Roller furler and heavy weather jib under IRC

[Chris 249]

I'm looking for some feedback on the rating and performance issues of using a roller furler genoa and a heavy weather jib under IRC. The boat is a J/36, and our sister with the same setup rates a very low .981 despite having an outboard (!) and not a diesel. I'm not looking for a rule bandit, just to find out whether the rating cut will compensate for the performance cut.

We've just bought the boat, which has only cruising sails including a good quality jib furler. I don't really want to go down the route of having a full wardrobe; it's too expensive in cash, crew and in space down below in a boat that is largely for cruising. We also normally sail in a windy area where the other "big" boats are using 120-130% overlaps. Although normally I love short overlap headsails and I have concerns about the sheeting angle of 120-130% sail, I also appreciate the upwind light-air speed of the J/36 and don't want to lose too much speed in conditions in which the boat is probably at its best.

IRC says that I can get an allowance for having a roller furling headsail and a heavy weather jib only. My thinking is that the combination of a #1 with around 120-130% overlap and a max-size heavy weather jib will have a gap of about 45% of the foretriangle area, which is obviously pretty much the same as the gap you normally get when shifting from a standard #1 to a #3. There seem to be some some nice looking "foot reefing" headsails coming out of North and other companies these days; by that I mean not roller-furling ones but ones with alternative higher clew and tack positions and zippers so you can drop the whole sail down, roll the foot up and secure it with a zipper. That should help with bridging the gap.

The J/36 has an unusually stiff mast for a fractional of its era because the mast is a telegraph pole with jumpers, so we have better forestay control than comparable older swept-spreader boats.

Can anyone tell me how such a setup should perform and rate, and the pitfalls with the plan? Also, from what I can see with 36.7s and J/109s, we may get away with an assymetric only - does that sound right? We sail in an area that is often windy to very windy and normally on "round the bay" courses, and I prefer the easier handling of an assy.

I know there's very few J/36s in the UK, but there's a lot more happening with IRC optimising in the UK in this size range than down here in Australia, where neither of the two J/36s has raced IRC. For those who understandably are not aware, they have the same hull, deck and rudder as the J/35 but have a fractional rig and a more luxurious fit out down below.

 

[Judders]

If it's windy 'round your way, it may pay to go down to 108%

 

[flaming]

We race against a J35 quite often, and that thing is basically untouchable below 10 knots tws.

But.... Foresail area, especially overlap is expensive under IRC. For example the UK OD J109 setup has about a 130% Genoa and rates about 1.021. The same setup but with a 105% jib comes in about 1.008. That's a lot of points for a sail that only makes you faster in less than 15 knots upwind. And the received wisdom is that about 12 knots is the crossover between favouring the big Genoa and the little Jib.

The Solent is normally thought of as a "windy" venue. Though in reality we get a lot of everything. We (in an Elan 37) made the change down from a 130% to a 105% and went from being in and around the top 5 at big events to winning things, especially when it's windy! It can be extremely frustrating being out in 8 knots of breeze knowing there's a great big genoa in the shed, but overall there's no way we'd change back. You do need inhaulers though.

I would look into if your foot reefable jib would still qualify for the roller reefing credit though, I would actually expect that it wouldn't, given the intention of the rule.

A-sail vs symmetric is an everlasting debate. I would only say that if your aim is to be in the chocolates in a competitive IRC fleet in round the cans racing, then if your boat was designed for a symmetric kite, stick to that. I've never seen any conversions work on what you might call "traditional hull shapes".

 

[Judders]

As it goes, I've just arranged my double handed rating. Going from our 135% down to our #2 saves .010 points which is a very lot. If it were not for the fact that we have eight or nine Impalas to race against I don't think we'd ever buy a #1 again.

 

[flaming]

As it goes, I've just arranged my double handed rating. Going from our 135% down to our #2 saves .010 points which is a very lot. If it were not for the fact that we have eight or nine Impalas to race against I don't think we'd ever buy a #1 again.

Is your number 2 still an overlapper?

 

[Judders]

Yes, but only just. 105%

I believe that when I was working with Elan, the belief was the advantage kicked in between 108 and 113 though that is a few years ago now.

 

[flaming]

Yes, but only just. 105%

I believe that when I was working with Elan, the belief was the advantage kicked in between 108 and 113 though that is a few years ago now.

Are you able to inhaul in the light?

 

[Chris 249]

Thanks for the info, guys. It sounds as if I should go with the short overlap, as originally planned. I was a little bit concerned because in our only race so far we were only just as quick as our opposition in the conditions (upwind in 5 knots) that we should revel in. I probably haven't been allowing for lack of time on the boat and the fact that a ten year old cruising dacron 130% sail, even if of good quality and in fair condition apart from the leach, is probably not any faster than a racing 105-110% will be. I'm probably also not allowing for the fact that the two boats close to us where an IMS racer that is sort of like a Mumm 36 with small rig, and a Magic 25 sportsboat - both inherently faster boats.

