Thread: Is that a 12' GIS I see hull down on your horizon

Well ...

Rick has the hull ready for the deck.

I ordered the sail and sailtrack a week or so ago with a estimated delivery time of 3 to 4 weeks.

Fastenings list is being chased up by Rick - some odd bits of tubing for mast rotation spanner (control arm fixed to mast) and some bits of rod.

I've put in an order for all the fittings with Duckworks who now also are starting to carry the Australian Ronstan range of fittings - which has my very favourite small plain sheave blocks and other items.

To get an idea of the rig controls I put this pic together of an NS14 with labels.

NS14 rigging details.jpg

It looks like a compatible product available in Oz is Liros D Pro, which is SK75 heat treated AND pre-stretched. 4mm has a breaking strength of 1250kg, which is a lower than Dux, but more importantly has 1/3 less stretch than Dux. The problem I'm having getting my head around is that even this low stretch stuff can stretch 1%. I presume this 1% stretch is at the working load of 625kg? Let's divide this working load by 4, which is probably a reasonable assumption, so that at 156kg, a reasonable estimate of the load on the stay, the stretch is approximately .25%, assuming it's linear. That means a 4m stay will still stretch 1cm. If 3 stays stretch 1cm, that's 3cm of slop introduced into the rig, which I don't think I'd be happy with.

Originally Posted by Boatmik

Well ...

Rick has the hull ready for the deck.

I ordered the sail and sailtrack a week or so ago with a estimated delivery time of 3 to 4 weeks.

Fastenings list is being chased up by Rick - some odd bits of tubing for mast rotation spanner (control arm fixed to mast) and some bits of rod.

I've put in an order for all the fittings with Duckworks who now also are starting to carry the Australian Ronstan range of fittings - which has my very favourite small plain sheave blocks and other items.

To get an idea of the rig controls I put this pic together of an NS14 with labels.

What is that on the front of the mast MIK? Looks like it could be some sort of mast bend limiter, probably the adjustment end of a jumper stay?

Have you seen the latest pic of my Moth controls (from my blog)? The primary line is a single spliced 3mm SK75 line. Note the 6mm thimbles on the vang and outhaul. Mainsheet is 8mm so it's a bit thick and slow through the blocks. Will either use the 5.6mm Rooster or 7mm Bzzz line from NE ropes.

You will need to click in the image to expand it.
IMG_1004 (1024x768).jpg

Originally Posted by BobWes

Sort of but not really... How do you know when enough is enough? What load? How do you know when it stops stretching at that (whatever) load?

Good question...

First I "calibrated" the comealong I had so I had an idea of the ratio of pull on the handle to the pull on the hook. I used a spring scale on the handle and weights on the hook. Once I had the ratio I decided to add and extension to the handle so I could use the spring scale and be withing the range of the scale.

After stringing every thing together, [pole]<-->[comealong]<-->[pre spliced shrouds]<--[pole], I pulled on the extended handle with the scale until the scale read the 50 pounds that I figured to equal a hook pull of 2500 pounds.

This was for 1/4" AmSteelBluePlus rated 9200 lbs -- so I was tensioning at about 25% of the limit -- which was also twice the righting moment for the boat (which is same as twice what the max load would ever be on the shrouds) so I felt I had plenty of safety margin there.

I just measured from the telephone pole past the comealong to the thimble on the shrouds as my reference for whether the length was changing as I applied tension. I did let things set for a while between reloading the line back up to the 3000 target as the I went along. Eventually after maybe 8 or 10 times of bringing the load back up it stopped stretching (as close as I could measure anyway).

It's simpler when you're doing it than reading about it.

Originally Posted by woodeneye

What is that on the front of the mast MIK? Looks like it could be some sort of mast bend limiter, probably the adjustment end of a jumper stay?

@woodeneye, I think that is the bottom of the diamond stays. The mast is rotated towards the camera so what appears to be the front is actually the side.

Tim

Originally Posted by tpb03

@woodeneye, I think that is the bottom of the diamond stays. The mast is rotated towards the camera so what appears to be the front is actually the side.

