gennoa V jib

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Ken
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gennoa V jib

Post by Ken » Nov 15th, '18, 12:13

Hi all,
I have an interesting question, when I purchased the cal 3yrs ago the seller said he always used the gennoa, that works best, I followed suit and disregarded the original jib, all was good. Since purchasing a new main with one reef point [the original having none] I have been reefing the main in gusting conditions and enjoying the benefits. This has led me to use the original jib to see how much better life can be in wild conditions, this is a great improvement in those conditions. I continued to use the jib in all conditions and found boat speed increase, in all conditions, even very light breezes, the only issue issue I have found with the jib is she will not point as high and tacks are a little slower, I thought bigger would be better but apparently not, this leads me to ask why, or am I just setting wrong your thoughts appreciated.
Ken

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Re: gennoa V jib

Post by INMA » Nov 15th, '18, 13:55

Ken, old rig design held the theory that maximum sail area was the best way to develop power hence assortments of head sails and reefing mainsails. These old designs featured rigid masts and lots of standing rigging to hold the mast and sails in position.

In the early 1980s, some very smart Australian sailors developed lightweight masts that were designed to bend which changed the shape of the mainsail flattening it so it depowered without lots of adjustment.

My yacht is an RL24 Mk4 (INMA)which was factory fitted with one of these bendy masts that changes sail shape flattening and depowering the mainsail when the wind pressure increases. The mast is held by a fractional rig without backstays and inner shrouds are lose adjusted to hold the mast from bending too far avoiding mast breakage.

INMA sails with a full battened mainsail with roach and a modest jib. With two aboard, she sails efficiently and comfortably from calm to about 20 knots with just sail trim and shroud tension changed. This is in cruising mode not stripped out for racing.

INMA sails reasonably flat and planes at around 10 knots boat speed. on a reach or run in 20 knot winds. This is all a function of the light bendy rig and a long hull with a flattish bottom.

Nolex 25s have a similar rig but their weight and hull form are less likely to plane.

INMA's rig was developed by the same sailors who developed the 18 foot skiff rigs that revolutionised dingy sailing. The rig on INMA is often identified as a skiff rig.

The aspect of the skiff rigs (both RL24 Mk4 and 18 foot dingies) is the use of a big tall mainsail and a small 3/4 fractional jib. The jib does not develop significant power. Close hauled, the jib is sheeted close to the centerline almost closing the slot between the jib and the mainsail. Its been explained to me by better sailors that the jib's airflow redirects flow over the mainsail increasing the efficiency of the mainsail which develops better performance compared with rigs with bigger headsails.

I need to note I've cruised INMA with a smaller mainsail because the sail I use has a good reef that makes cruising more relaxed. I have not used the big mainsail for a while, still the bendy rig still does most of its magic with the smaller cruising sail.

You observation that your CAL 14 works well with just the jib is consistent with the theory the jib sheeted close to the mainsail increases the power obtained from the mainsail. The flat bottom of the CAL 14 also suits the use of just the jib because it helps sail flat keeping the top of the mainsail high in better airflow.

Yo might like to play with sheeting the jib closer to the mainsail, putting some tell tails on your sails might make it easier to trim to get the most out of your rig. It sounds like you have found a sweet balance with your yacht. As is obvious with the CAL 14 bigger is not always better.
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Re: gennoa V jib

Post by Ken » Nov 15th, '18, 15:16

thanks INMA
an interesting read, good info, makes sense,
Ken

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Re: gennoa V jib

Post by pdandy » Nov 15th, '18, 16:57

Ken, a lot of people mistake heel for speed, well done for recognising the difference.

What surprises me is your observation that it's harder to tack with jib than genoa, which doesn't make sense ( to me ) . Is it possible to get a bit more information - either pictures of your boat trimmed and pointing high , or at least some indication of what vmg / tacking angles / apparent wind you're achieving for each sail?

My suspicion is either

1 you're pointing alot higher under jib, but don't have enough boat speed to make it through the tack? Try easing the jib just before the tack, pointing down a few degrees until the boat picks up enough speed to get through the tack, then laughing as other boats drop behind you.

2 the jib might be trimmed wrong? I can't tell from your avatar, but do your jib sheets go through pulleys on a track, and are you adjusting the position between sails / different points of sail etc ?