I pulled out ORC certificates to confirm some numbers. As I suspected, we have less wetted surface than the comparable boats; about 23.5 square metres compared to about 24.5 for the J/109, 25-26 for First 36.7, 35 and Sydney 36 CR, and 27-28 metres for the comparable local 38 foot cruiser/racers. That means even if we go for a short overlap, our sail area/wetted surface ratio is in the middle of the bunch, plus of course we have the advantage of being more nimble and faster up the range.

I'm still unsure about the kite. Our low WSA may allow us to sail deep enough in light winds to do well under assy, but the comparatively narrow stern and possible lower stability could be issues when it picks up. The J/109s do pretty well with assys and they seem to be about 100kg heavier on average, which is interesting.

 

[michael_w]

Is a J-36 a fractional J-35?

 

[Chris 249]

The 36 has more furniture and is around 500 kg heavier according to orc figures and has a different keel. The mouldings are the same bar a slight transom mod. The 36 is a fractional.

 

[Motor_Sailor]

Yes the J36 is the fore-runner of the J35. It was one of Rod's earlier designs and was quite a expensive boat to build. The recession in the early 80s saw sales dry up, so they 'cheapened production' (tiller, not wheel, simple masthead rig, blocked off the mould to simplify the transom,etc) and the resultant J35 sold like hot cakes. It also had a more all round powerful rig and quickly became 'the' american mid thirties one-design boat.

I sailed a J35 double handed for years. The biggest problem was it needed weight on the rail. Your sail choices may not necessarily be constrained by the IRC rating, but getting one you can sail to, with the weight of crew you have available.

 

[Ceirwan]

My MGC 27 is rated with a roller furler and a No3 Genoa, which has the smallest of overlaps.

Since these boats originally came with an even smaller self tacker and the option of a No1, its not too much of a compromise sailing without the number one.
The previous owner added a new track inboard of the shrouds for sheeting the number 3 (the number 1 has to go all the way around the outside), which helps with pointing.
On the whole I'm happy with the setup, although I do have the same issue that Flaming described in that below 8-10kts of wind, we could do with more power.

The rating I get with this setup is 0.878 which compares favourably with other boats around our size and speed range (Impalas etc)

The advantage of this setup is when short handed which I often am, I can hold onto the headsail and reef the main, also a lot handier when cruising.

My intention this winter is to add a removable dyneema 'Solent Stay' that will be made fast just aft of the furling gear, and when the wind really picks up we can fly a heavy weather jib off it, or if necessary a storm jib.

 

[Chris 249]

Yes the J36 is the fore-runner of the J35. It was one of Rod's earlier designs and was quite a expensive boat to build. The recession in the early 80s saw sales dry up, so they 'cheapened production' (tiller, not wheel, simple masthead rig, blocked off the mould to simplify the transom,etc) and the resultant J35 sold like hot cakes. It also had a more all round powerful rig and quickly became 'the' american mid thirties one-design boat.

I sailed a J35 double handed for years. The biggest problem was it needed weight on the rail. Your sail choices may not necessarily be constrained by the IRC rating, but getting one you can sail to, with the weight of crew you have available.

Quite right re the J/36 and J/35 development. My feeling is that with modern sails, instead of the stretchy old dacron or early crosscut films that the J/36 had when it was new, the 36's rig can be potentially faster or could allow us to go for the more convenient smaller headsails.

The crew weight issue is part of the reason I want to avoid going for the standard 150% overlap. We could probably get 8 or 9 bodies for the rail, but keeping them all occupied and arranging them all is too much of a hassle. If we have smaller headsails we'll be OK with a smaller crew further up the wind scale when club racing.

Having said that, in the two races we've done so far we've had seven different crew (sailing four up each time) and everyone is very keen to come back so we may end up with too many! Our rival (an IMS 36'er like a short-rigged Mumm 36) was sailing about 8 up last weekend and we were quicker upwind in 10 knots of breeze or so, but a lot of that was due to operator error from them.

 

[bbg]

I raced a J-36 for several years in Vancouver and Seattle. We often sailed against other J-36s.

One of the boats was named "Seven". The owner had a tight crew of seven people aboard a smaller boat then when he bought the J-36 he named it after the number of people in his group. After racing against us (and other J-36s) for a season or so he really should have changed the name of his boat. He brought one more person on board, because when the boats were powered up he really needed that extra weight on the rail. Every other J-36 sailed, if possible, with eight people aboard.