Having discused over a bottle of wine or two at NORFOLK WEEK and burton week that there is a case for nondouble bottom boats because some of us are not as agile as we were but still like to sail 12s and find scrabbling around in a double bottom boat uncomfortable. I think there are sailors out there that would like a new boat and have no intention of doing champs but would like a modern design.All we need is a builder (not me) so what do we think?
Hi Gerry,
I have wondered whether the following mods. might make for a more easily sailed boat?
Raising the sheer slightly, therefore having the deck higher relative to the double floor (same height difference as AC boats),
Having some kind of side benches, which could also stiffen the boat up,
Lowering the double floor so the boat is only partially self draining, like RS200, or a two height double bottom, like old Hornets or FD's.
The benefits of the double floor are that they stiffen the boat up, you do away with self bailers and you don't have to sail the boat in a way that keeps the water out.
Your boats with the back tanks went some way down this route since you could survive a leg with a fair amount of water in the bottom, it would be interesting to see if a big back tank and a front tank that came back to the shroud base, would make an easier boat to sail, whilst being as stiff as the DB boats. You would still need self bailers though.
Is it the height of the double floor that is the problem or the fact that the new boats are also so beamy?
Regards,
David
N3461
Gerry,
Is there anything in the rules which prevent a boat from having a longer mast, raising the boom to allow easier passage across the boat?
I have a design 8 and with max kicker on get some dodgy moments when the boom crosses the centre line and catcches my B aid.
Lifting the boom seems to me to be a simple answer, and not much lift would be required so may not be difficult to do?
Roger
3334
After having been filled with water after a capsize yesterday in my Tigress, I couldn't get the water out and kept heading into wind. We ended up drifting into shore and walking her around to a suitable point to bale. Disaster is in my opinion programmed into AC boats without enough uplift to get the water out and with a heavy crew. I personally am on the lookout for a reasonably-priced DB Chapter, since in Autumn the gales throw us around too much on the Ammersee.
In answer to Davidg's posting, the bouncer(I think) was once also designed to have tanks all around. It looked like a mens' urinal, but wasn't self-draining. You still required Andersons in the floor. The result was also a bit tight for getting around, but at least you could stretch your legs. Good for all those with dodgy knees.
Another alternative would be to carve out a DB and leave enough bouyancy in the boat, fitting Andersons in the bottom. Seems a bit of a waste, but there you are.
Cheers
Jim N3130 (Don't accept sweeties from a plastic fantastic ;D )
Have some of you been listening to my musings on a customised "geriatric" twelve? I had been thinking of increasing the hull depth on a standard design of hull to give scope for a thwart (essential for geriatric crew) sufficiently high above floor to help crew's knees. Also helping geriatric helm stagger from side to side when tacking or gybing without tripping over the gunwhale when he gets there! Extra windage from high freeboard does not seem to harm Gavin's boat. Boom height would also have to increase at least as much as the extra sheerline height. A plus point would be the raised sheerline would give scope for increased beam forward and aft without severe distortion of hull shape. Downside is extra freeboard can make recovery from capsize more difficult.
Designers please note: if both helm and crew are geriatric then hull must be a weight carrier!
Gerry
I think Gavin Willis has all your answers!
Terry
Very interesting discussion here coz, as many of you know, I have to sell Crazy Diamond because my knees will not cope with the clearance between floor and boom ie deep squats or crawling/falling on the knees.
1. The coven who crew for me say that they will all mutiny if I get a Gavin boat; the Old Dragon has also threatened divorce! :o
2. I can get the water out of the China Doll which only has a bow tank and two rear bouyancy bags but it does take some time; there must be a way to increase the lift without partial double floors (which add weight as well as strength). The bouyancy bags are useful protection when the helm falls over! What about small bags each side of the centreboard case positioned so as not to trip up the crew? More self balers?
3. Dolly Daydream has a high boom end which lifts the cross measurements and makes tacking much easier.
A few answers,
Roger, mast hight isgoverned by a measurment from the sheerline but there is nothing to stop you raising the boom but that means new sails to fit.
