The Specifications, Rules and Regulations for the Dublin Bay Sailing Club Mermaid, otherwise known as the ‘Blue Book’ is available at http://www.dublinbaymermaid.org/downloads/MermaidSpecification2007.pdf.
What are your views (click reply above right)?
My boat has being out of the water for 35 years and needs a major refit one of the issues is the position of a single chainplate on each side as opposed to 2 on each side which are currently on the boat.
1 Should i change to one plate each side ?
2 What are advantages disadvantages of both set ups ?
3 What is the idea position for single plate ?
Alan. I suggest you check out Roger Bannon’s Tuning Guide, now available for download on the http://www.dublinbaymermaid.org/index_files/Downloads.htm
Cheers will print it off, some more bed time reading.
Alan
Boom under construction
At the AGM on 23rd February Boom Construction is on the agenda.
What are your views?
Add your comments by clicking on Reply above right. Ensure that your name and/or boat is identified in your comment. Anonymous and offensive comments will be removed.
Having broken 2 booms which have probably cost me a couple of Champioships I am interested to see that a debate about boom construction has been initiated.
Following my last broken boom in Sligo I decided to fabricate one to a slightly different specification which not only complied with the rules but I believe is much stronger without incurring a significant weight penalty. I have yet to try it out as the boat has been stored since August 2009.
Basically I fabricated it from 1″ planking rather than 3/4 ” as per the spec. The top of the “T” section is made from 2 lenghts of timber which are 1.25″ wide and .75″ thick which are glued each side to the top of the “I” section which is made from 1″ thick timber. The “I” section is in fact two .5″ pieces laminated together for extra strenght (probably over the top and unnecessary). The “I” section was then tapered down to .75″ from below the “T” profile. .It is a little bit heavier (probably no more than 1Kg) than my previous booms but it is much stronger. It needed a bit of fiddling to fit the goosneck which is designed for .75″ timber, so a bit of rebating was required.
I am confident it measures as there is nothing in the rules to prevent using thicker than specified timber and the “T” profile has been maintained.
I do not believe it is necessary to change the rules as I believe this construction approach solves the problem within the existing rules and maintains the existing boom profile which the traditionalists should appreciate.
This sounds like a good strong boom and if it measures all the better. I’m going to look into this and make one for myself if you don’t mind Roger.
I had a boom go BOOM as well ,it broke probably where all of them go ,at the kicker bracket.As the mast & boom colours & I guess age ,matched,I didnt want to have the new one look too fresh,I can & do in my work make furniture & match wood colours ,but I liked the “maturity” of the original boom,so ,having a spindle moulder at hand in my workshop,( this is basically like a massive floor mounted spindle moulder standing upside down ,but with a 7 hp motor,& can take 300mm cutters-lovely but lethal-)
My boom was about 18mm thick on the vertical section so I hollowed out a 12mm slot x 50 mm deep ,leaving 3mm of the original timber either side of the boom.
I then machined a piece of European larch with a 1mm clearance for gluing & fitted that inside the original “shell”.
One addition I did make as the top flat part of the boom had cracked ,was to shoulder the “I” section & cut a 6mm dado into the flat section to give me a staggered glue joint & a mechanical fix as well.
So boom is repaired and looks as if it was never touched !!
Here is a tip that may help in maximizing the timber strenght in the boom ,ideally start with a heavier piece of timber rip it down the middle -Top & Tail it- IE when you have the piece halved ,turn the pieces so that the top end of one side is meeting the bottom end of the other piece,this means that the younger part of the tree is now attached to the older -lower part ,the next trick is to take the two pieces and put their two OUTSIDE faces together & glue /epoxy as this reverses the grain of the original,this should give you a boom that is four times stronger & much stiffer than the original piece of wood,we used do this with timber masts years ago.
Even if you cant do this,housing the “i” section into the top will give you much more shear & twist resistance as well as making the joint way stronger.
Addendum ,I meant to say ROUTER when describing the spindle moulder E
Martin Smallwood comments: Last summer made 2 booms from popular/tulip wood in a laminated construction for Sea Fox and Argo, kept within the measurements. Tested them for springing and were surprisingly quite stiffer and stronger and with no weight difference.
