Mainsheet traveller system question

[leachs4]

Firstly let me say I am new to the world of yachting so this may be a daft question (an my terminology may not be 100%) but this is starting to drive me mad so have come here for advice.

I have just replaced all the rope on my project boat (a seawych 19) and understand it parts except from the mainsheet traveller system.

The boat was converted before I purchased it to have and inboard well, so someone has cut out a well in the stern.
I think the seawych would have been sold with a horse but there appears to be no ‘horse’ on the boat however there is some 10mm rope that is attached on both sides of the stern which forms an upside down V when lifted (I think may be some kind of bridle??).

At the end of the boom there is a metal bar with a hole at each end and attached to the boom with a bolt in the centre and will rotate 360 degrees

I assume these two parts can be connected to make a traveller system but I am trying to understand what I need to make this work. But may require hardware ?

Any advice will be greatly received.

Steve

 

[lw395]

You can either rig the mainsheet so it slides across the rope bridle, in which case the bridle needs to be fairly tight.
Or you can simple rig the sheet from one deck eye, up to a block on the end of the boom and down to a pulley block on the other deck eye and off to your hand.
The idea of letting the sheet slide across on the horse is that it pulls the end of the boom down. Without the horse, you will rely on the kicking strap AKA vang more. That's Ok if the boom is reasonably stiff. In fact these days it's often preferred.

 

[RichardS]

You can either rig the mainsheet so it slides across the rope bridle, in which case the bridle needs to be fairly tight.
Or you can simple rig the sheet from one deck eye, up to a block on the end of the boom and down to a pulley block on the other deck eye and off to your hand.
The idea of letting the sheet slide across on the horse is that it pulls the end of the boom down. Without the horse, you will rely on the kicking strap AKA vang more. That's Ok if the boom is reasonably stiff. In fact these days it's often preferred.

I have a similar arrangement on my sailing dinghy but you do need some kind of fixing or cleat to secure the boom over to one side of the centre line or the other. If you just use an upside down V of line the boom will always move back to the centre no matter how tight the V.

My dinghy has a jamming cleat at either side of the stern and two separate loops of line which go from the side to the ring on the boom end and back to the jamming cleat so you can hold the boom end exactly where you want by "balancing" the two loops of line. You can use pulleys and blocks as required to reduce the friction.

Richard

 

[NickRobinson]

........At the end of the boom there is a metal bar with a hole at each end and attached to the boom with a bolt in the centre and will rotate 360 degrees .........

Any advice will be greatly received.

Steve

Great starter boats! Sounds like your Wych has the main boom roller reefing, same as my old Seawych, Keyn Vor, One hole in that plate takes the main sheet and the other the topping lift.

There may be a square socket on the goose neck that takes a little crank handle to rotate the boom.

Got a pic of the engine well?

 

[lw395]

I have a similar arrangement on my sailing dinghy but you do need some kind of fixing or cleat to secure the boom over to one side of the centre line or the other. If you just use an upside down V of line the boom will always move back to the centre no matter how tight the V.

My dinghy has a jamming cleat at either side of the stern and two separate loops of line which go from the side to the ring on the boom end and back to the jamming cleat so you can hold the boom end exactly where you want by "balancing" the two loops of line. You can use pulleys and blocks as required to reduce the friction.

Richard

There are 200,000 laser dinghies and I don't know how many Toppers, Picos etc etc that would suggest no controls on the rope horse are necessary. Most have the horse quite tight, the lasers go for 'as tight as possible, then a bit more'.

 

[RichardS]

There are 200,000 laser dinghies and I don't know how many Toppers, Picos etc etc that would suggest no controls on the rope horse are necessary. Most have the horse quite tight, the lasers go for 'as tight as possible, then a bit more'.

All I said was that an inverted V of line will not suffice ...... and not according to this Laser video either https://www.youtube.com/watch?v=wSnlcq_hSnA

Richard

 

[VicS]

Firstly let me say I am new to the world of yachting so this may be a daft question (an my terminology may not be 100%) but this is starting to drive me mad so have come here for advice.

I have just replaced all the rope on my project boat (a seawych 19) and understand it parts except from the mainsheet traveller system.

The boat was converted before I purchased it to have and inboard well, so someone has cut out a well in the stern.
I think the seawych would have been sold with a horse but there appears to be no ‘horse’ on the boat however there is some 10mm rope that is attached on both sides of the stern which forms an upside down V when lifted (I think may be some kind of bridle??).

At the end of the boom there is a metal bar with a hole at each end and attached to the boom with a bolt in the centre and will rotate 360 degrees

I assume these two parts can be connected to make a traveller system but I am trying to understand what I need to make this work. But may require hardware ?

Any advice will be greatly received.

Steve

To answer your questions and ignoring all the arguments above


The Seawych was supplied with a simple metal main sheet horse that spanned the back of the cockpit.