As for Jimbo if there is enough wind to capsize there is enough to empty it, unless it is gusty. Sit well back plate at least half up to bearawy onto a reach
David I have built boats with the front tank back to the plate case and same hight, a wide plate case as bouyancy and low stern tank ie a db with a foot well, it worked well
Interesting stuff... I have a wide AC with a double rear tank about 18" deep with an open transom. There is a step of about 5" into the foot well and self bailers. Lots of room under the boom.
I still getting the hang of it and we have been swimming more often than not in the recent gusty weather.
The advice given by Tim would seem to fit the bill and I will try getting further back, rasing the plate and putting the power on. My main problem at present is with rescue crews who think we must have a problem as we sit so low in the water when filled and are really keen to rescue us.
Has anyone tried to build a duct/pipe with a non return valve throught the rear tanks from the floor well to speed up the draining once underway again?
I don't know about 12s, but a chap who works for us has a races leaders and they have 2 four inch waste pipes through the rear tank with a crude rubber flap as a non return valve. Apparently they work quite effectively. (Of course in a 12 they would have to be carbon tudes with mylar flaps ;))
One solution is to put draining tubes through the back tank and then use plastic funnels to seal the holes. A bit of bungee knotted off will keep them under tension. Very low tech stuff - we used to do it back in the 70's and 80's! It worked very well on my Mr Jones
Further to Tim's comments, I would stress the need for the crew to back the jib as soon as both people are in the boat to ensure the wind is gets onto one side - the boat always seems naturally to start off head to wind and in irons. The helm usually has first to unwind the mainsheet from the tiller. Once moving, sit far enough back to stop water coming over the bows or the whole object is defeated.
Regarding the rear tank - a lot of boats built in the eighties had these low rear tanks. I have never really had a problem with them restricting the flow of water. Once the water level is below the tank top the self-bailers do the rest. I certainly would NOT consider fitting tubes through the tank as these would always be a leakage problem. The only advantage I see in bags is that leakage is obvious, i.e. they go flat. The rear tank adds greatly to the stiffness, which is one reason (I suspect) they were popular at the time.
Finally, I have always struggled getting the water out on a river as I always seem to capsize when it is gusty - and then it goes flat calm again.
Philip, N3217 (baggy with tank) & N2545 (doll with bags)
TimL and Gerry,
Thanks for the comforting propaganda. One question. What happens when there is so much water in the boat that it keeps on coming in over the deck towards the transom (model Tigress Bob Hoare, aka Midnight Blues) ? Is there a remedy for this kind of ailment (appart from of coarse either rapid weight loss or jumping out for a whilst the crew does the bailing housework)? I've tried increasing the bouyancy bags at the rear, but that just leaves less room and is something (more) to trip over.
Jim N3130 (give me your...etc and forget the sweeties..)
No that's prefectly normal Jim - what you're trying to achieve is enough acceleration that the boat will suddenly empty i even if water is at first coming across the aft sidedecks. Fitting bigger bags aft actually defeats the object as you want to keep the boat at as steep a 'bow up' attitude as possible.
The key thing is that once you decide to get going you really go for it. It is not gently, gently. Pump the mainsail hard and bear off onto a broad reach. lots of water should go pretty quickly. once you have have got a good quantity out tack round as quickly as possible and burn off in the other direction. after a minute you should be able to start going upwind and use the self bailers to empty.
With elvstrom bailers, the larger 'super-suck' ones are the best to have. I consider the smaller ones a waste of time.
If you have not drained enough you will start taking more water on over the bow. 2 options sit further back or sail offwind again to empty more. In the good old days if it was really wavy helm and crew did not go to far forward after the leeward mark in order to keep the boat dry upwind. i certainly remember crew hiking with a leg behind the thwart.
DB boats are harder as you have no time to sort yourself out. you must start sailing as soon as you are back in the boat or you will flip. that said there is nothing to drain if you get it right.
from 1988 - 1998 i had a lot of practice doing this.....
john
I started this to sound out the less agile of us who find dbs uncomfortable not those who insist on filling their boats with water as they will be better off with a db.
Ok, knock it off both of you.
Discussion forums going off topic is much like death and taxes - absolutely guaranteed so no need to get miffed if the inevitable happens.....
If you want to really assess how many people are interested in single bottom new builds or variations on that theme then maybe picking up the phone to likely suspects is a better bet.
Hi Jimbo,
Gerry is a gentleman and has contributed a huge amount to our class, especially in building competitive boats at a reasonable price at a time when 12's looked like furniture and were priced accordingly.