Martin,I was very interested in your use of Poplar for the booms ,as I wouldn’t have really considered it for exterior use,as it’s normally used for internal joinery & wood turning due to its close grain,but checking out its characteristics ,it gives a much better rating for final seasoned hardness & greater split resistance by far than spruce.Also being a very light timber it would be ideal. Caveat any scuffs,dents etc have to be sealed-WHEN DRY- or it will start to rot.
I’d be interested to hear from guys who make boom/masts as to which wood you use,as my boom seems to be spruce,the mast is definately spruce,but a much higher quality.
Reason being ,that when my brother – in – law was building a 20 ft day sailer in Ashbourne in Meath he found it very difficult to find a supplier of European Larch,he contacted Coillte ,they didn’t have any & told him to ring around the local big estates,which he did & was lucky to get some seasoned planks,but they were scarce.
I use Eur Larch & find when air dried ,it is VERY hard & practically impossible to break across the grain,watch out if you try to break it with an axe for firewood as it can bounce the axe back at you in a flash.
NB You might think I’m being a bit fussy re calling it European Larch all the time ,but the other more readily available species is Japanese Larch warrants being kept as far away from as the longest barge pole you can find.The Coillte guy rightly advised the Brother -in-law that it was akin to Ruhbarb,hard on the outside ,but apply water & it goes soft from the inside !!
Looking forward to any comments,
BTW, I think the Tech Forums are a great idea !
ROGER BANNON comments: I have been thinking about repainting “Endeavour” as it is nearly 12 years since she last experienced a paint brush or spray gun. To be honest it is mainly the interior that needs attention as the rest of the boat which is coated with 2 pack polyeurathane of one kind or another is still in astonishingly good condition.
I have heard that “soda blasting” is a very gentle, quick and thorough way of removing conventional paints from wooden surfaces. Sounds to good to be true? I believe classic boat restorers in the UK regularly use this technique but I wonder if it can be used on soft timber like silver spruce. I would hate to have to scrape off paint using Nitromors and other chemicals which I believe do terrible harm to the timber, no matter how well you try to neutralise them. Apart from anything else it is an awful job and I swore I would never do it again.
has anybody any experience of this? If so how much did it cost?
Hi Roger,
I was contemplaring using this Soda Blasting system,but couldn’t find anyone here in the SouthEast that had one.Waterford city hire shops have even stopped hiring out sand blasters due to health & safety.We still have one on hire here in Dungarvan though.
The only soda blasters i could find were in the North.
I did a bit of research & found that its very expensive & cleaning is a problem afterwards.
I have to do te same job on Alita,and like you wouldn’t use nitromors inside a hull.
I am going to try Owatrol PREPDECK tomorrow,I have used it on stained & treated decking already to good effect ,but never on caked on varnish,its a natural product & water soluble,I’ll post as to how I get on.
There is another homemade solution,it requires making a cornflour paste & adding caustic soda & then apply to varnish ,it is used widely in the US to remove paint from fibreglass as it doesnt affect the gelcoat,I’ve tried it recently on a GRP boat I was renovating,it works fine but a slow job.
Regarding nitromors,for those that may not know,dont use it on GRP as it eats gel coat.
Regards
Eugene
Roger we have white smoke – literally- !!!
Tests done with the Owatrol Prep Deck only worked where the liquid pooled ,but would be expensive on vertical surfaces.
As I had already tried the Caustic/ cornflour paste I wasn’t impressed with the application,you need a medium to hold the caustic in suspension & damp ie active ????
Then it hit me NAPALM !!
During a misspent youth we had experimented with various incendiaries for the crack & one of the ways to imitate napalm was to add a little drop of diesel for prolongued burn time and a nice drop of washing up liquid to the mix to make it stick!!
I added a half cup of cold water to a PLASTIC container mixed in 40% by volume caustic soda ,stir well wirh wooden spatula -normally known as a stick- add about 30% by volume washing up liquid ,then with synthetic bristle paint brush apply liberally ,working into timber until you get a nice foam up.
I left it for 24 hours and both varnish & paint came off in a paste,leaving bare wood.
Wash down timber with plenty cold water ,powerhose preferrable,then allow to dry completely,this could take a week or two depending on conditions.