The mainsheet tackle consists of a single block with a "becket" attached to the swivelling boom end fitting and a block plus " fiddle" block with cam cleats and swivel at the bottom,

You could I suppose replace the horse with a bridle

or you could rig a system such as this

The topping lift attaches to the other end of the swivelling boom end fitting.

If your boat is still using the original roller reefing system I suggest that you consider, in due course, converting to a slab reefing system


I suggest you join the Owners Association. Link in my signature. You will then be able to ask questions on the members' message board, avoid all the arguments and get answers from people who know the boat or even directly from one of the association's "Technical advisors" Also obtain, or down load, a copy of the owners manual etc etc.


EDIT:

My blocks are RWO but they seem to have changed their range somewhat.

The equivalent blocks will be 03091 amd 03631 in the Barton catalogue http://www.bartonmarine.com/pdf/Barton-Marine-Catalogue-11-2011.pdf although 03631 has a becket that is not needed

 

[RichardS]

To answer your questions and ignoring all the arguments above

You could I suppose replace the horse with a bridle

or you could rig a system such as this

Ah Vic - you say "ignoring all the arguments above" and then post a solution which is virtually identical to mine ...... except that your solution will, I suspect only provide a positive fixture on one tack whereas mine is secure on either tack.

Richard

 

[VicS]

Ah Vic - you say "ignoring all the arguments above" and then post a solution which is virtually identical to mine ...... except that your solution will, I suspect only provide a positive fixture on one tack whereas mine is secure on either tack.

Richard

Sorry I did not see your diagram. Just something about Vs and upside down lasers.

What I suggest I dont much like but is a 3 part extension of the 2 part tackle on my dinghy .

The sheet can be cleated off securely on either tack but I cant quite get my head around whether of not the unequal pull of 2 parts on one side against 1 part on the other will be a significant draw back or not. I think probably not compared with the standard system with a freely sliding traveller on a horse because with a bilge keeler like a Sea Wych ( it's not the highest performer !) you really don't need to centre the boom and you can't with the standard horse arrangement anyway. Normally over the quarter is about as far as it comes in. I think my suggestion will probably still achieve that om both tacks.

i suppose it could be balanced by making it into a 4 part tackle with 2 "parts" on either side. The drawback then of course will be approximately another 13 or 14 ft of rope.

Maybe the bridle idea is better. We have that on the Puffin.

 

[lw395]

I reckon if you used the 3 part system as drawn, it would be slightly better on one tack than the other for a given amount of kicker. It will be fine. I can name boats that race like that and do more than OK.
Probably nicer to use than having a jamming block moving about on a rope bridle.
4:1 is a lot of friction for a smallish boat.

 

[William_H]

Firstly referring to a laser main sheet system is not help full. Yes they were made in many thousands but to a very strict standard. ie all boats identical. The original system is not much good but remains as a part of the one design. You are not permitted to improve it.
As Vic says Wych it is not a performance boat and yet you might want to get the best out of the mainsail.
The rope bridle system may be commensurate with the performance and design of the boat especially as I think it has a small main sail and all the real work is done by the jib.
I would agree with Vic that slab reefing is far better than roller reefing for you.
Now to waffle on about main sheet systems which are probably inappropriate for you.
The idea of a main sheet and traveller system is to enable the shape of the main sail to be controlled. This means you need control of the pressure downward of the boom on the sail. and to locate the boom and the sail closer or further away from the centre line of the boat.
Now it is fairly intuitive that the closer the boom is the centre line when reaching or beating the tighter the angle of attack to the wind. Closer means more sideways or heeling pressure but also able to hold its shape in beating into the wind.
Consider however that if the boom is allowed to rise it enable the top of the sail to fall away to lee ward. Pulling the boom down tightens the leach and pulls the top into line with the middle/bottom.
Now allowing the top of the sail to fall away can be good to reduce heel but at other times makes that part of the sail ineffective. So ideally you want to be able pull the boom down while allowing the boom outwards when running or reaching. But to allow it to rise and ease the pressure in the top when beating or reaching to reduce heel.
It is especially desirable to pull the boom down but out when running as a boom that can rise a lot can get what is known as a Chinese gybe where the top of the main sail has gybed but not the bottom. really horrible.
(many claim the term means a viscious gybe with round up out of control)
A boom vang is used on many boats to pull the boom down but not impeded its position either near centre or right out.
They can work well on dinghies and some boats but I think like mine the cabin top is high not much room under the boom
for a vang tackle. The vang can pull on the boom from well aft of the gooseneck but then the angle is no much good tending to pull the boom forward into the gooseneck rather than down. Move the attachment forward and you are pulling the boom down but with so much leverage to the aft end of the boom where it matters.
IMHO a vang is hardly more than a preventer stopping the boom from rising too much than a serious sail control on our kind of boat.
Now a proper traveller system has a track along which a car runs across the cockpit. The main sheet attaches to the car. The car is controlled by 2 tackle systems to locate the car ie on centre above centre or below centre.
So you can let the traveller car out to leeward as far as possible when running but still pull the main sheet down to keep the boom down. Also can pull the mainsail off the shrouds to reduce chafe.
Or you can pull the car up to windward of the centre when beating to get the boom closer to centre line and still be able to release the main sheet in a gust to reduce pressure and drive form the top of the sail.
Now you can attach the main sheet to fixed central point so when you pull the main sheet in you pull the boom to the centre and down and when you ease the main sheet you allow the boom to swing outwards and also it is free to rise.
Many boats down the ages have managed with this system but you can do better.
The system using the solid horse is better in that that the boom can be out but still have some downward pressure. But you can not easily force the main sheet bottom block to the centre or even up above centre.
The rope bridle arrangement depending on how tight it is is a compromise between the 2.
Then there is the problem of a transom mounted rudder and the tiller swinging across the aft deck. A solid horse or bridle enables the main sheet to be attached at the back of the cockpit over the tiller. Bare in mind that with roller reefing you must either use a claw around the rolled sail and boom or easier attach at the aft end of the boom.
So if you go for slab reefing you can attach the main sheet further forward. Mine attaches near the middle of the boom meaning less rope needed for main sheet but greater forces. The traveller is at the cabin entrance which I like as i can better reach forward from the tiller when single handed or have crew operate it. A sheet at the stern means only the helms man can operate it.
So I suggest you use a solid horse if it is fitted or a rope bridle just to get you out sailing. Both have a block under the main sheet block to enable it all to slide along the bar or rope. It will work ok. But I hope I have been able to touch on some of the compromises for cost saving and other reasons that make a simple system less than best. How much difference will a sophisticated ssytem make to you performance? Probably not much. good luck olewill

