Victoria Shadow Association Members' Forum

Marc_Langbroek

Member

From: Den Helder, Netherlands

Registered: 2019-03-04

Posts: 31

Dimensions of a Gennaker.

Dear readers,

As I am looking for some completions of the sail wardrobe I am musing about buying a Gennaker.
As there are lots of used ones for sale, it is key to know the dimensions of the sail.

Does anyone has experiences wit the gennaker, and is there information available regarding dimensions for a Frances 26, sloop rigged.

Hoping on some reply,

Marc Langbroek
Frances 26 "Grace Darling".

Marc_Langbroek

Member

From: Den Helder, Netherlands

Registered: 2019-03-04

Posts: 31

Re: Dimensions of a Gennaker.

Good evening to all,

The search for the right gennaker has ended with the purchase of a second hand, hardly used Gaastra one.
The dimensions are luff 9.00 m leech 8.00 and a foot of 5.00 meter.

When choosing not to order a new sail, but looking for a secondhand one, finding the right dimensions is important to decide what to buy. Second hand ones are usually given with dimension, specs and condition, so reconstructing them and fitting them on a scale drawing and then choosing the best fit / esthetical looks was the way I made my decision.

Is this the smartest way? Maybe not, but at least its less expensive as than buying new. When you're lucky halyards and sheets come along with  the sail. (Which wasn't the case with my purchase)

Finding the blocks, halyard and sheets is not that big a problem, although the costs are mounting quickly.

The result? See for yourself! I do hope that this year we do get a quiet day to do a little experimenting with the new cloth!!

Marc Langbroek
S/Y Grace Darling

Last edited by Marc_Langbroek (2020-10-24 20:21:52)

Jonathan_Hopper

Member

Registered: 2004-03-23

Posts: 155

Re: Dimensions of a Gennaker.

Looks fabulous.

Very interested in this.   Keep us posted.  Did you have to put a block on the mast for the halyard or was it existing?   How have you rigged the sheets?   Where did you buy the sail from?

JDH

Marc_Langbroek

Member

From: Den Helder, Netherlands

Registered: 2019-03-04

Posts: 31

Re: Dimensions of a Gennaker.

Jonathan,

The gennaker is a second hand one, and in pristine condition. I bought it via a very popular Dutch website called marktplaats (marketplace). The former owner told me he had used her two or three times. When handling the sail she crackles like a fresh bag of chips. The typical spinnaker cloth crackle.
For the halyard, I'll have to attach a new block on the masttop, in a way that the luff is in front of the jib furler. There is already a slot available by means of a D shaped attachment. I just tested it with the halyard of the storm jib, see pictures above. Also the tack has to be positioned in front of the furler drum, attached to the starboard flange of the anchor roller.  To prevent the tack line from chafing at the pulpit one can make use of a clew tack. A device that's been clamped around the furled jib above the drum and leads the luff or line first straight up before it can swing out. 
The sheets are being measured by two times ships length, and that 2 times. A whole bunch of rope attached to the clew of the gennaker by means of a soft shackle made of dyneema. The way of operating a gennaker is when half or abaft winds, up till force 4, while maneuvering best be done by gybing. (Hence the long sheets).
The 10 mm sheets are lead thru a pulpit mounted block straight back to the Andersen winch.
Packing can be done by means of a long tube kind of bag called a snuffer. I choose for the 'bag launching methode' . Therefor I've sewed two plastic snap hooks on the topside of the bag, so I can clip it on the guard rail, as well as for hoisting as for retrieving it back.

Reading it all back it sounds confident. Well, we all know that the proof of the pudding...

I'll keep you posted after some serious sailing with the new configuration.

Marc.

Last edited by Marc_Langbroek (2020-10-25 19:38:08)

Marc_Langbroek

Member

From: Den Helder, Netherlands

Registered: 2019-03-04

Posts: 31

Re: Dimensions of a Gennaker.

