Metal mast and one string questions

08/12/2009 09:31:29
fribbs
I have just bought my first Merlin, 3381, a Jon Turner NSM4.  It currently has a metal hog stepped mast.  I will probably float about mid fleet, on a good day, so is it worth me considering a carbon rig?

I'm also fascinated by the term, one string. What is it exactly and could I convert my boat to be one string?

08/12/2009 09:52:27
Mags
You may think the performance increase of a carbon rig is negated by your abilities, and I guess that is true, but it means a heck of a lot less weight floating around at 20ft up, which makes for an easier life. But it is a lot of cash too....

'One-string' is a complex rope system which allows one bit of rope to adjust 5 control lines simultaneously. But really there are two ropes - one for RIG UP, one for RIG DOWN.

http://www.merlinrocket.co.uk/library/misc/one_string_raking_rig.htm
08/12/2009 09:54:36
Mags
P.S. If you've got a hog-stepped rig at the moment, you'd have to do a deck-step conversion on your boat. With a 33xx number it would probably be OK, but not ideal.

However, if you like boat DIY...go for it!

Use the forum search facility to look for past discussions about deck-stepping.

08/12/2009 09:59:42
fribbs
Thanks Mags

I'll have to wait for my association membership to clear so I can look at the one string thing.

I hadn't considered the weight issue of carbon v alloy, which is surprising as I race a Thames A rater, where the move to carbon has made a huge difference. Well it would with a 45' mast!

08/12/2009 10:07:58
Mags
N.B. The weight advantage of a carbon rig is not wholly about the all-up weight of the boat - its about not having a chunk of heavy aluminium waving around 20ft up in the air, giving you more to hike against etc.

Also the carbon masts have 'gust response' where the top flicks off a bit and cushions you from the full blow. Makes life a bit nicer.

Or so I understand it....not having one of my own...grumble moan etc

08/12/2009 10:09:34
Mags
The link above, and the photos in the gallery (see link at bottom of that page) are open to anyone. Its only the article on conversion that is password-protected as it was taken from the magazine.

08/12/2009 10:32:33
fribbs
Hi Mags

I understand the righting moment/capsizing moment of the mast. We take the rater to the Horning Three Rivers race, where we have to drop and raise the mast four times to go under bridges. The effort required to raise a metal mast is considerably more than to raise our carbon mast.

08/12/2009 10:45:52
WP
You wouldn't have to deck step your boat just to have a carbon mast , we have at least 4 hog-stepped carbons at Tammy, they would need to be sleeved up to the Spinnaker eye though....
If you want to go the whole hog with ful raking etc then it needs to be deck stepped.

08/12/2009 11:01:19
fribbs
I think that this is something that I won't rush into!  I'd like to keep her 'near to original' as practical, while making her fun and easy to sail.

A carbon hog stepped mast sounds like a good compromise, although I think that the first performance improving expenditure is going to be on new sails. Mine are dated 1989 and the jib looks 'tired'!

08/12/2009 11:18:27
Andrew M
Looks like the championship winning Seventh Wave you have there.  In it's day there was nothing wrong with the boat or the rig, the best there was in the 1980's.  A decent set of sails and a big spinny and long poles if not already installed will give you a big performance boost.  I have already been reminded that 3339 has beaten a lot of more modern boats without a carbon rig.  Conversion is not cheap if done well and you wouldn't want to do anything half-baked to this boat.  I think you either keep what you have and make sure the sails suit the rig or spend a couple of grand at least on deck-stepping and carbonising.  Looked at like that, you may consider selling and buying a more modern boat a better option.  I would have some reservations about a carbon mast being hog-stepped with a strut as the mast wall is not as strong with point loads as alloy.

08/12/2009 12:04:10
Jez3645
If you are looking for a carbon rig Kev Berry is selling a superspars second hand for £500. They are like hens teeth so won't hang around long. You will find his details under 3582 on the for sale list.

Looks like it is still in good nick Seventh Wave, as Andrew has said it is a good boat. Personally I would say that if you are going to be driffting about mid fleet you will find more advantage from a new set of rags than all this work on Carbon. Again as Andrew pointed out spending that kind of money on an older boat you may as well have bought a newer one.

Which Rater have you been sailing then?

