Nacra 15 FCS for fun

So maybe this sequence of photos help, we are going down wind...the leeward hull starts to fly upward quickly. Response to this is to slowly head up into the wind and tighten the main to try and get it (lee ward hull) to go back down...at some point though the spinnaker starts to luff (collapse as you can only go up into the wind so much with the spin) and you have no more ability to get the leeward hull down and it continues to rise ... so we are on the verge of getting T-bagged..so the question is what options do you have when you get to this point moving inward is a given although difficult at this point ...is there anyway to get that leeward hull to rotate back down (move forward or backward?? Cunningham?)...or simply we let it go too far and we are screwed.

On the gybe we havnt been doing that, we have been moving in after the leeward hull is in the water so we are late...will give that a try

Downwind we do run with the mast rotator loose and all the way out, cunningham is eased...just havnt played much with trying to optimize the power as we are currently in survival mode

Cant believe you consider the F15 rudder dull I find it "twitchy" as hell compared to the H16 when in the air
It
Could post some pics of the foil repair process here or in Fix It...if you think it would be helpful

R

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martin 'hoff

Super Anarchist
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So maybe this sequence of photos help, we are going down wind...the leeward hull starts to fly upward quickly. Response to this is to slowly head up into the wind and tighten the main to try and get it (lee ward hull) to go back down...at some point though the spinnaker starts to luff (collapse as you can only go up into the wind so much with the spin) and you have no more ability to get the leeward hull down and it continues to rise ... so we are on the verge of getting T-bagged..so the question is what options do you have when you get to this point moving inward is a given although difficult at this point ...is there anyway to get that leeward hull to rotate back down (move forward or backward?? Cunningham?)...or simply we let it go too far and we are screwed.

So lee hull is lifting quickly, you're about to teabag. 3 reasons/scenarios

- Mainsail trav&sheet too open. It needs to be carried surprisingly tight. Trav centered, and main, just a bit eased from an upwind trim point. Less eased from the upwind trim than you think :)
- Kite overtrimmed, stalled (to a lesser extent, mainsail stall). Crew must have eagle eyes on kite telltales, and be trimming to keep the lee telltale happy all the time. Windward telltale is important but secondary. The power is "outside" not inside. So when falling to windward, ease (counterintuitive, I know)
- Wind has dropped, you've sailed into a big lull. Try get your bodies onboard as gracefully as possible, but also, get used to mild teabagging. If your body is going to hit the water, trim whatever line you have in hand, hard, to put positive pressure on your feet to keep you stable.

Edit: heading up and slight ease on main are also part of the solution for of of the scenarios: over-trimmed sailplan and lighter wind.
 
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Your 1st point is likely true...we probably sail with the traveler and sheet too open...will look at rectifying that

Were pretty good on the kite, only really get a stall on it when we come up too far trying to get the leeward hull to settle back down, but we definitely dont ease it when "falling to windward"..so will give that a try

When we get big gust differences there doesnt seem to be much you can do and it is easy to get caught out.

I would say overall and in general we seem to be chasing the wind a bit more than we should, particularly when we look at your videos

Did get it foiling upwind a few weeks ago, 3 on leeward side and -2 on windward side in about 10 knots of wind, found it was easier to handle and we were able to double trap once we got it foiling
 

Olsalt

New member
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On the water
You have to maintain pressure on the leeward hull! From what I can see on the pic the mainsheet is way too open. You don't have to play with the cunningham. What you can do in this situation is steer to windward to get more power. Leeward hull starting to foil is usually a result of bearing away too much. If you are in a gust, ease the mainsheet and try to accelerate. Have you tried two on the wire? On the foiler you have no safe spot. But the safest way is that the boat only foils if sailed completely flat with helm and crew on the aft position and low on the wire. That gives you heel and crew position as control options.
 
Will be back on the water today, providing the wind cooperates. Will try to put the advice provided above to use. We havnt double trapped as yet downwind (even in high winds) as we were still trying to figure out the boat handling but I agree we should probably start doing this ... and I actually find driving the boat off the trapeze is easier than sitting in particularly when soloing. Not worried about dumping thats just part of the program, although the damage to the spinnaker last time was unexpected, looks like it somehow caught one of the battens when we went over

Got the new decksweeper from North Sails yesterday, looks awesome...cant wait to try it out...came with batten tension adjusters very nice. They also did a good job repairing the 4 ft long rip in the spinnaker could barely tell where they did the repair

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martin 'hoff

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We (probably) won a long distance race on Saturday. Corrected time not confirmed yet. It's an informal race and there was some confusion over ambiguous course.