Tim

Yes Tim, you're right, my geriatric brain was confused by the weird fisheye perspective. Actually, it's a great shot as you don't often see one pic that shows the whole cockpit and control line arrangement and the crew hiking as well. Skipper and crew in alignment to reduce windage too .

Sheeting from the boom is a good idea as it reduces clutter in the cockpit so you can cross the boat without obstruction and it reduces the amount of sheeting to handle. It also makes cleating the mainsheet difficult which is a very good thing! The only downside is one less purchase, but it's a smallish sail so should be easily handled by most people. If not, another purchase can be added by starting the sheet at the block that's attached to the bridle.

The blocks on the vang look like 30mm so are probably a bit overkill. You could happily go down a size to the 20 series. Same with the vang lines. These look like 6mm on both primary and control line. 3mm would be fine for both and then size the cleats accordingly. If you wear gloves, and you should, it makes handling the thinner lines easier too.

The mainsheet is also a bit thick. Nowadays, the trend is getting down to 6mm for lower friction and faster running through the blocks. Lighter sheets also help keep them out of the water when going downwind in light air. A good compromise that still works well in the smaller 40 series blocks is 7mm, but it's hard to find as it's a specialty size. If you are interested in a certain 7mm brand that is just simply awesome, lightweight, comfortable in the hand, doesn't absorb water, doesn't tangle, and will work for all Storer boats, check out Bzzz Line from New England ropes. It's also cheap as chips.

Originally Posted by woodeneye

It looks like a compatible product available in Oz is Liros D Pro, which is SK75 heat treated AND pre-stretched. 4mm has a breaking strength of 1250kg, which is a lower than Dux, but more importantly has 1/3 less stretch than Dux. The problem I'm having getting my head around is that even this low stretch stuff can stretch 1%. I presume this 1% stretch is at the working load of 625kg? Let's divide this working load by 4, which is probably a reasonable assumption, so that at 156kg, a reasonable estimate of the load on the stay, the stretch is approximately .25%, assuming it's linear. That means a 4m stay will still stretch 1cm. If 3 stays stretch 1cm, that's 3cm of slop introduced into the rig, which I don't think I'd be happy with.

We do tend to think of the wire as not really stretchy.

But the reality is that the lee shroud does come slack because of a combination of bits of the boat moving elastically. This very much includes the wire.

MIK

Originally Posted by woodeneye

Sheeting from the boom is a good idea as it reduces clutter in the cockpit so you can cross the boat without obstruction and it reduces the amount of sheeting to handle. It also makes cleating the mainsheet difficult which is a very good thing! The only downside is one less purchase, but it's a smallish sail so should be easily handled by most people. If not, another purchase can be added by starting the sheet at the block that's attached to the bridle.

In the end the NS14s moved to more of a vang sheeting setup - in most photos I found there is no traveller (much like the Goat traveller but with adjustment to each side). Just a bridle centralised like a sprit rig OzRacer. The Goat needs a rope traveller because it helps the leach tension upwind. But this is not a consideration in the NS14s any more (by photo evidence only)

The blocks on the vang look like 30mm so are probably a bit overkill. You could happily go down a size to the 20 series. Same with the vang lines. These look like 6mm on both primary and control line. 3mm would be fine for both and then size the cleats accordingly. If you wear gloves, and you should, it makes handling the thinner lines easier too.

With the vang, the problem used to be that the top block with a 16 to one vang like this would have such a high load the balls would deform because of the constant high load so the top block would be a plain bearing with a metal sheave - not over the working load but the balls would deform in the same way that the Dyneema does - responds to a constant load over time.

MIK

Originally Posted by Boatmik

We do tend to think of the wire as not really stretchy.

But the reality is that the lee shroud does come slack because of a combination of bits of the boat moving elastically. This very much includes the wire.

MIK

That's very true MIK, but my experience is that mast bend upwind is mostly to blame for the leeward shroud becoming loose because this is when the leach is under the most tension and the mainsheet is pushing the boom. Mast bend = lowering of the hounds. But yes, of course wire does stretch.