08/12/2009 12:30:44
fribbs
I bought Seventh Wave as I wanted a Jon Turner boat. I crewed in one of his scorpions, Nelly Welly, and have been lusting after one of his boats since then.  I just want to enjoy sailing it and owning it.  It is in good condition and is being tarted up by Jamie Stewart.  It has carbon poles and a big kite, so all I need are main and jib.

I would only switch to carbon if it was relativly simple and not too expensive, which it obviously isn't.

I'm in the Lady Jane, No 20, Rater syndicate. Our exploits in the 2005 Three Rivers can be found here, then there is a report for each of the subsequent years.

http://www.thamessailingclub.co.uk/E42FF/About_TSC/Archives/2005/News/Three_Rivers_Race_2005.aspx
08/12/2009 13:03:09
Jez3645
I know the one. Did you not have some nice new decks put on her a while back?

The Turner boats are very nicely built. Never had one myself, always had Rowsell and Smart.

Good luck with it and most of all do enjoy it. Merlins are a great boat to sail and a great class to be part of (as you may know from the Queens Cup at Bourne End!).

08/12/2009 13:37:53
fribbs
Yes, we had the false floor removed and new decks about four years ago.  We had the hull re furbished two years ago and new sails lasy year.  She's under a programme of continual improvement.

Do you go to Bourne End week?

08/12/2009 13:40:23
ChrisJ
When someone was trying to pursuade me to get a boat with a One-String, the answer I got about the benefits of a one string raking system were:

As the wind picks up and you feel yourself getting over-powered, then you:
- let the puller off
- let the jib halyard off (more than is required)
- tighten up on the shrouds
- tighten up on the lowers
- tighten up the jib halyard to maintain the correct tension
- tighten up on the kicker.
And you do that while controlling the boat in the race, avoiding other boats, over the waves, and before the wind drops again! You also have to do it around the windward mark, and reverse the process around the leeward mark - just when your crew is hoisting and dropping the kite.

Alternatively, you undo the rope saying "rig forward" and pull in on the rope saying "rig back" - and that’s it!


I haven't sailed a Merlin enough as yet to know whether it really is that easy or not!

08/12/2009 14:06:31
Andrew M
It's not really that bad, you let off the jib halyard to the appropriate mark, puller is not on anyway as beating.  Pull in shrouds till leeward shroud snugged up, tighten lowers to the mark, adjust kicker a bit if needed.  All done by crew with string accessible when hiking.  I have only 3 marks - upright (light), powered up, and full rake.  One advantage of the Jon Turner boats is that they were very well fitted out with quality cleats and blocks, I have not had to replace much and the boat is now 16+ years old.

08/12/2009 15:53:58
Jez3645
Yes, I have been doing BE Week for about 20 years in the Merlin, although I missed it last year due to Honeymoon commitments, My wife and I won it in 2008. Always loved the Raters to sail and to watch. I know allot of the guys and gals from Thames too.

08/12/2009 15:54:33
Jez3645
Sorry meat last time not year!!

08/12/2009 17:57:30
the gurn
Fribbs - I dont have a one string system and it doesnt affect my performance at all!

08/12/2009 23:00:18
deck v hog stepped
Can someone please explain why a one string won't work if you are not deck stepped?  Is it that it has not been tried as the trend of the leading boats is to be deck stepped, or is there something that prevents it from working?  

If it theoretically works then why could you not do it?

Why deck step rather than hog step apart from the weight saving as the mast is not measured? Since going to carbon masts has a leading team tried hog stepping at all?

08/12/2009 23:57:16
KM
One major difference between hog stepped and deck stepped is the rake angles achievable from a hog stepped boat are limited by the mast gate - to rake back as far as a deck stepped mast can, would probably result in the mast coming out of the slot.  
I'm guessing that because the mast can't/doesn't usually move through such a range, adjusting it on the move isn't such an issue (not with quadrant levers anyway!)
Hog stepped masts not having lowers means less to fidddle with anyway.
Presumably you could put muscle boxes on jib and shrouds and somehow link them.

I'm sure to have missed something ..... rig tension on high tank boats?

09/12/2009 07:18:43
Chris M
It's more a case of you don't need a one string becaus you dont need/can't use large amounts of rake with a hog stepped mast.