3 sail balance....perhaps the baggy saggy old genoa is so flogged out that it's centre of action is a looong way back and producing weather helm / luffing a lot earlier and not resisting the tack? Might explain why the jib is noticeably faster? Big floppy old sails are yuck.
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Re: gennoa V jib

Post by Peter Yates » Nov 15th, '18, 17:01

Ken, how do you sheet the jib and genoa? Is there just the one set of sheeting points or do you sheet the genoa further back than the jib? It is important to have the jib sheets roughly aiming at the middle of whatever headsail you have up. If you sheet them both at the same point, one of them might be operating inefficiently.

From memory I sheeted my jib on the CAL 14 inside the shrouds and the genoa outside them. That gave differing angles but they both worked well enough and I never had any trouble tacking. The new sails I had made for Gypsy were about 20% bigger than the little original factory sails which were like shower curtain material. I sold the boat without ever using them in more than about 15 knots of wind, so can't say too much, but they certainly made her sail a lot better and point quite well.

Boats vary in how they behave when the wind gets up. Some prefer getting rid of the jib and can sail well on main alone. Others do better on the jib alone. I think the CAL does better on jib alone as does my I563. My plan with the CAL was always to reduce the main with a reef first, then drop the main if still too strong.

On the Investigator I have two reefing points on the main, so more options but basically the same plan.

The CAL is a surprisingly competent little boat and mine was a delight to sail.

Good luck!
Peter Y

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Ken
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Re: gennoa V jib

Post by Ken » Nov 15th, '18, 19:59

thanks all,
a small misunderstanding, the genoa had no issues, it was great to sail with I only noticed that when I experimented with the standard jib did I notice an increase in speed which surprised me as I assumed bigger was better. The genoa trimmed outside the shrouds and in reasonable condition, the original jib inside the shrouds in fair condition. There is no tacking issues the with the jib, just in comparison with the genoa the jib is little slower to turn. However all is good. The genoa is probably better explained as being a touch more responsive. I am researching as I will be replacing head sail in the new year and now making sure I replace the right one, as for pointing higher the genoa I feel is slightly better than the jib these are just points I noticed in comparison between the two.

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Re: gennoa V jib

Post by Tezza » Nov 15th, '18, 21:04

So how much do you attribute to the new main. I would say massive based on my experience
where I bought a new main and jib recently. Bear in mind the sonata is masthead rig and the driving sail is the headsail whereas on the fractional rig the main is the driving sail.
When you say Genoa is it overlapping.
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Re: gennoa V jib

Post by Ken » Nov 16th, '18, 07:38

Hi all,
a huge difference when I replaced the main, the genoa is overlapping it is large I would say 120 off the top of my head without measuring, I am now leaning to the hull shape being the reason for the improvement in boat speed with the smaller head sail. The cal is quite flat on the bottom and I think prefers less heel, any improvement in speed is good although a little confusing, very interesting.

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Re: gennoa V jib

Post by MartinDreaming » Nov 16th, '18, 14:35

Tezza wrote:
Nov 15th, '18, 21:04
... the sonata is masthead rig and the driving sail is the headsail whereas on the fractional rig the main is the driving sail.
Thanks Tezza and everyone else contributing to this thread. My boat (Austral20) is a masthead rig, and gets most of its drive from the headsail/genoa. Normally, I put the main up first and then unfurl the headsail/genoa. Based on this, I reckon the main is worth about 0.5 to 1.5 knots. The headsail/genoa takes it up to 4.5 to 5.5 knots, or easily makes 4 knots on its own off the wind, meaning that it is worth, maybe, 4 to 5 knots. The main is, maybe, 10 years old and the headsail/genoa was new in January. Without doubt, these speeds could be improved by better trimming. I've not spent a lot of time on fractional rigs to compare, but I can see how the main makes a bigger contribution, with less weight up top.
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Re: gennoa V jib

Post by Frank Peters » Nov 16th, '18, 16:14

Hi All,
After many years of sailing different boats, I have established my priority.
I simplify my sailing wardrobe to No,2 Genoa on aluminum extrusion and furler.
I still carry jib, but only for back up, permanently in locker.
Genoa on furler allows me to set the size I need with very little effort.
In some conditions I only use Genoa and even for motor sailing I can unroll what I need. I also never reef my main.
Noelex is very good compromise boat and never need to bend the mast and it is fast enough to get me in time for Happy hour.
Regards Frank

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Re: gennoa V jib

Post by INMA » Nov 16th, '18, 16:40

Frank, you missed my point about the Nolex rig, the mast bends as wind pressure increases without you doing anything.

