underestimate this composite of thin layers of ply. Before glass and other high tech fibres came along they used this veneer method to build life rafts. The advantages were, lightweight and yet strong construction and it would remain water tights and dependable even when stored for long times in dry places. This method was not used in a much wider sense (except for some race boats) as the labour involved for building a full boats was quite alot.


I will say one thing for the position of the damage. It is in quite a good place. The stresses and bending are pretty low on that spot. Meaning that you ca't really screw up on the repair or the bending of the mast. You have the liberty to induklge yourself in some "better save then sorry": reinforcements of the damaged area without worrying much about affecting overall behaviour of the repaired mast in the way of sailing.

I would just "risk" repairing it. And I'm not the most handy guy with laminates. Seems very doable for a reseanable handy person without the need to maintain tight margins. It seems like a rather cheap job as well. It is mostly labour. And you'll most likely end up with the right mast/sail combo again. Buying a new mast is an option you can always persue later when somehow everything fails.

Wouter