09/12/2009 07:36:45
Measurement Man
The reason why the raking isn't as effective on a hog stepped mast is to do with the point of rotation of the mast foot.  The higher the rotation the more effective the system.  Taken to an extreme, you have Dangerbatt which has a stub mast and the 'mast foot' rotates from a point just below the gooseneck.

With a hog stepped mast,the rotation is just not enough to make the expenditure on one string conversion value for money.

GGGGGGGGGGG

09/12/2009 08:44:49
Richard Battey
The actual work involved (woodwork) to convert to deck stepped is very easy as I have done it on my very old boat MR 908, the only difference with my boat is that I don't have an adjustable rig as the hull would not take the loads and would fold like a clam. 3381 has a low bouyancy tank and therefore is ideal for conversion. The cost of conversion is in all the fittings required to create the multitude of pulley systems. Alternatively you can get it done professionally as there are plenty of boat builders out there that can do the job, just depends on your location? The other good thing about deck stepping is that if you want second hand kit then pretty much all that is available on this site is for modern rigs so it spreads the net in terms of choice. Good luck.

09/12/2009 09:45:33
Stringing along on a Wednesday
This might be a stupid question from someone who will never get to understand the forces at work on masts but if you have a stub mast which is in fact the lower portion of the mast from the hog to above the mast gate and an arrangement of hinging at that point would that not allow more mast rake?  Or perhaps that's what GGGGGG is saying is on Dangerbatt?

09/12/2009 10:44:17
;)
Yes, I think dangerbat is used as an example of alot of rake, vs hog stepped = not much at all

09/12/2009 13:02:58
John 1201
You can of course put a raking rig on a hog stepped boat!!
With a deck stepped mast when you rake the mast and shrouds all stay more or less in unison and the spreader angle remains the same, however, with a hog stepped mast the point of rotation is now below the shroud entry point. As you rake the mast the spreaders now effectively move forward with respect to the shrouds.
I probably have not explained this properly but unfortunately when you rake a hog stepped mast the spreaders will be effectively move forward of the line of the shrouds stiffening the rig the opposite of what you want to achieve and tend to negate the effect of raking.

09/12/2009 14:31:33
Mags
Good point made above - the main cost of deck-stepping is not the carpentry, but the chandlery. You're going to need more than 20 ball-bearing blocks, for starters...

09/12/2009 15:00:14
Ancient Geek
For those requiring "string" or rope may I commend 
The Nottinghill Rigging Co.
0208 144 0659
07988 437102
Excellent value friendly efficiency.

http://www.thenottinghillriggingco.com/
09/12/2009 15:39:59
Andrew M
My back of envelope calculations for deck-stepping even if components sourced 2nd hand:

Mast £500-£1300
Fittings and rope £500
Mainsail £500
Woodwork £800 or DIY

unless anyone can give a more accurate figure.

I put quite a bit of work into Supernova, 2315, a few years ago with adjustable shrouds to allow rake adjustment on the move. It never really worked in the same way as a deck-stepped rig and very likely for the reasons John gives, you couldn't get as much rake adjustment anyway and as the mast went back the spreaders straightened the middle of it preventing proper depowering.

09/12/2009 20:18:22
Andy Hay - 3626 Business as Usual
Kev Driver did Enchantment for £600, plus repair to 2nd hand carbon twig (Superspars, bought for £80) costing £300. Blocks, rope (replaced the high load bits after a season), cleats, etc. about £500 unless you have a pet chandlery or work for one. Main & jib to suit bought through a trade contact - not going to reveal that cost! - plus square top hoop (home made in carbon, cost about £200) as you'll need this to get the modern sails to work. Not cheap. 

Did it make a difference ... yes

Would we do it again ... yes and there is a good reason for this:

The upgrade was part of a programme building up to getting a newer boat. If we had just bought a Winder or LIR first off, we felt it would have been too much all at once and probably wasted on us. We had two full on seasons with Enchantment, learning the ropes so to speak, so when we bought Business as Usual, we knew what the strings all did.