The next stage depends on what finish you are applying,I’ll be using Owatrol Deks Olje D1 which will “re- hydrate” the wood ,but if you are going to use varnish then apply neat vinegar to the wood to neutralise & allow to dry out,give a wash out with white spirits & then dilute your varnish with 30% white spirit & then apply as directed.
WARNING !!
ALWAYS put caustic soda INTO COLD water NEVER the other way round !!
USE PLASTIC & WOODEN utensils
Wear Eye protection & rubber long sleeved gloves/gauntlets
Have adequate ventilation
Buy your washing up liquid & vinegar in LIDL !!
Apparently wallpaper paste works well as a suspension medium too.
Happy stripping
Eugene Burke ,Akita No 85
Soda Blasting is kind to the timber, particularly if used wet but expensive and needs careful cleaning afterwards. The guy from the North hasa lot of experience of stripping wooden boats and classic cars. The advice I got was to ensure the operator had previous xperience of working with wood as otherwise the finish may be left a bit grainy!
Caustic soda does not remove the old pintk primming and UCP undercoating systems we used to use.It tends to disolve the pink priming into the grain of the timber and leave awful dark patches.It has no impact on UCP except to dull the finish and turn it slightly white and powdery looking.
I think I will give the soda blasting a go but it will cost about €500 which is a bit steep. However it is quick and thorough and does not damage the timber provided you power wash the residue gently immediately afterwords and let it dry completely and slowly.
I have strippd the intetrior of 5 boats over the years and I swore I would never do it again.
That is why I have convinced myself the €500 is worth it!.
Can anyone help? I need about twenty size 26 six inch brass or stainless screws for centre board casing, I would appreciate any help. cheers martin
Hi Martin,doubt if you will get that size screw here,maybe the US,but I’d prefer to use a Coach Screw / Lag screw as you can drive them with a socket set,also use a bit of lithium grease on the screw as well as if it binds on entry you’ll have a problem.
There are M10 X 120mm A4 / 316 stainless coach screws available in Dublin from http://www.inox.ie,he charges € 21 for 10 there are also M10 X 130mm ones available in the UK but they’re €6.82 each BIG difference in 10mm,INOX is always cheaper than the UK suppliers.
Again,be very wary of really big screws,I wouldn’t go larger than 3″ in brass as it’s too soft,Silicon bronze would be way better.
There is an easier & cheaper way out of you dilemma,it just requires a bit of lateral thinking,its a system we use joining handrails together.
You just have to be accurate in drilling & measurements,basicallyoffer up your centreboard box to the hullhave your pilot holes pre drilled in the keel Through the hog drill through to the CB box for 2 to 3 inches THEN drill a hole at 90 degrees to the original hole so that you meet the first hole,cut out a neat slot so that you can insert a nut & then you can thread a lenght of threaded bar through & tighten with a nut on the keel side,will give you way better fixing than any screw as you’re not relying on the threads to hold the CB box,then make a little flat plug glue it in and your finished.
Just checked for you on INOX.IE he HAS M8 X 150mm A4 bolts ,part threaded ,which is better & they’re only € 1.80 each plus VAT,WAY cheaper than the UK & local to boot.
Just a word of warning ,marine grade stainless REQUIRES oxygen to maintain itself,if kept in
damp anaerobic conditions it eill lead to disintegration over a period of years,so having the ability to remove & check them every 5 yrs or so would be an advantage.
But the real advantage is a massivll strong fixing.
Hope this helps.
Regards
Eugene Burke , Akita No 85.
Cheers Eugene,
Plenty of food for thought, I like the coach bolts idea, sounds the most straight forward. I will check out INOX.ie also. Not sure about the handrail bolts, used them before and seems like a lot of work, but it is an option.
Thanks again,
Martin
BTW Martin,
I can mail you on a litte diagram of the procedure ,would be probably easier to follow than my written instructions.
Eugene
Eugene, went down to ONIX today and got m8 x 120 a4 stainless, just the job and very reasonable, thanks for that, it’s a great shop for any stainless steel fixings. By the way how are you getting on with Akita, any new photos?
martin
Martin,thats great,he’s a good guy to deal with,glad to be of help.
BTW I actually remembered the site in the US that has the silicone bronze coach screws / lag screws & they have them up to 10 INCHES long !!