Both threads are important, Gery has highlighted an issue that may make our boats less attractive to stalwarts and newcomers, it is very easy for us with carbon double floor boats to make decisions based on our own preferences and skills that have been honed over too many years, whilst making the boats too difficult for newcomers or those with crumbly knees.
I watched Josie and a friend sail at Salcombe Town Regatta and am firmly of the opinion that they would have found (ironically) an old Gerry Crusader much easier to sail than my DB, I would go further and say my DB has probably put them off sailing a 12 where a competitive more easily sailed 12 (single bottom) might not.
Jimbos point and the stuff about emptying AC boats is equally valid, but it would have been better to start a separate thread. Also don't forget that it is sometimes faster to empty the boat on a beach than try and self drain in marginal conditions.
Mr Webmaster is there a way that we can archive threads that would be useful references for those seeking advice, such as righting capsizes, setting up dangly poles and emptying ac boats?
Regards,
David
N3461
To Gerry, my apologies. Maybe I read a little TOO much Shakespear into your one-liner. ;)
I remember talking to you at the bar one evening (Wednesday?) at BW on just this subject. There must be someone out there interested in (re) building a single-bottom that is competitive and that suits the needs of those who might, for what ever the reason, prefer a little more leg room.
To davidg, good idea about the thread compilation. Hopefully Josie & Co are not altogether put off by the DB boats.
To the others, thanks for your input. I'll print out and read carefully.
Cheers
Jim N3130
Watching this thread and read with some confusion?!! ??)
Given comments made over the last month about attracting new blood into the class, i am sure we need to make it attractive for ALL people to sail, and it seems that the easier it is for older people, (and I probably would include myself there!) to sail the class, the more people there would be sailing the class from all age ranges.
Knowing how good Bim's (and others) designs are, what is stopping a builder building a Feeling foolish or Big issue in single bottomed format.. Am I missing something, or do the rules prevent that..
Am i barking up the wrong tree??
Martin you are barking up the right tree.
The original Feeling Foolish is 'single' bottomed, although I believe that it is the only one that is, although Bob Murrell has done a retro conversion job on 3435 to make her 'semi single' bottomed. The Big Issue came along after double bottoms and they are all built that way.
The difference is that until 1996 there were loads of buoyancy restrictions that builders/designers faced. These were then removed almost entirely. Thus the 3435 arrangement was not legal pre 1996, but does have more depth, in this case for the crew but not the helm.
The best thing about the 12 is that you can have what you what. The issue is building a lightweight and stiff hull. Double bottomed construction has enabled lighter hulls to be built more stiffly. However I am sure that a full 'draining' boat is not required to get either the light hull or the requisite stiffness.
You also have great options with respect to sail plan as Gavin Willis has demonstrated. The height of the top of the sail is restricted, but the boom can be absolutely anywhere on the mast and the relative size of main and jib and where you put the mast is entirely free. Evidently there are some pretty familiar ratios/measurements that the majority of the fleet go with, but there is great opportunity to ignore these and go your own way as Gavin has demonstrated.
Go on, do it!
How deep are your false floors? A boat will self drain with a suprisingly low false floor - my last Cherub had only a couple of inches depth at the transom. I would think if you went for a double bottom boat with a minimalist false floor there wouldn't be that much difference between that and a single floor boat, especially at the blunt end. The only drawback with a very shallow floor is that you can end up with a boat that doesn't self drain with bow down/heeled light airs trim, but to save the knees that's probably livable with...
How deep are your false floors? A boat will self drain with a suprisingly low false floor - my last Cherub had only a couple of inches depth at the transom. I would think if you went for a double bottom boat with a minimalist false floor there wouldn't be that much difference between that and a single floor boat, especially at the blunt end. The only drawback with a very shallow floor is that you can end up with a boat that doesn't self drain with bow down/heeled light airs trim, but to save the knees that's probably livable with...
Jim,
Most of the double floors are as low as you can get, I think that ours is about 1/2" above transom edge at the centreline. The issue is a lot about the changing geometry of the boats, not only have double floors been introduced, but decks are narrower (as a result of it not mattering if water comes in) and the maximum beam is run to the transom. Also some boats have gone without a thwart.
