Mast Rake Confusion II

When I first got my Solo (a 2005 all-wood Boon) one of the first articles I wrote in this blog was called Mast Rake Confusion as I didn't like and couldn't make sense of the way Solo masts were set up. I figured that as I got to know the boat better I would learn why the mast is raked back as far as it is. But I have to admit, that hasn't happened.

I sail every week in quite a big club fleet - we sometimes get ten+ Solos out and normally get six or seven. I have plenty of different boats to sail against ranging from the newer Winders, an FRP Boon, Ovingtons, Boatyard-At-Beer and some older wooden boats. And the sails used include Edge, P&B, North, HD and Batt. Frensham has produced a Solo National Champion in the past and the standard of sailors in the fleet is pretty high. The only thing I would say is they don't seem to travel to other clubs/events very much, with the possible exception of Simon Law who went to the Nationals last year.

So I have some good boats to test my speed against every week.

My boat came with Selden and Harken fittings as per the Steve Boon standard of 2005. My Selden mast step has a bolt across near the rear end of it to anchor various controls (kicker/cunningham etc). In front of it is where the mast foot goes.

I discovered there are three possible places the mast foot can go, based on the position of the bolts (one bolt goes behind the mast foot and one in front of it). When I got the boat, the mast foot was in the most forward position and this seems to be the recommended place based on the North Tuning Guide and the P&B Tuning Guide.

Last winter I sent the boat away to be re-varnished and when it came back I had to put the mast back on. As I was not sure I had the right setup, I experimented with it while the boat was in my drive.

My mast setup objectives:

• neutral helm when sailing the boat flat
• the mast approx upright (not leaning forward or back)
• mast near the back of the mast gate when the kicker is off
• if possible, good speed downwind as well as upwind

I wanted the mast as upright as possible and at the back of the mast gate (when no rig tension) so it could bend forwards a bit when I pull the kicker on upwind. To my surprise, I found the mast was approximately upright and against the rear of the mast gate when the mast foot was in the furthest back of the three positions.

NB If you haven't noticed this (and I didn't at first) when you pull the kicker on the mast moves forwards in the mast gate (because you are bending it) until it is stopped by the front of the mast gate or any mast chocks you put in there. Once it hits the front of the mast gate/chock, if you apply more kicker the mast still bends a bit more, but I guess the bend is higher up. As most of the fullness and therefore power is in the bottom half of the sail, bending the mast lower down reduces the sail power by making it flatter and helps you point a bit higher by flattening the curve of the sail just behind the mast.

This mast foot position worried me. It is about as far from the recommended place as you can get. The North guide says 3065mm from the front of the mast to the outside of the transom and the P&B guide says 3060mm. For my boat, either of those would mean putting the mast foot as far forward in the track as possible, not as far back

I measured my new mast foot position as 3036mm. My Cumulus mast is 70.5mm front to back, a couple of mm less than the Selden D+. So if I had a D+ (or a Superspars M2 - very similar) it might be a mm more but I am not sure my tape measure is accurate down to a mm. The Rooster spec for the Selden mast track says the bolt holes are 13.2mm apart so the recommended North/P&B position is almost exactly two positions further forward in the track on my boat than my mast is.

I set my forestay up so that the mast would only just touch the back of the mast gate. I did not follow the recommendation from North/P&B who say (I am massively summarising their advice) that you should let the forestay go (as in looser) two more holes than this (depending on conditions).

I set the shrouds so that the mast could be pushed forwards to about halfway along the gate. The advice on this differs a bit but it seems both P&B and North suggest letting the mast go even further forward in the gate.

So what difference does all this make?

I am currently sailing with my secondhand North P2, which is noticeably quicker than my 15-year old Dacron sails of last year, but a very similar sail to the boats I am racing against. With the new mast setup, I am clearly quick upwind - quite a lot quicker than those around me. Downwind I am about the same as those around me. A bit of a surprise? I thought the backwards mast rake was supposed to improve upwind performance - otherwise what is the point? Shouldn't I be slower than the others upwind?

With the 4mm chock I use at the moment, my old Cumulus mast bends nicely as I apply the kicker upwind and that is when it seems quickest.

NB You can easily make your own chocks from Acetal plastic offcuts found on eBay - the Acetal comes in a variety of thicknesses.

My fellow sailors frequently complain that the boom is low and difficult to get under when tacking/gybing and the Solo Assoc has just passed a rule to allow a "sail flattener" which as far as I can tell is a reefing point a short distance up the leach to allow you to raise the boom a bit. None of that is a problem with my setup.

So I will sail like this the rest of the year and see what happens - and post an update when I have more experience sailing in different conditions/waters. ⛵