Here’s the link http://www.siliconbronze.eu/acatalog/Silicon_Bronze_3_8_Inch_Lag_Bolts.html
I was on to Peter Scallan & he’s ready to post the final pics of Akita,I’ll send them this weekend.
Was working on the inside stripping years of old varnish & paint since the weekend on & off ,I’ve detailed the Caustic Soda method above ,it works a treat.
My sailing club has asked me to enter Akita in the St Patricks Day Parade to represent the Club,Chuffed or Wot !!
Commodore said no soul in a plastic boat & he’s right.
Eugene
That site is in Belgium,the Imperial screw sizes led me to believe it was the US,they will also send VAT free if you are registered
Eugene
“Soda Blasting is kind to the timber, particularly if used wet but expensive and needs careful cleaning afterwards”
Hi Roger,
Just to give you a heads up on my progress in stripping the hull interior.
I spent about two hours removing the thwart & seats & applying the Caustic soda mix to the varnished planking & ribs,it took about 7 hours over 3 days to strip back to barewood,using € 5 worth of caustic & a cup of washing up liquid.
The under decking had blue paint over white, well coated around the centre of the boat.
I mixed half bottle of caustic € 1.75 ,let it lie for 20 hours & I didn’t scrape it this time I brushed it with a wire brush as I didn’t think it would work as well with the paint,
The white only was 70% removed,it took all the blue coat off & about 20% of the whiteunder that,It worked much better than I expected.
I have given a second coat of caustic today & will brush down again tomorrow & see what happens.
The reason I’m just brushing now is that it works better around the roves & am letting the caustic do the work,so far it has cost two bottles of caustic @ € 3.50 each.& about 50 c of Lidls best washing up liquid
Oh yea ,I have forward & aft bulkheads fitted,so internal size reduced.
If your timber darkens with the soda blasting Owatrol NET TROL should bring it back .
Caveat ! I know soda is easier on the timber than shot blasting ,but it could eat into any softness in the wood I have shot blasted teak previously & you’d be surprised how fast it can eat into any slightly compromised wood,just be carefull.
Would be very interested to see a pic of the finished result,I’ll post some pics of the caustic progress
Eugene
Akita ready for re coating inside & should get to it this coming week,will post results.
Co Incidentally ,I heard today that there is a guy in Kilkenny that does Soda Blasting.
Only problem is that he seems to want you to bring the boat to him.
Will check out details & post
Hi Guys, Looks like I’ll have to remove centre casing on Shivona,any tips or advice on the best way of approaching task would be appreciated,Thanks Eugene
Mermaid Sails
Discussion about anything to do with Mermaid Sails (excluding Mainsail reefing).
Last summer made 2 booms from popular/tulip wood in a laminated construction for Sea Fox and Argo, kept within the measurements. Tested them for springing and were surprisingly quite stiffer and stronger and with no weight difference.
Posted by KINEARLY: Guys i had an accident in our workshop, fortunatley we saved almost everthing except our brand new jib, just wondering if anyone has a spare that i could purchase at a reasonable price, cheers Alan 086-2260099
At the AGM on 23rd February there is a proposal to change the mainsail reefing rule to
“(xi) The mainsail may be capable of being reefed to a size no greater than80% of its full size”.
What are your views?
Add your comments by clicking on Reply above right. Ensure that your name and/or boat is identified in your comment. Anonymous and offensive comments will be removed.
The Mermaid sails with almost uncontrollable Lee Helm with a reefed 80% mainsail which why no one ever races with a reefed mainsail no matter how hard it is blowing.
If the rules are altered to allow a smaller reef % then it opens up the door for people to install mini slab reefing sytems which could be used for racing. This would add complexity and cost to the boat and give an advantage to those with deeper pockets and the resources to install such systems.In fact they are probably legal under the current rules anyway.
It makes sense to eliminate the requirement for the mainsail to be capable of being reefed and indeed to ban reeefing for racing or the use of an undersize mainsail.
FYI the current reef moves the mainsail’s centre of effort forward 90mm and lowers it by 260mm. The area reduction is 18.8% from 12.2sqm to 9.9sqm. Total sail area reduction (inc jib) is 13.7%. I suggest that a smaller reef which allows helm balance would not be cost effective since wind speed squares wind loads. So the effective wind range would only be increased by a few knots.
