Initial thoughts on rigs

For some time now, I have considered which rig to buy. Here are my current thoughts and decisions on a rig for the new boat.

 

Masts

There are 3 tubes and one slotted design to choose from as far as I am aware. Sailsetc groovy and tube, Housemartin tube and Pierre Gonnet tube. I currently have Housemartin spars and sails and am very pleased with their performance. I bought an A, B and C rig kit last year and they were all competitive however I read that the PG masts are lighter with similar flexibility and having sailed yachts, know that weight aloft can make all the difference in a chop, so I am going to try some and compare weights and stiffness and see how they perform. After a chat with Potter Solutions, we decided that 15mm or less is the optimum pre-bend for the A rig. Any more and you can easily distort the spar by compressing the mast as you take out the prebend with the back stay, as well as introduce uncontrolled bend between the spreaders and hounds and introducing too much tension in light weather. I must admit I have always suffered from a little bit of luff starvation just below the hound and wondered if this was caused by the pre-bend.

 

Booms

I choose lightweight jib booms (Easton arrow shaft - 2515. 25/64ths inch diameter, 15 thousandths of an inch wall thickness) from Sailsetc having used one before and will use off cuts of the mast for main boom and reuse my current goosenecks and fittings. Again the thought here is to go for the lightest section on the bow requiring the lightest counterweight.

 

Fittings

I use a roller bearing gooseneck for the A rig and standard gooseneck for B and C. I use aero-foiled spreaders but they are hung on wire so easily adjustable. Shrouds run through a hole in the front of the mast with a bowsie stopper inside. I use a sailsetc cunningham ring on all spars as my Housemartin sails have both luff tension and cunningham eye. 

 

Sails

As I mentioned above, I use Housemartin sails and have just bought a new A set for this year. Competition wise I see that BG and Sailboat RC (current world champions) with their moulded sail seem to be the sails of choice for championships but that could just be the sailors who use them. Thankfully I see members at Emsworth who have both sails so will be able to make a good comparison between all three. Of course there are several other sailmakers but these are the three World championship winning brands that have caught my eye from the available data at the moment, however I am new to the game and have probably missed lots.

 

What's the best package overall

Current observation suggests a SailboatRC package as they have won the last two worlds and dominated other events but Britpop with the BG rig have dominated in numbers and successes since 2011. Who will dominate at the Worlds in Croatia next year?

 

SailboatRC are pioneered moulded sails and now have a tried and tested design and who knows what else they have on the cards. I look forward to see how other sail designers and builders respond.

Jib Geometry. It's all in the geometry.

How many of you have the problem of the jib boom flicking out one side or the other in calm conditions, making it impossible to sail. I have encountered this problem since I launched my first boat boat. It was only in a discussion with Dave Potter last week that I found the solution. It's all in the geometry. See the picture below.

The diagram on the right has two diagrams.  The left shows the configuration I used last year. My leech line had caught around the spreaders a few times I thought it best to use a line and tie it forward at the head of the jib not realising that this impacts the geometry and caused the boom to kick out one way or the other when there is little or no wind.

If you want to see this in action, set the headsail up loosen your current leech line and tie a loose leach line onto the end of the jib boom. Make sure the line is long enough to reach the entry point on the mast. Put the luff and leach line under some tension. First move the top of the leech line to the right of the mast (i.e. aft) by an inch or so as set up in the picture and you should see the jib boom pull into the centreline of the boat. Now move the leech line in the opposite direction, forward of the mast and you should see the jib boom move as far away from the centreline as it can.

 

Talking to Dave Potter, he told me that he and Deve Creed solved the problem by tying the jib luff and leech line to a self tapping screw thus ensuring the leech line and jib luff tension line intersect the mast at exactly the same point allowing the jib boom to rotate freely in any direction

 

I pondered this for a while and came up with another solution using wire and a bowsie. The wire leech line and jib luff eye are attached to a bowsie inside the mast. They exit the mast and the jib luff can be hooked onto an eye fashioned out of the wire. Both enter the mast at the same point setting up the correct geometry.

 

Fingers crossed this will mean the jib boom will swing easily from one side to the other in calm conditions. I will let you know at the end of the week if it works

More thoughts on rigs

Key to the setup is to get the mast bend to match the main luff curve. If you read articles by Brad Gibson on tuning and see the latest interviews with New York Central Park MYC then you will hear how precise his setup is.

