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Sprint 750 Snuffer Report


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#1 Strategery

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Posted 11 March 2010 - 03:12 AM

All,

In response to the emails I'm getting about the snuffer we built for the 750, I thought I'd post a
review here for you all to consider.

The Idea:
Snuffers have been used effectively on beach cats for probably the past decade
or so. First endpole, then midpole with socks that went under the tramp.
Snuffers allow fast, safe dousing of a spinnaker in a variety of conditions,
with limited crew.

After sailing the Weta with roller furling, the Nacra F17 with a snuffer, and
then seeing and talking with Phil Styne about his midpole snuffer on his Sprint,
I knew that I wanted to figure out a system for the boat. I was initially
expecting to duplicate Phil's design, but didn't want to spend too much money on
the package. I also had concerns about the exposure of the snuffer to the waves
- given what I had read about the boat's tenderness in heavy air, I wasn't
happy about that big scoop out front of the boat. Finally, I was concerned about
windage upwind - the snuffer on Phil's boat seemed to be functional, but would
have some significant square footage exposed to the wind creating both lift and
drag.

The Design
So, with Brian Harrison of Emerald Sails (now Hyde Sails), we started to
experiment with different designs. Initally we got the snuffer system off a
Nacra 20, which we rigged in a number of different positions on the bow -
midpole, endpole, and bow. While we were convinced that we could figure it out,
we just didn't like any of the mounting points. After a couple of weeks of
testing different solutions, I suggested we try modifying a bag to act as a
snuffer. It seemed like a crazy idea until we really got into it. We had more
working area than a cat - a center hull to work with, and a clean path for
retrieval lines. The design we came up with as a prototype has now undergone 5
iterations, 3 torn chutes and several modifications to materials and mouth
design. So far It has been used successfully - error free - in Key West and St.
Pete NOODs in multi-leg races in a variety of conditions.

There are a few benefits of this design that have paid off for us:

1) The boat can be safely raced with 2 people (so far in up to 20 knots)
2) Takedowns are faster - 4 to 5 seconds from chute to upwind
3) Tactical options increase - you are able to douse without driving down
4) No windage - the bag follows the contour of the coachtop
5) No drag in the water from a midpole system when in heavy air - less chance
of pitchpole.
6) All douses are fast and work - windward, leeward, jibe drops all go right in
the bag. We were worried about windward, but that turned out to be the
easiest/preferred way to drop.

Many of you have asked for design specs on the snuffer. Sorry to let you down,
but I agreed at the start of the design to work with Brian on developing
something that he could sell, and frankly I don't think I could even begin to
explain the location of the mounting points, the retrieval angles we calculated
or the math that goes into the placement of the buttons on the spinnaker for
retrieval.

His first production unit is going to be on Don Wigston's boat at the Nationals,
and I'll be really interested to see what his reaction to the design is. My
guess is that this will become a staple on competitive boats for racing, and for
cruisers who want to be able to give the tiller to a novice and douse the chute
safely while double-handing. I've used it singlehanded as well, although I
wouldn't want to do it in heavy air.

So...the downside? Well - I expect I'll wear out the chute faster than if there
was no retrieval line. I also had to learn the technique to douse - pretty
simple and consistent no matter what you are trying for a douse. Until you learn
it, you run the risk of shrimping, so make sure you talk with me or Bri before
you use it. And the last point is running the retrieval line correctly is a bit
of a challenge, but easy once you get used to it.

Stay tuned to Don's review. Hopefully he likes it as much as we do. I for one
won't be sailing on a Corsair (whether a Sprint, or a 31) without one again.

Looking forward to seeing you all in a month and a week at the Nationals. Who is
on the fence?

C.

#2 bhyde

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Posted 11 March 2010 - 11:28 PM

How 'bout some pix?

Do sprint OD rules allow a snuffer?

#3 Tom Ray

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Posted 13 March 2010 - 01:06 PM

How 'bout some pix?



and video

#4 glowmaster

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Posted 13 March 2010 - 09:18 PM

I spoke to Brian, and the cost for the bag, hardware and the spin belly button is $700 or $750. I did have a little sticker shock, but still think it is a superb idea.


ed

#5 bhyde

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Posted 15 March 2010 - 08:57 PM

Kind of curious. Is this a single line halyard/retriever/tack line system (ala I14/49er/29er/Nacras) or is each line separate? How many buttons are on the kite?