Des
Really interesting observations. In the late 1980′s I bought a North Mainsail which subsequently proved to be a liitle undersize and too flat and to compound its shortcommings it also shrunk quite a bit. Obviously the sail very seldom got used in serious racing anger. During a very windy Championships in 1986 in Clontarf we tore our good mainsail and had to to use this North sail for the Wednesday race. Our speed upwind in the 20Knot plus breeze was unbelievable and we won the race doing handstands. It had no effect on our downwind speed which was probably more to do with pretty good handling (he says modestly) in the tough conditions.
This leads me to think that it might be very worthwhile to cut down an older mainsail by say 9″ along the foot to be used on those 20Knot plus days!!! It would move the centre of effort forward and lower the it by somewhat less than your calculations and provided an easier to sail set up without to much loss of usable power!!! If they do not change the rules to prevent this I might have a go at trying this.
Kieran Foley comments: In view of Des Mc William’s and Roger Bannon’s remarks on undersize or reefed mainsails, is there anything in the rules to prevent using sails which are deliberately made up to be undersize?
Sounds like a potential arms race in the making!!!
Remember the Mermaid anti arms race rules: max one jib every year, spinnaker every two years, one main every three years.
If you buy a ‘small’ main, your regular main could be racing for 6 years!
I dunno, I think it would be a great way of exptending the racing life of older sails if it proved worthwhile. It would be madness to buy a new undersize mainsail unless you were trying to exploit the width measurements to create a roach on the mainsail leech.
Roger, how about looking out an old main and I’ll put in a short reef to try out. I would be interested in finding out what increase in tolerable windspeed results. I’m guessing it’s not worth the candle, but it’d be good to have hard evidence instead of opinions!
AGM approved the change.
National Boat Measurer
It’s that hairy old chestnut again! Weighing of Boats will be discussed at the AGM on February 23rd.
What are your views?
Add your comments by clicking on Reply above right. Ensure that your name and/or boat is identified in your comment. Anonymous and offensive comments will be removed.
I am not sure what’s the issue with weighing boats.Is it about altering the minimum weight?
I have done a lot of weighing with a few boats in different states over the years and when I reviewed my records I thought the following information might be of interest.
For fairness, all boats should be weighed in a dry condition. Hosing down a boat before weighing and sponging out excess water will add 2-5Kgs to the boat weight (depending on water absorption.by ropes, buoyancy covers, and bare timber.
A traditionally built boat coated in normal paints like Endeavour will put on up to 8Kgs after 3 days in the water.
MyDi, which was one the more modern boats coated entirely in epoxy of one type or another (including Eposeal), depending on location, put on less than 2 Kgs after 3 days in the water.
Dolly, The composite boat, put on no weight after being left in the water for a few days.
Are we suggesting that more recently built boats which have been epoxied should carry an additional weight penalty to equalise them with the older traditionally built boats?
Unfortunately the reality is that the epoxy built boats are not only drier but considerably stiffer which generally makes them all quite a bit quicker when the breeze goes over 10Knts.
This might confirm the pattern of older boats only featuring in championships which have experienced generally lighter conditions.Having said that, there are a few older boats which have been very well upgraded to be almost as stiff as the current generation of “epoxy boats” but they will always struggle to compete in heavier conditions.
Should we ban the use of epoxy in boat construction and force the existing epoxy boats to carry a additional weight penalty?
I would not agree with this but is it the logical conclusion that the genuine traditionalists should be considering?
Do you barely know a chisel from a cringle, then this is the discussion thread for you. Post your questions here for experienced Mermaiders to respond.
Do you know the difference between a chisel and a varnish brush?
Major Mermaid Restoration/Rebuild
Three new Rush boats are under construction and ready for planking. Photos available on Picasa: https://picasaweb.google.com/MermaidWeek/NewRushBoats#
There is now a new Forum/Blog for the three new Rush boats under construction. Click on NEW BOATS on the menu at the top of any page on http://www.dublinbaymermaid.org
Kieran Foley, and 
Roger Bannon are discussing. 
ciaracics, 
Alanna141, and 
kinearly are discussing. 
Eugene Burke, 
paddy, and 1 other are discussing. 
martin smallwood, and 2 others are discussing. 