Seaweed management was a big deal in this race - stop, sail backwards... back on. We had a great start but the camera wasn't on.

In medium unsteady breeze reaches, it's hard to keep the pace with a well sailed H20. We could foil but it was very unstable, probably because of the inboard shift in CoLR - skimming/planing gave us better average speed and control.

Downwind foiling was tough due to swell and seaweed but we just outpace everyone on this fleet - this time looks like we were the only Spinnaker cat.

Whatever the final score we had an absolute ball.

 
Sounds like fun, excepting the seaweed that is ... need to come up with a seaweed cleaning device.

We raced for the first time yesterday with the F18s in short fleet races (1 upwind / 1 downwind). Windspeed was in the 8-10 knt range so we basically got our ass handed to us...wind was too low for our crew weight, find the boat needs to be able to do about 9-10 knts boat speed upwind before it starts to come into its own, and we could only manage 5 - 8 knts. Although we did satisfy ourselves that we could catch up on the downwind legs given enough wind, at times we were up to 15 knots and could close the gap reasonably quickly at those speeds. Will be more interesting in a 12-14 knts. Oddly I took a dive off the boat to check the foils and rudders for seaweed as we felt we were under performing for the wind conditions, but it was likely a combination of the low wind, wave shape (short and choppy...not great for our waterline length) and tidal current we were in....
 
Below is some preliminary video from the F15 in 20 - 25 knt winds and 3 foot and larger swells. Some big nosedives and decelerations when going with the waves, boat was almost too fast as you would get up to 19 knts boat speed and then crash through the wave in front...and the deceleration's were wicked. We were raked at 1, dont know if we raked more in those conditions whether we would have gone over the front waves if we were flying higher as you were basically skidding down the wave fronts into the troughs. Foiling across the waves in the other direction was a bit better but similar issues...we were able to foil upwind at times but it was hard to sustain with the big waves lifting the boat out of the water. Flipped twice, it went turtle once (fortunately spin wasnt up at the time) didnt know the Nacras would do that...think the wind and waves blew it over...anyway it came right up no harm no foul...thank god for helmets, can see why a kevlar wet suit would be handy.. we were getting cut through the 3mm wet suit ... probably not optimal wave conditions for foiling ... regardless fun as hell!

Downwind with waves



Downwind across waves

 
One of the guys at the club wanted to try filming the boat foiling with a drone. We had 10 - 12 knts wind and flat water which was perfect unfortunately the wind died after about 10 minutes of filming and we couldnt foil anymore. Anyway it was a good test run for the drone, to see what its capability and range were....plan is to repeat it on a 12-14 knt day and from a chase boat at the same time...should be interesting, always wonder what it looks like from an off boat perspective.

Anyway regardless of the wind conditions, the footage is still spectacular ... shout out to David Fearn (Vancouver,BC) for bringing out his drone and filming and putting this video together....the 4K version is unbelievably sharp

 
Couple more videos from a higher wind and wave day. Tried some upwind foiling, bit hard with the bigger waves...think we managed to get it semi-foiling at least ... only once on a flatter wave day did we have it foiling completely out of the water for short periods of time ... unfortunately no camera on as it occurred completely unexpectedly...Martin is it possible to get the boat out of the water and foil stably for extended periods of time upwind or mostly you are skim foiling when running the differential rake upwind? Got any footage of upwind foiling in the F15?

Upwind


Downwind on same day

 
New Decksweeper arrived from North Sails a couple of days ago, its a full size one not a reduced sail area one like the one on the FCS One. Very nice looking cant wait to try it out. This was its firts fitting on the boat needs a few modifications as Cunningham grommet was a bit too high, the sail alignment tab that goes in the mast groove was a bit too high and it was to have and additional vertical batten in the lower sail region next to the mast...will get those remedied and then give it a go...should be interesting to see how it compares to the regular mainsail. Anyone have any experience or words of wisdom with regard to sail trim on a decksweeper?
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martin 'hoff

Super Anarchist
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Couple more videos from a higher wind and wave day. Tried some upwind foiling, bit hard with the bigger waves...think we managed to get it semi-foiling at least ... only once on a flatter wave day did we have it foiling completely out of the water for short periods of time ... unfortunately no camera on as it occurred completely unexpectedly...Martin is it possible to get the boat out of the water and foil stably for extended periods of time upwind or mostly you are skim foiling when running the differential rake upwind? Got any footage of upwind foiling in the F15?