Meds is right, you could bring the forward tank a lot further aft than the pre-rule change boats and a stern tank and possibly bouyancy around the centreboard case would reduce the volume of water carried around (if it gets in) considerably (Soap Dish is a case in point).
The original Big Issue had a low floor (below DWL?) and a self bailer as does the RS200 and the Laser.
Personally I can live with the double floor, but if I were to have another boat I would look more carefully at the ergonomics, and I am sure I would have slightly higher topsides and probably some kind of side bench. I hate the idea of ever having self bailers again.
David
N3461
False floor height is quite limited by the amount of rocker in the boat too. the rocker you have, the higher the floor effectively has to be to get the water to flow out the back. I think this is one of the reasons the foolish is such a handfull to get upright.
Transom flaps are actually pretty sensible on db's. stop the boat capsizing on reversing, and hold the water in the boat until you are ready to go. I always go for small transom openings to help slow the initial draining process until you underway.
As for a new AC boat, if someone wants one I will build one, but no-one has asked!
I sail, and have frequently capsized the first Big Issue.
As pointed out earlier the double floor is fairly low with a single self bailer at the back, I think the shearline is also a little higher than most, although nothing like Gavins!
Following a capsize with 21 stone in the boat a poot of water about 6" deep sits in the back of the boat, this drains very quickly as soon as you get back on the move. Aside from the drag of a self bailer this seems a pretty good compromise.
Tony
N3428
I think the last few posts of this topic are spot on the important points for consideration and my thoughts are these:
Stiffness depends partly on how the hull is built and what it is built from from. For instance of my two boats 3373 is built to the old rules but even today is considerably stiffer and more bump resistant than 3491. 3373 has kevlar as well as carbon in the lay up which I believe may partially account for this. She also has a floor (single bottom) about an inch thick. Even though she has wooden decks, thwart and centreboard case capping she still carries about 10kg of correctors.
Side decks, in my humble opinion, are generally too narrow today. As well as allowing more water into the boat when roll tacking this makes them less comfortable for sitting out on in a breeze, which in turn makes it harder to sit out for long periods. 3373 is easily the most comfortable N12 I have ever sailed and when we commissioned 3491 Jane & I had Mike copy the decks from 3373. I have to say he did a pretty decent job of that so 3491 is the next most comfortable 12 I have sailed.
Draining water from the boat underway seems to be about the same whether in a single or double bottom. In a breeze it goes out the back or down the bailers at about the same rate. In light weather it sits at the front until the crew weight is moved back or it is bailed by hand as applicable. I do not subscribe to the idea that self bailers add meaningful drag, in fact when they suck air there is a longstanding argument that they reduce drag. The only difference is in a capsize when the self draining attributes of a double bottom mean that it empties far quicker. However, as plenty of people have pointed out, this can be a problem if the water goes out too quickly (i.e. before the crew is back in the boat, has everything untangled and is sailing again) since the boat can become unstable and assume the horizontal position again.
At the end of the day if the rig is kept above the hull, the underwater shape is right and the boat is well sailed it will win regardless of buoyancy arrangements. I think semi-self draining (like the original Big Issue or RS200) is right and have said so for a long time. (Could this be a significant factor in why the RS200 has outsold the 12 recently? Oops, that's another topic).
Kevin
N3491 - for sale
I am coming up to the 1 year aniversary of owning my AC 12 (baggy). Sailing it since March - I've had plenty of opportunty to right it from a capsize.
I have found that in certain conditions It really is difficult to get the full boat out of irons. I had one really miserable experience a month or so ago when i capsized on the first tack after my best ever start! I was still in irons when the lead boat came round the start line again!! (I would like to think that my slim centreboard section also makes the boat more prone to stalling in the tack, whch could make this problem worse as well)
The advice I did get from the northern hoard was to a) keep the boat as flat as possible once righted, not heel at all and b) sheet in the jib only to get going, only sheeting the main when you have started to move.
I have not capsized since then so have not had the chance to put these tips into practice, but they sound like the missing information - cos I thought I was doing everything else that had been advised at the time.
