Choice of Material for Snubbers

[Kettlewell]

On my mono I have tried leading my snubber from a port or starboard bow cleat, but the best route is over the bow roller, right next to the chain. The boat sails less with the lead off the bow roller. At first I was worried about chafe at that point, but it isn't significant in normal conditions. I also have the bow eye down near the waterline from which I can lead a cow-hitched on snubber with zero chafe--I mainly use that lower position for the snubber in storm conditions and/or when I need to minimize the chain out--lower angle on the chain means less length needed.

[JonJo]

Cats, monos and bridles.

Wind is not stable, it veers from side to side. If the wind is particularly unstable it can veer 45 degrees either side of the average. In small anchorages sheltered by largish hills the wind might not veer but bullets down valleys and between gaps in trees (usually in what appears to a random manner). Bullets can be opposing 180 degrees apart.

If the wind is varying in direction any yacht at anchor is going to receive that gust at an angle to the sides of the vessel (assuming it was pointed into the wind prior) so when the gust hits, on the side of the vessel it will swing on a pivot point, the bow roller, and as it swings the load will be on one leg of the bridle.

The only way the bridle legs can have the same tension is if the whole assembly chain and yacht move as if rigid and that does not happen, the chain follows the yacht, restraining it from one side.

Possibly large yachts, which might be ketches, are less prone to this yawing simply because they are heavier and yaw more ponderously and maybe not completing the yaw by the time they are hit by the next gust from the opposite direction.

If you do not believe wind is unstable, look at a wind farm - all the units point in different directions, all face the wind but the gusts are sufficiently varied that units at one side can be at almost 45 degrees to units on another. And wind farms are built usually in areas where wind direction is more stable (lots of work done on wind shear for windfarm research.

If you read the article in PS on rode loads we actually measure the angle the chain veered and the angle the yacht veered. The cat veered more. The angles are specific for a specific location and the type of wind - some winds are more stable. But I have never anchored anywhere where the wind has not varied from the average wind direction.

Wind is more stable at sea - but even then if you hand steer you are constantly tweaking the helm to keep the tell tails flying.

All yachts suffer, some suffer less than others.

Jonathan

[Kettlewell]

Sure wind is unstable, but how unstable varies a lot in different places. Down in the Caribbean it can blow from the same direction for weeks at a time, with very little local variation if you don't have much in the way of high ground between you and where the wind is coming from. When I was in the Virgin Islands once they forgot to change the weather recording being broadcast on local radio for a few days, and nobody noticed apparently because they just kept playing it over and over, but it didn't matter because the weather didn't change either. I found on my cat that with the bridle rigged she stayed pointed into the wind amazingly well, even when fairly shifty. In general, I would say cats on bridles are amongst the best at staying pointed into the wind, while light monos with fractional rigs, the mast way forward, and a roller jib right up front are amongst the worst.

[colemj]

Yes, wind veers but your description of the magnitude and frequency does not match most of our experiences.

When the wind does veer significantly, our boat mostly just moves around to the new angle with very little tension on the bridle until the boat fetches up on the chain at the new angle. At this point, both legs of the bridle have mostly equal tension on them.

For smaller wind shifts when the boat is already lying back on its bridle, the pivot point is the attachment point of the bridle to the chain - we pivot around a point 25' in front of us.

Sorry, but in no time have I seen our boat significantly pulling on one leg, then another, etc while anchored. The stronger the winds (even shifty ones), the more pronounced the sharing of the load on our bridle legs and the steadier our boat is.

Mark

[Hydra]

Yesterday was the first time I saw such severe hockling on 3-strand rope. Octoplait is supposed to be immune to hockling.

Alain

[Kettlewell]

I have seen hockling like that before, but it is usually in older line of unknown heritage that has been overstressed. Good idea to retire that bit of rope.

[JonJo]

Originally Posted by colemj

Yes, wind veers but your description of the magnitude and frequency does not match most of our experiences.

When the wind does veer significantly, our boat mostly just moves around to the new angle with very little tension on the bridle until the boat fetches up on the chain at the new angle. At this point, both legs of the bridle have mostly equal tension on them.

For smaller wind shifts when the boat is already lying back on its bridle, the pivot point is the attachment point of the bridle to the chain - we pivot around a point 25' in front of us.

Sorry, but in no time have I seen our boat significantly pulling on one leg, then another, etc while anchored. The stronger the winds (even shifty ones), the more pronounced the sharing of the load on our bridle legs and the steadier our boat is.

Mark

A 25' long rope bridle would be eaten overnight, in light winds, in sand anchorage with lumps of coral where depths are say 10'. I am sure your experiences fully valid - it could not be risked in coral or anchorages with loose rocks on the seabed. Equally we have anchorages we use to shelter storm force winds in Bass Strait where gusts come at 180 degrees to each other. We prefer to keep our bridle end to just kiss the sea, with the chain taking any abrasion. Our compromise might lead to our finding the bridle does not work as well as yours. its horses for courses I suppose.

Jonathan

[colemj]

Originally Posted by JonJo

A 25' long rope bridle would be eaten overnight, in light winds, in sand anchorage with lumps of coral where depths are say 10'. I am sure your experiences fully valid - it could not be risked in coral or anchorages with loose rocks on the seabed. Equally we have anchorages we use to shelter storm force winds in Bass Strait where gusts come at 180 degrees to each other. We prefer to keep our bridle end to just kiss the sea, with the chain taking any abrasion. Our compromise might lead to our finding the bridle does not work as well as yours. its horses for courses I suppose.

Jonathan

Funny, we anchor almost 24/7 in 10' sand with lumps of coral and even scattered coral heads. Been doing so for 5 years and our bridle is just fine. It only lies on the bottom when the wind is dead calm, where it doesn't abrade at all. When the wind picks up or the boat veers, it is pulled off the bottom. I don't see how this would be any different for rocks (I think rocks may be more gentle than coral), but we don't have many rocky bottoms in the Caribbean.

A bridle end just kissing the sea for our boat would be ~4' in calm wind and no more than 8-9' in a blow. WAY too short - little shock absorption and would cause us to sail around quite a bit.

Yes, horses for courses, but a longer bridle makes a huge difference on a catamaran in regards to sailing around the anchor and smoothing out the shock loads. For example, we just left an anchorage with a catamaran using ~10 bridle. They were sailing almost 90* tacks around their anchor the entire time while we sat rock-steady.

Mark