Mainsail design

03/01/2019 18:16:19
Richard Saunderson's wintertime and nobody has yet made the annual suggestion of lowering the minimum weight of the hull!! So how about a discussion on fathead mainsails instead? Some classes have moved in this direction and there is little doubt that they offer good gust management. We have expert sailmakers amongst our members and it would be interesting to hear their thoughts. Almost inevitably I'm going to get the "If it ain't broke....."  responses but it would be nice to have some considered and informed debate on whether this could be an avenue worth exploring.

03/01/2019 20:26:15
My response is considered, and I believe informed.  

The class is successful as it is.  Such a change would reward light weights even more- carbon rigs and wider boats have already reduced the competitive all up weight.  The option essentially already exists in that there is a choice in rig height.  Taller mast - fatter head.  I think that the rule works. 

03/01/2019 23:21:42
Regardless of potential performance pro’s and con’s, the key attributes that make the Merlin Rocket image won’t and shouldn’t ever change; clinker hulls and pointy mainsails included.

04/01/2019 06:24:40

Maybe this might be a good point to start the discussion on how to help future prof the Merlin. First let’s deal with the myth. Merlin’s had pin heads main to start with, and the head shape we have today, came about by the rule allowing free roach. It was as far as the sailmakers were able to push the roach with the batten and material technology they had. I will speculate that if they had the materials we have today the boats would have had square top mains.

The average man in the UK (I was told you should never talk about a woman’s weight) in 1950 was 73kg but today it is 80kg. There height has also increased as well. We can debate the rights and wrongs of people getting heaver but for the majority of the population it is just realty. The other big differences we have seen is the boats have got wider (more leverage) and we are able to deal with power by our wonderfully raking system.  Which has led ,to much faster all-round boats that are now able to be sailed by much lighter crew combinations.

With this in mind and taking careful consideration to the fact that many of us like to sale with young ladies. It might be an idea to look at first off. Changing the top batten measurement to allow the out board end to be pushed up 50mm that would give a little more head area, as well as a bit more roach, but would maintain the general shape of the head to keep the distinctive look of a Merlin mainsail. Secondly it would need a change in the formula but the best way I can describe my idea is if you could keep your main foot length that you had when you had a behind the shoot jib tack but we could have a jib that was a bit bigger. At the moment our two normal sizes are 2.7 (tack back) 3.02 (tack forward). If we went to 3.5 in the jib and the same length main foot but pushed the top batten out 50 mm we would end up with about 1 sqm extra of sail area .The third and final thought is increase the hull weight to 100kg for all new boats. The combination of these three things may help the class deal with the long term problem of crew weights appealing to the wider public.

04/01/2019 07:47:36
I think that the way to help heavier people is to make the boat harder to sail rather than to add sail area.  The boat then becomes less tolerant of mistakes and light weights have to be “better” to survive.  The Merlin hull is not difficult to sail and with a modern rig the crew weight has dropped.

Keep it as is!

04/01/2019 08:36:07
John Fildes
Ok so how do you plan to make it harder to sail if you are going to keep it the same? 

04/01/2019 08:43:32
John Fildes
Ok so how do you plan to make it harder to sail if you are going to keep it the same? 

04/01/2019 09:03:28
Gareth Griffiths
You should have seen me on Sunday John, fancy dress hunt cup. Fancy dress definitely makes a Merlin harder to sail...

04/01/2019 09:14:27
And make the boat look like a skiff? Why?

It works as it is, I'm with Olly on this one.

04/01/2019 13:47:12
Gareth Griffiths NHRC
I don’t think you would get as much benefit out of a square top as you think. Current main is already pretty square.

I think hull shape, rig design and foils for big guys have more influence. 

As with any class if you are at the larger end of the crew weight scale, get a stiffer rig, higher aspect foils. 

More luff curve, more hull rocker will do more for your performance than a square top main

04/01/2019 15:21:37
Stuart Bates MR3615
I think that a change to the total sail area would be easy to manage, but provided that we keep the current 'look' of the class.
As one of the heavier teams I wouldn't be adverse to this, given the current trend towards Bow-Tack jibs allows for more space in the fore-triangle and making the main larger by easing the measurement rules would be easy to implement.

05/01/2019 13:19:53
Roger Cole

We had all this bonkers nonsense about increasing the sail area many ,many years ago . People were

worrying that heavy crews were being outclassed.  At an AGM at Weymouth back in the 1980's Phil

Morrison spoke very eloquently  on the subject.  Basically,  if the area is increased the lightweights  go
even faster downwind and plane even earlier and with modern rigs can depower to remain competitive
upwind.  And this was when everyone was using alloy masts!  He said (and I totally agree) that the only way to  help  heavier crews is to increase the hull
weight so that the human component is a lower percentage of the total sailing weight . 
Be very careful what you wish for! 

05/01/2019 16:34:03

Great points Rodger which is why I have suggested a very small increase in weight but with most of the  gain is in the jib area, this will only really help the boat upwind as it is never fully utilised down wind. This may help balance out the fleet by being an advantage to a heaver crew up wind and yes the light weights should make up any losses down wind.

06/01/2019 12:32:43
Roger Cole

In reply to the last post by Albatross , To update the sailplan to new rules we would presumably need to purchase a new suit of upwind sails at a cost of £1100--£1200.  This is more than many club sailors boats are worth.They are therefore unlikely to upgrade. Are they supposed to yacht around  in handicap fleets with a totally uncompetitive boat ? The class association has been churning out the same club racing age adjustments for years as the class PY continues to drop. My 43 year old boat is much loved and maintained in immaculate condition but sadly hasn't got any faster!    Will average "clubracer man" spend a shedload of cash  to upgrade ?-----no.    Will he become increasingly cheesed off with being totally uncompetitive?----Probably.    Not a good recipe for  encouraging club sailors to join the class.