#6 SlackWater_SF

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Posted 16 March 2010 - 02:45 AM

1. How 'bout some pix?

2. Do sprint OD rules allow a snuffer?



1. Yes, Sprint.750 pictures, 2009 Nationals, Pensacola Yacht Club:
a. Timing a drop sequence w/two (2) aboard, ~30 seconds link
b. Larger pic (link.larger pic)

2. Yes, it is allowed to my limited understanding.


Fuzzy memory w/o an email look.up, the above unit was made by Lars Guck.
The gentleman who won the Sprint.750 class last year did not use a snuffer.

#7 bhyde

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Posted 16 March 2010 - 03:25 PM

As usual Slacky, nice photo work.

I saw those pictures and thought the setup didn't quite match the description above by Strategery. I wasn't sure if this was the rig they were proposing to sell or a prototype.

A couple of things that caught my eye was the shape/position/material of the bag and the retriever line coming out of the back of the bag. Having had to completely rebuild my old I14's snuffer system, I see some areas that could be improved to make the system slippery as snot.

Just my opinion (worthless), but the bag needs to be under tension from the throat to the aft end. This prevents the bag from kinking and resisting the spinnaker as it gets pull aft. A typical skiff system usually has a line from the aft end of the bag tied firmly to the back of the boat in a straight line from the throat. As the spinnaker enters the throat, the front portion of the bag will try to expand and pull material from the back of the bag forward. This creates a lot of friction and can't be allowed, so tension on the bag is important.

I'm not sure what they are using for bag material, but a real Gucci setup is to use pool-filter fabric. It's actually a fine plastic mesh that is incredibly slippery. It's light and breathable and will allow any water on the kite to quickly drain away. It also is easy to sew and combine with other fabrics. Normal fabrics (i.e. kite material) like to stick together when wet. Sliding on a mesh material greatly reduces friction in the bag.

I think the throat position might be too far forward. Having a 700 sq. ft. kite heading for the middle of the pole looks like trouble. When the two or three buttons the retriever line is threaded through hit the opening of the bag, that's a big lump hanging out in the breeze. If it hangs up that could turn into a bad day. Most skiffs have the throat located just in front of the forestay or well aft of the forestay. The reason is that when the halyard is blown you want the spinnaker as close as possible to the jib to help collapse and flatten it out. Any air flow between the retriever line and forestay is generally bad. Having the retriever line ride over the forestay is actually helpful since it flattens the kite and depowers it. The throat should also be facing up as much as possible, not forward, to reduce windage.

In the pictures, it looks like the retriever line is coming out of the back of the bag and loosely running into the cockpit. I'm assuming the crew just pulls the retriever line from behind the bag while the spin halyard is blown or eased. That might work, but the retriever line could have just about any angle leaving the bag. Combined with a loose bag, that's bad and creates more friction. The retriever line should come directly from throat to the back of the bag in a straight line. The straighter the better. A turning block mounted on the aft aka will ensure the retriever line runs right down the center of the bag and allow the crew to stay in the cockpit during the douse.

Just my $0.02 worth.

#8 richardstephens

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Posted 16 March 2010 - 03:44 PM

Strategery's system is different from Phil's (shown in the pictures from last year).

There's a video of it in action here: http://www.youtube.c...h?v=bBKJoEH8sXE

Leeward mark rounding at about the 3 minutes in.




#9 bhyde

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Posted 16 March 2010 - 04:54 PM

Strategery's system is different from Phil's (shown in the pictures from last year).

There's a video of it in action here: http://www.youtube.c...h?v=bBKJoEH8sXE

Leeward mark rounding at about the 3 minutes in.

That looks like a much better layout. They were even coming into the leeward mark pretty hot and didn't have a problem. Like to see a hoist.
For $700 to $750, if it includes the blocks, line, and bag, that might be a nice product. Plenty of F-boats around here that could use it. I'm really hoping we'll see the end of those stupid cruiser type snuffers that many people use - they're hideous and slow. This kind of system is the only way to go IMO.

Nice work Straregery. I'll have to build my own version for my F24 this summer.

#10 TheFlash

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Posted 16 March 2010 - 07:25 PM

How big could you go?

My kite hoist is 40+', which split into 3 is less than 15', and the foot max is 30, cut in half again 15'. So could one person drag 1200+ sq ft of kite into a 15' launching sock? One of those crappy cruising socks works ok - granted takes a bit of time and f's up the airflow up high. A sock would be faster and cleaner, but not sure I could handle the loads.

#11 bhyde

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Posted 16 March 2010 - 08:12 PM

How big could you go?