Good evening all,

As we are nearing another lockdown due to the covid misery I did some studying on gennaker peculiarities.
One of the things I noticed when hoisted was that the clew line attached to the bow veered out that much that it started to chafe the pulpit. The standard solution is mounting a clew tack. A rather costly (and simple) device, so I tried making one myself. For this I found a suitable piece of PVC sewer pipe diameter of 75 mm by 3,2 thick. A piece of 24 cm was sawed while over the whole length I removed a strip of 1 cm wide. All sides were smoothed by means of a file and some sandpapering. The top and bottom ends of the gap where rounded and all made smooth.
Now I took a electric hot air paint stripper, and started to heat one side of the gap, whole length, making it that hot that the material became soft and bendable. I bended it over a metal rod to give it a bit of a decent model. It cools very quickly and then stiffens in the final model. After doing both sides, the tack already started to look like a tack. Now again on both sides of the gap, in the middle a length of about 7 cm I gave another hot bending. These are the spots where I drilled with a 5 mm drill a series of holes, which had to become the slotted holes for the lashing band. After the drilling done, the ragged ends were being knifed away with a Stanley knife. After that with a small file the slotted hole got its final shape. Finally the top and bottom side of the tack had to be hot bended to give it a smooth ride along the furled jib. A temporary lashing was found in the shed, and the unit is now ready for some serious sea trials. Hopefully it works, while at least it is fun to make something with material that is easy to become.

Hereby some pictures of the process.

Marc Langbroek
S/Y Grace Darling

Last edited by Marc_Langbroek (2020-10-31 23:46:11)

Kevin_Misselbrook

Resigned

Registered: 2017-05-26

Posts: 42

Re: Dimensions of a Gennaker.

Hi Marc,
That looks like a substantial and creative bit of engineering.
As an alternative there is a lighter build alternative using an old fender on You Tube at https://www.youtube.com/watch?v=vu0uXjSaZR4

Marc_Langbroek

Member

From: Den Helder, Netherlands

Registered: 2019-03-04

Posts: 31

Re: Dimensions of a Gennaker.

Kevin,

I had a look at the cactus sailing video and still decided to use the more solid PVC material. It glides smoothly along the folded jib and that's in my opinion important for the long stretch. Also what I see is that letting it up en down has to be done from distance, so when it sticks one has to go forward. The fender plastic gives IMHO more friction. The gennaker is constantly in motion, so any friction has to be avoided. Note that the stitching of the lashing is being done by hand!

Marc_Langbroek

Member

From: Den Helder, Netherlands

Registered: 2019-03-04

Posts: 31

Re: Dimensions of a Gennaker.

The finishing touch...

The last point of interest when installing the gennaker hoist equipment is that the clew line leading to the clew tack had to be positioned in front of the drum of the jib furler. All to prevent the line from chafing thru.

The solution I found was in making a little bowsprit to make a fixingpoint for the block leading the clewline. As I wanted it to be temporarily, I decided to make a construction that could be held in place by the anchor pin that's been placed thru the bow fitting. As there is another set of holes for a second more aft position, a second pin was made from a stainless steel rod, massive 10 mm diameter in which a tumbler lock was fabricated. Welding the ring on the rod was done by a local blacksmith. With this, a solid fixed bowsprit was possible, easy to dismantle, but firm enough (I guess) to fits its purpose.

The bowsprit itself is made of solid 30 X 3 mm stainless steel flat. Essential is the width of the 2 10mm holes for the anchor pins. Take your time to make a good measurement, or if that's not possible, drill one hole, place the bowsprit and draw the contour of the second hole.
For drilling in s.s. use a cobalt drill and cutting fluid together with low revs to get things done.

Just another small improvement to make life on board easy !! All been done in the shed with simple tools and just a little material.

I'd just tested it this evening on board, and luckily it fitted smooth, first time. I'm looking forward to the functional testing one of these days.

Enjoy the pictures.

When interested in dimensions, just let me know.

Marc Langbroek
S/Y Grace Darling.

Last edited by Marc_Langbroek (2020-11-04 22:22:41)

Charles_Grossie

Committee Member

Registered: 2017-08-10

Posts: 154

Re: Dimensions of a Gennaker.

Nice work Marc!

---

Victoria 34 Cutter - 'Anitra'

Marc_Langbroek

Member

From: Den Helder, Netherlands

Registered: 2019-03-04

Posts: 31

Re: Dimensions of a Gennaker.

To all DIY fans,

A little addition to the making of the "bowsprit" ; When drilling in Stainless Steel, and you are not in the possession of cutting or drilling fluid, just take a fresh garlic clove, use it richly on the drill, low revvs, and the result will amaze you!!

Succes!!