Philip
N3253
That should sort your problem Philip. You may need to back the jib a bit at fist to get to bear away enough then sheet it in on the other side and let it steer you onto your course. sheeting in the main will tend to turn you into the wind so must be left until you have adequate steerage way. Have you tried sailing with no rudder yet? It's well worth it as it teaches you a lot about handling the boat (not recommended for racing though!)
Back to the original issue - I''m sure there could be a market for " in beteweenies" on the floor height. This would help with the righting problems and add to the comfort factor - particularly I think for those in the front. Fortunately my knees haven't complained too much about the double bottom but I'm not sure that my physio thinks my light weather sailing postion is particularly beneficial to my back!
There is of course no reason why someone shouldn't commission a lower floored or new single bottomed boat - the latter may well be cheaper to build too? Apart from the questionable aesthetics Gavin's boat certainly fits the bill for Gerry - there must be a halfway house solution too on the sheerline height which could produce a boat kinder on the eye but with a bit more knee room - should we look forward to seeing you in a new boat Gerry!
It could give someone more confidence on taking the single bottom route if they new that others might follow - or that there would be a demand later on the second hand market at similar prices to those of double bottomed boasts - views?
Cheers
David
3841
Actually, thinking about it, what does make you feel the need to kneel in a double bottom boat... No arguing with the phenomenum, but I don't find myself doing it if I jump in a Topper or a Laser, and they have little false floors and very low rise to the side decks... Do you think its as much to do with the width of the decks as anything else? Oris it maybe a feel thing with centre of gravity? Has anyone sailed a 59er? Supposedly Bethwaite designed that with the mature sailor in mind, but it is false floor... Do you end up kneeling when you sail that?
David,
I thought that Derek was going for the latest sail no with 3510..................... do you know something the rest of us don't?
And as to a 'new' AC boat, the egg has been laid, just not sure how long it will take to hatch!, depends on knee ops and the like ( Sorry Paul T you and I have something in common - Wild Oats?)
Not certain who is" laying the egg" but I have now built up a specification from this discussion group, and from personal experience, of a design for those of us who are over 42, slightly on the heavy side, have knee problems, don't necessarily have the same crew every week and want a simple to sail easy to maintain N12 yot at a reasonably cheap price - not hi-tech but reasonably competative.
What a dream! ;D
"reasonably cheap price - not high tech but reasonably competitive"
This is probably the hardest part of the spec. The difference in the cost of a low tech boat versus a high tech boat is going to be the difference in the cost of materials, the labour costs are likely to be the same. To compromise on the rig or foils will probably save you say 15% of the total price, but will still be more than a good high tech boat with all the toys.
The only way really to get the costs down is to get sufficient interest that allows a series of hulls to be produced, probably where you have direct access to the buider.
I think that this thread has identified some of the improvements which might make for a more comfortable and ergonomically better 12. It should also be possible to produce a stiff boat which has some of the benefits of a self draining hull. On a wavy Burton Week course the single floor boat is still likely to be better, but since Burton Week is about the only decent sea venue that we have left, this should not be considered as the be all for development for most of the class.
Kevin has reminded me of the possibilities of a thick sandwich construction in lieu of a double floor, this would also make for a stiff boat.
Interesting stuff.
David
3461
Perhaps what is needed here is for a builder such as Winder to offer a single bottom option. They have developed a very stiff Merlin along this theme so I would think a 12 could be easily adapted. The problem of going it alone is one of investment and the risk you run of spending a lot of money on a boat that maybe you would find hard to sell, if it has the backing and name of a builder like Winder then you mitigate this I think. I know of some crews (mine included) who refuse to sail a double bottomed boat a problem that probably was not considerd at the time the decision was made to go that route. I watch this will great interst as I'd like to take up regular 12 sailing when the kids move on from Cadets in a few years time.
David I have tried Winder they aren't interested at the moment and the moulds may be for sale.Perhaps we should speek to P&B
I have been off line for a while due to holidays and come back to a host of interesting things being discussed. To barge in on one of the points made regarding AC boats and emptying. I do not believe there is a maximum number of self bailers that can be put into a boat. My old ACer which rarely sees the light of day has four Super Suck bailers, two just behind the bow tank and two more in the usual place just under the thwart and no transom flaps due to stern tank. I have not had too many problems getting rid of water when inadvertently going for a swim either on open water or on a river. As has been mentioned previously, getting the water below the level of the plate case is the key.