As wind increases your sail adjustment would be to flatten the lower mainsail with the out haul while the top of the mast bends to let the top of the mainsail flatten and fall away dumping wind. M.odern rigs like the Nolex 25 are wonderful.
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Re: gennoa V jib

Post by impulse » Nov 16th, '18, 17:25

Generally one would expect improved pointing with a jib than a genoa. In flat water there is no reason why a smaller jib wouldn't perform as well as a larger genoa. I light airs one would expect a genoa to be faster all other things equal.
Generally I would also expect a boat to tack easier with a smaller ( less overlap) headsail.
How are you determining your pointing angle with each sail and how are you measuring your boat speed ?
Cheers Robin.

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Re: gennoa V jib

Post by pdandy » Nov 16th, '18, 19:43

Frank Peters wrote:
Nov 16th, '18, 16:14
Hi All,
After many years of sailing different boats, I have established my priority.
I simplify my sailing wardrobe to No,2 Genoa on aluminum extrusion and furler.
I still carry jib, but only for back up, permanently in locker.
Genoa on furler allows me to set the size I need with very little effort.
In some conditions I only use Genoa and even for motor sailing I can unroll what I need. I also never reef my main.
Noelex is very good compromise boat and never need to bend the mast and it is fast enough to get me in time for Happy hour.
Regards Frank

For what it's worth, this is a very unusual approach to sailing a noelex. The boat was designed main dominant, fractional rig, self tacking jib. It performs extremely well in that configuration, and I trust the advice of a multiple noelex champion who explained the genoa has a very limitted wind range where it improves performance. Whilst I have a VERY nice genoa, it only comes out when racing in 3-7.5 knts, the rest of the time I find the jib / main configuration faster - INCLUDING ultralight winds like the mponr.

I'm going to be REALY embarrased if frank drifts past me under just genoa .....
noelex 25 green velvet

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Re: gennoa V jib

Post by Ken » Nov 21st, '18, 08:49

thanks for the info interesting subject too many variables, the main point I missed was the obvious, the condition of the original jib is fair at best [30yrs+] which would explain its slow response, should be a different scenario if it was new. I have found very little evidence of gennoas of the size I have on fractional rigs appear to be used more on mast head rigs, hard to get definite info on this subject due to the variables, every boat is going to react differently, so if it ain't broke don't fix it. I will continue to enjoy sailing and keep experimenting;
sheet gennoa further aft
replace jib [new]
review sail trim/balance
the good news is I have found a new turn of speed which is great, just when I thought I had hit the max for this little boat sailing has just kicked up a notch, how much more can I find ? my brothers Sunmaid 20 may not be in front as far next trip. HoHo

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Re: gennoa V jib

Post by Peter Yates » Nov 21st, '18, 09:48

Ken, the CBH for the CAL is about 0.560 and the Sunmaid about 0.615. That indicates that the Sunmaid is only about 10% quicker than the CAL, so with good sails and good skills, you could possibly keep up with a Sunmaid.

But the Sunmaid does have a longer waterline length which gives it inherently greater hull speed, so you will be up against it!

Having said that, with enough power, boats will exceed their hull speed. While it won't impress many folk with longer boats, we hit over 6 knots occasionally with our CAL and that feels a lot faster being so close to the water! Our Investigator has a CBH between the CAL and the Sunmaid and the best we have seen yet on her has been a sustained 6.6 knots and a burst at 7.2 knots.

How do you measure your speed? We have a GPS based "Speedpuck" which has AA batteries and does not need to be wired in. It is completely accurate in terms of your speed over the ground, so will only give your actual boatspeed through the water if there is no current. It is a handy device as it also has a selection giving your track as well.

We miss our little CAL but very happy with the Investigator.
Peter Y

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Re: gennoa V jib

Post by Ken » Nov 21st, '18, 13:16

thanks Peter
speed is not important I enjoy the sailing more, however makes for good fun, good conversation and a laugh with a beer at anchor. My speed is seat of the pants when solo and info from the sunmaid when in company. I know what you mean about cal14, there is something special about them, I have helmed the sunmaid and found it a great boat to sail when I returned to the cal my grin increased they are a lot of fun I think I would miss mine if I did not have it.
However I may still buy a larger boat in the near future, as family and grandkids want to come sailing on overnighters and at the moment I can only take one at a time, I think I will still keep" Lucy Anne" for myself.

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