09/12/2009 23:58:45
Ben 2529
Hi Fribbs
I am a new member at Thames SC although 2529 sails at Minima - we must have a chat in the bar.
This posting is not for me but I am thinking of putting a hog stepped carbon mast on a vintage boat.
I have found all of this both interesting and very informative so many thanks to all of those who have contributed. The forum really does work.

10/12/2009 11:21:06
Mags
It does when (for once) everyone has stayed on topic!

10/12/2009 15:00:27
Fribbs
Hi Ben

I'll be at Thames on Saturday evening, probably Sunday lunchtime and Tuesday evening. See you there for a chat!

10/12/2009 18:41:13
ChrisJ
Not sure if I agree with the hog stepped mast + more rake + spreader angle comments above.

I feel that raking the hog stepped mast back will move the end of the spreaders backwards in the boat; although the shroud anchorage points are staying the same. Therefore, the shrouds will now push the middle of the mast forward when they are under tension - thus bending the mast more.

Very happy to be corrected....!

10/12/2009 19:54:12
Ancient Geek
Chris, make yourself a crude model with a drinking straw and bits and you'll see that you are not right the effect of rake on fixed spreaders is as the others have said, if the shroud anchorage stays the same.

11/12/2009 13:14:25
Mags
Mainly because the mast pivots around a point 2ft lower than the shroud anchorage points.

12/12/2009 10:15:07
deck v hog stepped
So a hog stepped mast with the hounds 2 foot lower would rake similarly to a desk stepped mast...  But you dont want to lower the hounds as jib luff is controlled by the rig dimensions and you want to keep this where it is.

12/12/2009 11:54:30
Richard S
I think the shroud anchorage points being referred to here are where the shrouds go through the deck. The hounds move with the mast and therefore are not altered by rake.

12/12/2009 20:55:43
Broz
I was going to deck step a mast,but a well known, brand name sail maker talked me out of doing it.
He argued, that hog stepped mast have more control over sail shape and are faster in light winds.
Some classes that sail with carbon masts push the mast forward in strong winds. This is to compensate for the leach sagging of due to the softness of the mast.The sail cloth is stiffer at the top and the leach length varies with mast stiffness.

13/12/2009 13:06:06
Blackie
Chris I'm with you! If you rake the hog stepped mast it will bend the mast more at spreader level and the distance between an imaginary line across the shrouds and the mast will reduce as the mast is raked. 
By stepping the mast at deck level, ie just above the point the shrouds go through the deck the distance between the imaginary line (across the shrouds) and the mast stays relatively constant. So the mast bend stays constant.
As the pivot point of the mast moves up as in the case of Dangerbat then the distance btween the imaginary line and the mast increases. Thus straightening the mast as it is raked...
Draw it!

13/12/2009 21:58:45
John 1201
Further to my earlier post where I mentioned why it is we had decked stepped masts.
There are only two reasons to have a decked stepped one as I said earlier is because with a hog stepped mast when raking the mast rakes the spreaders, although they do move back the speader angle does change and effectively moves forward. In the early days of raking rigs this is what happened and unfortunately with an ali mast the spreader angle moving forward the mast became very stiff.
Note, that by moving the mast pivot point above deck level the reverse occurred and the spreader angle does effectively move back to assist in bending the mast as with Dangerbat. Helpful with the type of Ali mast used at that time but not so important now with flexible carbon rigs.

The only other reason for having a decked stepped mast would be for a rotating mast.

Structurally you would want a hog stepped mast.

With a stiffer Older aluminium mast as found on a lot of old boats you would want the mast as long a possible to help get some bend in it (I have one and would like a carbon).
With river sailing you do not need to use a raked mast as often as it is not quick to sail with more rake than you need, especially if the wind is very up and down.
If it gets so windy you need to rake on the river better to go and have beer!

13/12/2009 22:02:28
Dave
yep on a hog stepped boat bend INCREASES as you rake, hence furballs / 470s etc winding winding thier spreaders forward as they rake to keep the bend constant.

14/12/2009 03:00:45
Novice
Surely if when the mast is upright, and the spreaders are in front of the shrouds, the mast bends normally under shroud tension.  When the spreader tips come aft of the shroud base points, the mast bends the other way - wants to invert. I thought releasing the pressure on the spreaders (420s etc) would allow the mast to bend more normally and not try and invert it at the spreaders.

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