The idea of raking Tammy Norie’s mast forward first came up when I compared Tammy to Fantail several years ago. As far as I can make out, raking Tammy’s mast will have three advantages:
- It will help the sail stay out in very light winds — particularly useful when becalmed.
- It will cause me to rebuild Tammy’s mast step, which is a known weak point.
- It will shift the centre of effort of the sail forward, improving the balance of the boat and reducing weather helm.
I believe I can achieve about 5° forward rake by moving the mast step aft, pivoting the mast within the cone that forms the partners.
This should being the centre of effort of the sail (shown below) forward by about 3.5m × 10cm/118cm = 30cm.
Firstly, here’s s picture of the existing step. I hope you can see why this is inadequate. It’s been replaced on every other Coromandel I’ve seen!
Here’s a drawing of the mast step that will make raking possible. I’m afraid I’m writing blog articles on my phone recently and so I don’t have my nice diagram software. You will have to make do with a photo of my pencil drawing.
This is basically a rectangular box made of aluminium angle, into which the mast is wedged using hard rubber chocks, and further secured with a retaining pin (to stop the mast wandering or jumping out).
The box is screwed to the laminated wood block that’s already glassed into Tammy’s hull, using large coach screws (hex heads and wood threads).
The mast base can be chocked and pinned at various positions in the box, allowing various angles of rake. Of course this means adjusting the blocks in the mast cone, so it’s not something to do at sea. I tried that (accidentally) once.
To allow for this I need to enlarge the hole in the berth that the mast passes through, making it into a round-ended slot.
Incidentally, the reason that the angle turns inwards is that it’s very hard to get tool access to this area of the boat. I don’t think I will be able to make pilot holes for the coach screws except through the slot for the mast. Having the screws inside also makes them possible to inspect through that same slot.
I hope this will all become a lot clearer when I start doing the work and have some photographs.
In the meantime, is be very interested in criticism or ideas for improvement.