My kite hoist is 40+', which split into 3 is less than 15', and the foot max is 30, cut in half again 15'. So could one person drag 1200+ sq ft of kite into a 15' launching sock? One of those crappy cruising socks works ok - granted takes a bit of time and f's up the airflow up high. A sock would be faster and cleaner, but not sure I could handle the loads.


I got some carbon fiber and an old toilet seat. What could possibly go wrong?

You thinking single-line or multi-line system?

#12 Strategery

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Posted 17 March 2010 - 03:16 PM

Sorry for the lag in response...

We use a 2 line system for the halyard and the retreival line. A single line system would be cleaner, but it would not allow you to ease the head of the sail for forced reaching, you'd have to move the bag a bit further forward, and we like having it come in over the ama as a control surface. I also think that the technique works better with a dual line system, since you can use a delayed release of the tack to keep the chute from getting run over in light air.

As to how big it could go...Definitely will work on a 28. Not a doubt in my mind. I think it would work on a 31 if you had the right technique, but may be a 2 man job (which would be probably 2 less than most race with now). By preloading the retreival line, you collapse and depressure the chute, so it's surprisingly manageable. The hangups are getting the ball around the forestay and into the snuffer (which is usually driven by the size of the ring). We've solved both problems.

Thanks for posting the video - that one was taken at about 12 to 14 knots boatspeed, and we passed the 28R you see rounding in front of us. We were able to stay hot and go outside him, and then clawed up to windward. In fact, I think we got a boat at every rounding where we were coming in close in any kind of breeze. In light, light air, I'm not sure there is any advantage other than crew weight and speed of douse. In very heavy air (we've used it in 25 knots), it's an identical experience. As long as you follow the technique, it slips right into the sock.

The bag design is harder than it looks, so I'd encourage you to get a bag from Brian and save the hours and wear and tear (literally) you'll put on your chute. But...if you do it yourself, please post any improvements/ideas. I have to believe that like on beach catamarans, this design will become standard equipment on tris moving forwards.

Right now we're working on next get improvements related to windage minimization (although I don't think it's anything worse than what you'd have with a normal bag, and certainly better than having an extra bag on the starboard tramp.

C.

#13 TheFlash

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Posted 17 March 2010 - 05:45 PM

Hmmm - I built one of these back in my skiffie days - and the wife has the sewing machine...

To bobs point - a giganto toilet seat and some carbon and you're in action.


Edit

I think all I need to do is put some grommets in the belly of the sail and use the cruiser sock as a template. Just put it on it's side.

It's only what, about 5 times as large? What could go wrong?

#14 bhyde

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Posted 17 March 2010 - 08:10 PM

Toilet seat might be a tad small. Let's start with a garbage can sewed to a 10 person tent.
1200sqft kite pulled around the forestay while it's blowing 20kts+ and you're below the layline? I'll call North for you.

Could always run a loose retriever line into the forward hatch and drop old school IACC style.

#15 TheFlash

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Posted 17 March 2010 - 10:01 PM

Toilet seat might be a tad small. Let's start with a garbage can sewed to a 10 person tent.
1200sqft kite pulled around the forestay while it's blowing 20kts+ and you're below the layline? I'll call North for you.

Could always run a loose retriever line into the forward hatch and drop old school IACC style.



I was thinking about that....

#16 Strategery

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Posted 22 March 2010 - 07:19 PM

The first snuffer for a Multi 23 has been sold...

For the shorthanded cruiser, this really changes things. You get the power of the big chute (not roller-furling screacher or Code 0), with the ability to use it with almost any crew. It doesn't take any longer to douse than my F17 did, so I believe I'll be able to single hand the chute in lighter air...

C>

#17 kbcH20

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Posted 23 March 2010 - 02:35 AM

The first snuffer for a Multi 23 has been sold...

For the shorthanded cruiser, this really changes things. You get the power of the big chute (not roller-furling screacher or Code 0), with the ability to use it with almost any crew. It doesn't take any longer to douse than my F17 did, so I believe I'll be able to single hand the chute in lighter air...

C>


Got one that fits an F-27?

#18 Strategery

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Posted 23 March 2010 - 12:38 PM


The first snuffer for a Multi 23 has been sold...

For the shorthanded cruiser, this really changes things. You get the power of the big chute (not roller-furling screacher or Code 0), with the ability to use it with almost any crew. It doesn't take any longer to douse than my F17 did, so I believe I'll be able to single hand the chute in lighter air...

C>


Got one that fits an F-27?


Not sure if Brian has sold one yet, but I know he has designed one. Shoot me a note and I'll get you his contact info.




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