It is something that is worrying me a bit with the Moth as the mast pin and step seat is only 8mm. With pounding into waves upwind it could jump out when the leeward stay goes slack. I think I'd be happier if the pin was longer.. Then I think, naaa, it would have happened before now if it was a problem. But it's definitely a niggle in my mind.

Originally Posted by Boatmik

In the end the NS14s moved to more of a vang sheeting setup - in most photos I found there is no traveller (much like the Goat traveller but with adjustment to each side). Just a bridle centralised like a sprit rig OzRacer. The Goat needs a rope traveller because it helps the leach tension upwind. But this is not a consideration in the NS14s any more (by photo evidence only)



With the vang, the problem used to be that the top block with a 16 to one vang like this would have such a high load the balls would deform because of the constant high load so the top block would be a plain bearing with a metal sheave - not over the working load but the balls would deform in the same way that the Dyneema does - responds to a constant load over time.

MIK

The MG14s were the same MIK, just a bridle with no traveller as is the case with the modern skiffs too, like 49er, 29er etc. The 470s and 505s and lots of other classes that once used a traveller have also converted. The Moths are also using a bridle, but it's central and in front of the helm. My scow has a wire traveller, but the travel has been restricted to its central position with a tied off control line. Because of the relatively high boom, it would be quite possible to convert it to a bridle, but will wait for a first sail before going this route. I was thinking of a rear bridle, but read on a forum somewhere that it's been tried and didn't work, hence the central version. The rear versions on most boats do need a bit of a mainsheet flick when gybing to prevent the sheet wrapping around the transom corners.

As for the vang blocks, hehe, I was going to aah mention aah, that balls of steel are required. But I won't.

Originally Posted by woodeneye

That's very true MIK, but my experience is that mast bend upwind is mostly to blame for the leeward shroud becoming loose because this is when the leach is under the most tension and the mainsheet is pushing the boom. Mast bend = lowering of the hounds. But yes, of course wire does stretch.

It is something that is worrying me a bit with the Moth as the mast pin and step seat is only 8mm. With pounding into waves upwind it could jump out when the leeward stay goes slack. I think I'd be happier if the pin was longer.. Then I think, naaa, it would have happened before now if it was a problem. But it's definitely a niggle in my mind.

I think the Taser uses quite a short pin.

On NS14s there used to just be a plastic pulley forced onto a 6mm diameter pin that was dropped into a hole on the deck. Downside was that you could push the pin through unless there was a washer welded onto it. Do you think that your pin might have just pushed through a bit? Or maybe it is all mothish weight saving!?

MIK

Originally Posted by Boatmik

I think the Taser uses quite a short pin.

On NS14s there used to just be a plastic pulley forced onto a 6mm diameter pin that was dropped into a hole on the deck. Downside was that you could push the pin through unless there was a washer welded onto it. Do you think that your pin might have just pushed through a bit? Or maybe it is all mothish weight saving!?

MIK

This is the the mast step billet and pin fitting on the base of the mast. I don't think either are available any more so if I changed the arrangement I'd have to go with something else. (The red thing is a 1mm thick piece of HDPE from a food preparation mat. Makes a good lubricant to help reduce friction when the mast rotates)The pulley/pin idea sounds OK.

I reckon those old tuffnol sheaves would be the go to form a mast step and use a ss pin epoxied into it (or into the mast). If it was backed with a bit of 3mm ally plate, it would stop the pin going through the deck. You can still buy them you know!

haha .. that brings back memories. The deck fitting is from Sapphire and was anodised blue.

I've seen them in chandleries occasionally. They made spreader fittings and hifield levers as well (anyone remember those?) drum winches (a less remote memory but still a long time back) also some wormscrew cranks for tensioning up bits and pieces of standing rigging.

MIK

Bwaaaaa, my Moth has an ornery old off-the-shelf mast step . I had visions of the builder casting the fitting in a home made mold. I'm shattered....