 

1 There is no heavy use of the Cunningham

2 His sails are very smooth

3 The main foot is set at the same depth for all conditions

4 The backstay will be adjusted by 2 to 4 mm only through the range of conditions.

5 He follows his own measurements for starting setup.

 

The key message here is to have a fixed setup. BG has been at this game for a long time and knows a precise setup to go fast. We can short cut the experience learning by following the setup notes on his web site or from the designer of whatever boat you sail. The Kantun has a similar set of setup numbers and instructions from the designer that are delivered with their boats. Other designers have done similar.

 

Remember if when your boat is on its side, you have trouble with hard spots on the luff of the main that have to be removed by excessive Cunningham, then you will need to tweak the variables available to you to get rid of the hard spots. They are:

 

The mast is upright

Spreader angle (and check they are symmetric, i.e. your mast hasn't rotated)

Mast ram

Shroud tension

Soften or harden the prebend

 

If you are still having a problem, check the mast is straight up to the point of prebend, your prebend is progressive rather than a sudden bend.

 

Of course, if your sails are old, they may have stretched and it will be hard to achieve a perfect result.

 

I will show you my setup below. I will have a PG rig from Potter Solutions with Housemartin sails. The settings are from you know where.

 

You might get the impression at this point that I am a BG fan. It is because he has pulled together all the relevant setup information on his website and it is the best I have seen in my travels across the internet but similar to Kantun. He also has the closest design to a BritPOP available (Alternative) for home build which I have.

For those interested in mast weight differences, there is a 20 gm difference between the Housemartin and the PG spar. I have heard that Sailsetc sparscome somewhere in between. The weights were 99 and 79gms. I haven't done a measurement on stiffness but I am sure someone out there has. They both feel pretty good. The prebend is 15 mm over 600mm on the A rig and 40mm on the B rig with one on the C rig.

 

The A and B rig arrived with with a clear mark on each showing the exact point where the prebend started. After marking up using the dimensions from the boat plan, I laid the mast on a long table. Use a couple of pink block from sailsetc (see picture) or something similar to make sure the holes are in the correct position. To start, I fitted one of the pink blocks and aligned the mast so the prebend was exactly vertical off the table. I could then drill the forestay hole and align every thing to that knowing that each hole would be aligned fore and aft or perpendicular in the case of the spreaders.

The gooseneck is glued on with superglue before drilling and fixing with a coupe of squares of deck patch material under the bottom of the gooseneck.

 

The boom just needs drilling in the same manner as above.

 

Using the pink drill blocks to align the pre bend with holes for the jib, shrouds, spreaders and gooseneck.

Thought for the day - Finish the rigs

All that is left is to cut the mast at the right length, fit to the boat, add the backstay and jib and then finish off the ends of the shrouds.

 

To cut the mast to the right length, I used a dummy tube inserted into the mast hole and marked off the lower and upper deck levels and the position where I wanted the gooseneck and the lower limit band. This must be no less than 60mm above the lower deck level but on the Alternative it is approx 74mm. Then I just measure down from the lower limit on the actual mast to the bottom with the dummy mast and cut.

 

Super glued the mast head and heel fitting (once the mast had been cut to the right length) so they would not move. Then I put the mast in the boat, attached the jib and the backstay and set the mast up straight to the rake on the plan. After, I attached the fittings on the ends of the shrouds and fixed the rigging screws to the boat. The rig was tensioned lightly so the main can be fitted and the rig tuned.

 

One last job is to find a way to stop the mast accidentally rotating. The advice is to use the gooseneck. Unfortunately the goosenecks I use don't quite lock the mast in place so I will have to find another solution.  I cut an inch of mast section and then  cut this in half and tape it onto the bottom of the mast with two thick cable ties to stop the taped on section compressing.  This way I lock the mast centrally and also push it forward slightly in the mast step which gives the boat better balance.

 

There are a few pictures of the completed B rig below

Note that I no longer use the cable tie as a jib pivot as they kept breaking so I have switched it for a Sailsetc boom clamp and attache the line to the boom with a sheet hook.  I am now in a position where I can raise and lower the jib boom..

 

 

36%20%60jib%20geometry_edited.jpg
35%20Jib%20head%20_edited.jpg
41%20drilling%20the%20mast_edited.jpg
40%20Spreaders_edited.jpg
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42 Mast head detail.jpg
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39%2C%20jib%20and%20leech%20line_edited.
47 Sail ties.jpg
41 Jib boom detail.jpg
50 Jib boom end detail.jpg
48 Jib head detail.jpg
49 jib tack detail.jpg
45 Making shroud terminations.jpg
44 Correctors and mast weights.jpg
The c rig correctors .jpg