Help me spec a new rig

Snowden

Super Anarchist
1,099
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IMG_1003.jpeg

 
A

Amati

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You had said up thread that the chain plates were redone with a naval architect involved- did you have access to stuff like righting moments etc?  Original plans?  Any differences from there as far as current DH & SH set up goes?  I got into this thread late, so if I missed something above, please point me to it.... anyway, interested to understand structural trade offs between things like rail meat vs no rail meat, losing control short handed, type of lift distribution, sail planforms....

 
A

Amati

Guest
Sadly not until late May - Selden are apparently as busy as they have ever been. Interestingly, they are working on the rig for the new Farr X2 in parallel and we are piggybacking on some of the ideas that have gone into that. They are making a carbon version of their rodkicker... let's see but I can always put the old Barton strut back on.

Have ordered a new 3Di AP jib from Norths though, 20.7 sqm reefing to 18 sqm with soft hanks. Slightly larger than the old #2, which was 19 sqm, but shorter luff enabled by the new longer J measurement and a small square top (apparently an IRC gain). Will pack the 2016 Nordac #3 (16 sqm) as a HW jib for Cat 3 racing. Need to think about Code Zeros, probably get the 2019 FR0 recut and ditch the Carl's Quantum MH0 or convert it into a garden ornament or something. We just moved house and the conservatory is becoming an oven in the sunshine :-D

For those that are interested, the IRC number went from 0.985 to 0.990 with +1.7 sqm HSA, no change in rig factor from the carbon mast (1.010) and no change in weight (TBC, added a battery, half a bulkhead and a floorboard so I think it's roughly flat but need to get her weighed when rigged). The tube weight saving should be (?) 1 kg / m and the mast plus boom is only 19 metres. Battery weighs about a ton or feels like it anyway. I think some of the standing rigging is down a size but not sure yet. We did take out the cathedrals.

Current projects are repainting some of the interior, tidying up electronics and figuring out deck gear layout. Bottom job (Durepox) is looking great.
FWIW, when we ditched our swept cathedrals, we lost a few points upwind, which was weird, with top runners on and off, 3/4’s rig though, no outs at that point above the 3/4’s hounds, 33 degree swept spreader rig.  Didn’t have quite the same leach control.  Put the cathedrals back on, with and without top  runners, got the points back.  Ballenger aluminum stick, tapered above the jib hounds. This was DH.

edit, no permanent backstay, just runners....

 
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Snowden

Super Anarchist
1,099
580
UK
You had said up thread that the chain plates were redone with a naval architect involved- did you have access to stuff like righting moments etc?  Original plans?
The chain plates were done by a previous owner (who himself was a naval architect) in about 2010. The boats were designed with inboard chainplates that tied into half bulkheads - all the boats (there are only 3 I think) had issues with the deck lifting. PO moved them to the gunwale and aft to 21 degree spreader sweep. By the looks of it he did a nice job, but I don't have copies of any Rm calcs if they were done at the time. 

Any differences from there as far as current DH & SH set up goes?
I have owned the boat for four seasons now and have played around with different jib areas and mainsail shapes. Goal was always moving the centre of effort aft to get some weather helm upwind and also lifting the bow downwind. Hence moving the mast 90 mm aft this year (18 degree sweep). I have generally increased jib size as despite her light displacement (2.7 tons) she needs the canvas to get moving in the light stuff as there's a lot of stern in the water plus a keel bulb. She's quite forgiving up the wind range as the construction is stiff enough to allow you to crank everything flat and depower. I think that will be less true with the new mast, as the old tapered alu stick was very bendy at the top, allowing you to twist off a lot of main.

 
A

Amati

Guest
The chain plates were done by a previous owner (who himself was a naval architect) in about 2010. The boats were designed with inboard chainplates that tied into half bulkheads - all the boats (there are only 3 I think) had issues with the deck lifting. PO moved them to the gunwale and aft to 21 degree spreader sweep. By the looks of it he did a nice job, but I don't have copies of any Rm calcs if they were done at the time. 

I have owned the boat for four seasons now and have played around with different jib areas and mainsail shapes. Goal was always moving the centre of effort aft to get some weather helm upwind and also lifting the bow downwind. Hence moving the mast 90 mm aft this year (18 degree sweep). I have generally increased jib size as despite her light displacement (2.7 tons) she needs the canvas to get moving in the light stuff as there's a lot of stern in the water plus a keel bulb. She's quite forgiving up the wind range as the construction is stiff enough to allow you to crank everything flat and depower. I think that will be less true with the new mast, as the old tapered alu stick was very bendy at the top, allowing you to twist off a lot of main.
With that much sweep, any sail design strategies to use/get around the main bring plastered all over the shrouds downwind?  (You’re using North?). Twist?  Camber?