Upwind


Downwind on same day


That looks fantastic! Great posture on the wire!

Upwind foiling can be made to work but it's bad VMG for two reasons: you're footing a bit, and you need a brief bear away to take off.

The rudder rake matters - i know of N17 teams that tried more rudder rake (symmetrical) and would foil better upwind, but if you set the boat for upwind foiling it's in a bad configuration for downwind (where you need less rake on the rudders). And we now know that with rudder rake differential you foil upwind so much better. But we don't have that kit on the N15 :-(

Anyway - playing around with the stock N15FCS, to get some upwind foiling, you'll probably want a much tighter mainsheet and fly a hull solidly, conventionally. Build up speed, slight bear away with an ease on main that (A) matches the bear away and (B) releases the downforce pressure and allows the boat to pop. For style points you could put the rake on right on B.

What we do instead in our long distance races is to sail upwind conventionally, and use a little bit of rake (asymmetrical) to get the bow out of the chop. Skim/plane and every 10th wave a short flight. Pays off in spades.

Just watch out that if you want to handle a big gust with an ease or a luff that unloads the rig, you'll pop out and if the gust is strong you might feel out of control. I try to ease a little bit less than I'd naturally ease, to keep the rig loaded.

One downside of the Z boards is that the moment you actually pop out, the CoLR shirts inboard by 50cm or so, so you lose a ton of leverage. On upwind and reaching legs this makes the ride a bit wild.
 

martin 'hoff

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New Decksweeper arrived from North Sails a couple of days ago, its a full size one not a reduced sail area one like the one on the FCS One. Very nice looking cant wait to try it out. This was its firts fitting on the boat needs a few modifications as Cunningham grommet was a bit too high, the sail alignment tab that goes in the mast groove was a bit too high and it was to have and additional vertical batten in the lower sail region next to the mast...will get those remedied and then give it a go...should be interesting to see how it compares to the regular mainsail. Anyone have any experience or words of wisdom with regard to sail trim on a decksweeper?
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That looks wild! It's that a standard SKU?

The deck sweeper I'm aware of matches size with the regular main, "just moves the cloth lower" for lower CoE for the solo configuration.

This sounds like it packs more power. What's the size?
 
Hey Martin

Agreed, no advantage to upwind foiling if your racing, we also go with the skim foiling upwind for lack of a better term....was just one of those things we thought we ought to try to see if we can do and what kind of performance numbers we would get out of it...Atlas will give us a good read on the VMG difference .... Will give your advice a try

FCS One decksweeper is listed as 145 sq ft and the FCS regular main is listed as 148 sq ft (at least according to the Nacra site and when I scaled it off it appeared slightly smaller), dont know what the exact number is on this one yet but I did lay it over the existing regular main and this one completely covers it and is of course longer so its probably running somewhere around 150 - 151 sq ft if the number for the regular sail is correct. North apparently modelled it after their F18 decksweeper, first one I think they have done for the F15. Regardless cant wait to try it out, probably another week or so before its ready
 

martin 'hoff

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Wow I would have sworn I had checked the specs and found them to have same size. Ok, it is slightly smaller.

I'm impressed with that bigger main!
 
Hi Ken
Ahh...the Rum Runner Regatta....Will keep an eye posted, we should be down there both days if there is a decent amount of wind ... boat sits amongst the row with the F18s and the A Class Cat, blue Nacra cover on it ... pretty easy to find ... look me up for sure if you have time.
Roger
 

Mako73

New member
I know it's not a Nacra 15 FCS but we went for the Foiling Viper Convertible for our 2 x sons after campaigning a Nacra 15 and wanting to go into the F16 fleet. The Viper was the obvious choice as we have best of both worlds. The Foiling Viper foils well to windward and with the rudder rake and diff makes it all a lot safer and faster as you can adjust as needed and not just live with it until you crash. Here is a link to a short video. Also they have a Facebook page "Vanquish Sailing" which will keep getting updated with photos, info and videos.



Mark

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