 

[ghostlymoron]

The layout shown in your diagram is the mainsheet arrangement used on the Mirror Offshore which is renowned for its sailing performance. I'm struggling also to get my head around the 'non-symmetry' of it but because the rope is continuous, it seems to me that the tension in each leg must be the same but I can't follow the analysis any further.

Ah Vic - you say "ignoring all the arguments above" and then post a solution which is virtually identical to mine ...... except that your solution will, I suspect only provide a positive fixture on one tack whereas mine is secure on either tack.

Richard

 

[VicS]

The layout shown in your diagram is the mainsheet arrangement used on the Mirror Offshore which is renowned for its sailing performance. I'm struggling also to get my head around the 'non-symmetry' of it but because the rope is continuous, it seems to me that the tension in each leg must be the same but I can't follow the analysis any further.

ITYWF that because the tension in the rope is the same throughout its length there will be twice the pull on the boom on one side as there is on the other side.

 

[lw395]

ITYWF that because the tension in the rope is the same throughout its length there will be twice the pull on the boom on one side as there is on the other side.

One one tack there are two strands pulling down and one pulling down and in.
On the other there are two strands pulling down and in, and one just pulling down.
So to get the sail 'in' the same amount, the boom will be pulled down more on one tack.
This may just mean the kicker has less tension on it. Or it may mean the twist cannot be made optimum in lighter airs.
I can't see it preventing the boat from getting from A to B reasonably well though.

 

[leachs4]

Thanks guys, this has given me a lot to think about.

VicS thanks for the link to the SWOA , I have submitted a request to them this morning.

 

[ghostlymoron]

But, if there were twice the pull on one side, the boom would move to the opposite side. It must reach a position of stability where it stays in position.

 

[Lon nan Gruagach]

But, if there were twice the pull on one side, the boom would move to the opposite side. It must reach a position of stability where it stays in position.

The sail will do that bit, just on one tack the sail has to do more.

 

[Billows]

Now allowing the top of the sail to fall away can be good to reduce heel but at other times makes that part of the sail ineffective. So ideally you want to be able pull the boom down while allowing the boom outwards when running or reaching. But to allow it to rise and ease the pressure in the top when beating or reaching to reduce heel.

I was always taught that to reduce heel you flattened the sail when beating by putting the traveler to leeward and pulling down the boom.To allow the sail to twist would increase heeling.

 

[William_H]

I was always taught that to reduce heel you flattened the sail when beating by putting the traveler to leeward and pulling down the boom.To allow the sail to twist would increase heeling.

Pulling the sail down would be part of flattening the mainsail but also includes tightening the out haul and halyard and even bending the mast. It is the actual releasing the traveller to allow the boom to move out from centre line that alleviates heel. (by reducing angle of attack) Giving twist by easing down pull of the boom should allow the top of the sail to fall away reducing heel but in giving the main more camber will tend to worsen heel. Pulling on the back stay in a fractional rig can allow the top to fall away reducing heel but only with dramatic mast bend. olewill