 
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Snowden

Super Anarchist
1,099
580
UK
With that much sweep, any sail design strategies to use/get around the main bring plastered all over the shrouds downwind?  (You’re using North?). Twist?  Camber?
I opted not to replace the main until next season to manage costs a bit, so am using a 2016 Nordac sail made for the immediate previous owner. It has survived well despite being flogged a lot when flaking solo but is obviously more "draft aft" than it would have been new.

That main is made with a short E and max roach so you can really twist it if you want. What did help was getting several versions of the full-length top batten (which supports the roach) made in different thicknesses. I use a lighter one for light wind days to avoid sailing around with the top inverted and to get the right leech shape without excessive tension. Messing around with the main halyard / vang after the top mark & gybes to pop the batten is just another distraction short handed.

Downwind main trim <15 knots of breeze is a source of much beard stroking on board. I like sheet in + twist whereas my co-skipper prefers it nice and baggy against the shrouds. For better or for worse we didn't have many light wind days last season to collect data on which is faster.

 
A

Amati

Guest
^ I found that a shorter E and increased roach top has made a difference on my 1/2 tonner. In the windy San Francisco bay, it has proven to be quite effective. This next year - we will test the new set of sails, enhanced rig and setup against faster, newer boats. It really has become more of an endurance test of the crew rather than the boat. Not getting bashed and feeling beat up means we are more likely to finish.
It’s cool how more roach works better in higher winds.  More gradual feathering.  

 
A

Amati

Guest
I opted not to replace the main until next season to manage costs a bit, so am using a 2016 Nordac sail made for the immediate previous owner. It has survived well despite being flogged a lot when flaking solo but is obviously more "draft aft" than it would have been new.

That main is made with a short E and max roach so you can really twist it if you want. What did help was getting several versions of the full-length top batten (which supports the roach) made in different thicknesses. I use a lighter one for light wind days to avoid sailing around with the top inverted and to get the right leech shape without excessive tension. Messing around with the main halyard / vang after the top mark & gybes to pop the batten is just another distraction short handed.

Downwind main trim <15 knots of breeze is a source of much beard stroking on board. I like sheet in + twist whereas my co-skipper prefers it nice and baggy against the shrouds. For better or for worse we didn't have many light wind days last season to collect data on which is faster.
I grab the boom dinghy style and pull to weather 4-5 times in light airs.  Pop! (This is on a lightish 40er)  I have 3 different thickness battens for the top slot.  What works best for popping is using a top running back to grab the end of the top batten, & pull it to windward until it pops. The reason I asked the question is that there seem to be two extremes you can go with main twist - flat at the top with lots of twist built in, or more camber at the top, and less physical twist,  but if you have cathedrals limiting how far the top can fall off, which is better?  And if there are no swept spreaders on top, which might work better?  At least until you reef.  Has your sailmaker been any help with this conundrum?  That and changing the top batten all the time is a pain.

 
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Snowden

Super Anarchist
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580
UK
The reason I asked the question is that there seem to be two extremes you can go with main twist - flat at the top with lots of twist built in, or more camber at the top, and less physical twist,  but if you have cathedrals limiting how far the top can fall off, which is better?  And if there are no swept spreaders on top, which might work better?  At least until you reef.  Has your sailmaker been any help with this conundrum?  That and changing the top batten all the time is a pain.
Yes, see your point, will pick this up when it is time to replace the main. Current one is very much in the former camp, i.e. flat at the top. Getting beyond my knowledge level but intuitively it seems if the top is flatter than the bottom / midsection that would preserve a constant AoA when you put twist in it.

 

danstanford

Anarchist
674
175
Lake Ontario
Curious about the keel re-alignment. How far out was it and were you trying to solve a performance problem? 

There was a bunch of work done by a J/99 owner on problems of significant differences from port to starboard tacks and I wondered, after reading this if that might be a problem there? Last I read they centered up the top of the mast and it was much better but this prompted me to wonder. 

Dan 

 

Snowden

Super Anarchist
1,099
580
UK
Also, cautionary note for those that have replaced rigs or are considering it in the future - my insurers Pantaenius have a special "carbon rigs clause" which increases the Hull excess. The material change (was alu before) would have apparently voided the policy if I hadn't notified them.

 

MiddayGun

Super Anarchist
1,178
442
Yorkshire
Fingers crossed it's going in this coming Tuesday. We did get some sails though:
I feel your pain, Covid delayed the arrival of my new stick last year, didn't get it up an fitted until late June.

Got a program planned out this year for when you get it, or are you just playing by ear until its all setup?

 

Snowden

Super Anarchist
1,099
580
UK
A very interesting thread - thank you. I used to own a 762 and loved it. 
Cheers. Have never sailed a 762 but they look like great fun boats.

BTW if any other 920 / 762 owners are reading this I rebuilt the logo files in Illustrator with slightly improved kerning & can share:

Old

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New

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Any news on your rig?  

Delays have been all over the industry.  I am still waiting on sails that were ordered in Dec and scheduled for 1 May.  Made me switch my racing schedule to the West Coast on other boats.

 




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