Roger Bannon is discussing. 
Roger Bannon 6:27 pm on February 13, 2011 Permalink |
There seem to be some material omissions from the published rules and specifications known as the “Blue Book”.
Rule 10 At the AGM which finally approved the wooden rudders version 2, the class adopted a “grandfather clause” for wooden rudders fabricated prior to the this latest rules revision. This was to accommodate the early rudders built under the first version of the wooden rudder rules which was very poorly drafted
Rule 11 B (viii) The rules were amended to permit attachment of the lower or main shrouds below the spreader bracket, I think within 2″. Under the old rules it was not possible to fit the main shrouds here if the spreaders were fitted at the minimum permitted height. This is the ideal engineering position for both the spreaders and the main shroud attachment. Many now use customised spreader brackets which incorporate an attachment point for the main shrouds underneath the the retaining plates for the spreaders..
Rule 11 C (e) This rule was amended to make fitting of a sail track optional on the boom. This was because it was now superfluous with a loose footed mainsail and was an unnecessary cost.
Rule 12 B (viii) and 20 (c) Loose footed mainsails are now permitted. The prohibition on a double luffed mainsail however is still valid.
Rule 16 This rule was amended to permit projecting devices to be fitted to the bow for the sole purpose of preventing the spi sheets from falling under the bow.
Rule 20 (h) The use of kevlar or mylar (or other single film fabrics) in mermaid sails was banned during Barry’s time as President in controversial circumstances. The main reasons were anxieties about cost and durability which maybe should be re-examined as the cost differential has reduced considerably. However personally I would not like their visual effect on a mermaid.
Rule 22 This rule was changed to allow paint other than antifouling on the bottom of the boat. This was passed shortly after dry sailing was allowed as most boats did not need to antifoul anymore which is very expensive.
Other things to think about?
Spars
As the rules are currently drafted, spars which are laminated are not permitted. This is more honoured in the breech than observance as it is very difficult to get timber of sufficent size and quality to make up in the maximum permitted 3 scarfs in a mast. Most recent masts made by Duffin Brennan and Peter Dunne would fall foul of this rule.
The strenght of the booms would be greatly enhanced by permitting lamination.
Kicking Strap or Vang
The current methods of fitting a vang in the boat are not very effective and place huge loads on the boom because the of the flat angle of leverage. It also restricts space in the front of the boat. Why not consider permitting the Knav type arrangement you see on many dinghies nowadays similar to that on the LaserSB3? Less boom breakage from reduced loads, more space in the front of the boat, less to break and go wrong!!!
Epoxy Built Boats
Recent boats built in the last 15 years have all employed considerble epoxy in their construction and coatings. These boats are much stiffer and absorb a lot less moisture than traditionally built boats. They are universally faster in stronger breezes, (though that may have more to do with hull shape opitimisation) and tend to remain lighter. This is a very big performance advantage and seriously undermines the “one design” aspiration of the class. Is it time to even up the playing field by penalising these Epoxy boats with extra lead correctors, say 15 Kgs?
Jib Cunningham
Many boats are now fitted with jib cunninghams and some also have stuff luf jibs (supplied by North). Are we happy these comply with the rules? I think the jib cunningham is OK because the rules state that all running rigging is optional but I am not so sure about the stuff luff jibs.
Deck Widths
some boats have been built or redecked with decks which do not comply with the class rules on deck widths. Some have fiited wider decks than permitted to facilitate closer jib sheeting. The aft decks on many boats exploit the fact that there is no measurement point towards the aft cockpit and make them narrower to facilitate greater space for the skipper. I have no problem with the aft deck modification as it complies with the letter of rules, does no effect safety and has no impact on performance. However I think deliberately widening the decks to improve sheeting angles is more than a bit naughty, particularly when it exceeds a designated measurement parameter which impacts on performance.
Kieran Foley 11:15 am on February 16, 2011 Permalink |
COMMENT MOVED BY FORUM MODERATOR TO THE “MAINSAIL REEFING” THREAD
Mermaid Sailor 2:56 pm on February 28, 2011 Permalink |
An draft of the updated Blue Book is now available for Download: http://www.dublinbaymermaid.org/index_files/Downloads.htm. Thanks to Roger.