06/01/2019 13:37:22
Has the competitive weight range really changed?
Teams between 19-24 Stone have been winning on the circuit in recent times, in any wind strength and water category. 

Forget weight and trying to adapt the boat; just put the time in on the water!

06/01/2019 17:01:25
To keep the rig the same is the ideal choice. Not all in the class are cheque book sailers. A lot of us have spent money on rig upgrades on older hulls and nurture a good suit through multiple seasons. If the class went ahead and made significant rig changes I’m sure a lot of owners would walk from the class and go elsewhere. The rig is great as is. Looks great as is. Very distinctive main sail. If I want to sail a square top I would go back to Skiff sailing and then spend even more money. No thanks. 

06/01/2019 20:45:10
The Merlin Rocket.

I get the feeling this might need to updated, as the description may no longer be relevant . 

The Merlin Rocket is a 14 foot dinghy sailed in the United Kingdom. It is an active class, now with over 3700 boats built.[citation needed]

The boat designed around a box rule, meaning that all class boats need to be within a certain length and width, but can be any shape. This allows for quick modernization of the class. The great advantage to this is quick adoption to new technology and the ability to change a boat to a person's weight and ability. Although the rules allow for many sail plans, many modern Rockets have similar sails. Most have a high batten allowing for a large roach in the sail. Although the rules are open, they are not unlimited. Use of a Trapeze is forbidden in this class.[citation needed]

06/01/2019 22:37:50
Roger Cole
Too  true --the wickipeadia description certainly needs a drastic update!  "boats can be any shape"!!! Mynext design will ignore the rise of floor rule,  the max. plankwidth rule ----"many sailplans", so I'll have 120 sq.ft.    And as for a "PY of 102".----Thanks , that will be fine.                  We are governed by the class rules, not wickidescriptions.

07/01/2019 16:13:26
Hmm, if Phil Morrison says bigger sails favour lighter crews how about smaller sails!  

In all seriousness Roger, why should your much loved 43 year boat be competitive?  I wouldn’t expect a 43 year old RS400 to be and they are a one design class.  Enjoy your boat for what it is, a beautiful work of engineering, but don’t complain it’s not competitive against the latest developments. 

07/01/2019 19:11:42
Roger Cole

I am in no way suggesting my dear old boat should be competitive against the latest creations.  We had our day in the late 70's and early 80's until she was out classed by  (much) newer  designs/ advanced materials/ technology.   I would ,however, like to club race in the handicap fleet at my local club on a fair basis. As the PY number steadily drops ,the age allowance additions have remained the same ever since they were first introduced ( the class PY at that time being1006 ) This means that the age related yardstick (+40 for my boat) has dropped from 1046 to 1006 which is quite an ask for the old girl.

My great concern  is that there seem to be a number of older boats  with owners who enjoy a sail at their home club, don't  really want to travel and have a perception that the class association has little or nothing to offer them.

Having been an MROA member continuously since 1976  I subscribe to the view that the assoc. is working to promote and protect the interests of the class as a whole. However, as one who due to a variety of commitments, does not participate on the open circuit I begin to wonder if they have a point. 

07/01/2019 20:14:27
Rod & Jo Sceptical
We still talk about our old Merlin,- the one from 1964, or the 'new' one from 1975. Of course we don't expect to be competitive;- we just like our boats, and are proud to belong to this great class.
We have seen periodic discussions on weight reduction, increase in sail area etc. going on for over 40 years, but IMHO the MROA has got the balance between tradition & evolution exactly right,- leading to what is a stunningly successful class today; we've wanted to visit Salcombe again for the last two years but couldn't get in. Compare that with N12 class (we sail also) who are struggling with numbers because their more radical evolution has split them asunder.
I share Roger's frustration with the rigid link of older boat PY to new ones, but if we had any pretensions on winning I think we'd have got the message & given up decades ago anyway.
If you want a craft that is overpowered & just goes from one spectacular capsize to the next, then change classes; leave Merlins as they are,- or more precisely as they have come to be. Sure they will probably evolve more, but for the moment there seems no reason to rush it!
Rod & Jo,- French contingent.

08/01/2019 10:38:38
New Merlin Rocket has been spotted....

08/01/2019 10:39:03
New Merlin Rocket has been spotted....

08/01/2019 10:39:33

Try this.

08/01/2019 10:40:10
Roger Cole
  A correction to my last post----Over the years ,the class PY has fallen from 1006 to 980.  This of course  gives an age  corrected  yardstick of  1020  ( +40 ) for my boat.    Maths never a strong point!  But still a big ask against a Solo fleet that includes  an Olympic gold medallist (we did used to narrowly win sometimes, but now we don't. )

08/01/2019 10:41:13

Try this.

08/01/2019 11:32:57

Try this.

08/01/2019 15:49:10
HI,  Why does the forum make multiple entries against your will at times?

09/01/2019 09:46:15
Looks good, but I think out of class. It's too short.

09/01/2019 13:12:14
Andrew Mills
I'm sure if someone wanted to build a 12' Merlin that satisfied the rise of floor & plank width constraints it would be within the rules .
A big bowsprit  assymmetric & a couple of trapezes somewhat more of a problem


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