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Original Subject Posting
| And Finally Question 6 Floor Stiffening | Date
Posted: 05 Oct 09 21:16 |
| Many old wood hulls if not all suffer from the floors cracking or going soft particularly in the areas where the the crew and helm 'work'. The answer to this has been to 'stress' in a maximum sized floor batten 50x25mm along the floor. This not easy to fit and in the end produces a water trap, something to trip over, and makes it more difficult to rub down the floor when it comes to maintenance time. The answer of course is to epoxy glue a layer of 3 or 4mm ply to the floor runniing from the transom to the front bulkhead and width ways from the hog to the line the sidetanks take on a MKIV. If one was converting to a MKIV this gives you a easy ledge to but your bulkheads and tanksides up to and will produce a strong joint where the tanksides join the floor. I discussed this possibility with a few people at the nationals and one view that came back was that it would be unfair because it wouldn't be possible to fit this floor to existing MKI, II,IIIs. Well I've bitten the bullet and fitted such a floor stiffening to my MKII which to be honest without it would have gone on the bonfire. This boat will have no front bulkhead and side bags as it was when built. I realise that technically my boat may be out of class, although I would classify what I've done as an essential repair. I think people will conclude it is a good idea once they see the end result. For those who say this is weight concentration I would point out that the weight of two bits of lightweight 4mm marine ply and some epoxy is far less than the potential 4 full length solid wood 50x25 floor battens that could currently be fitted to wooden hulls. The volume of wood used is actually less too. Finally this is a relatively easy retro-fit to all wood versions and could save many wood hulls as well as extending the life of existing ones. Tony Thresher |
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| Author: Tony Thresher | Message ID: 166 |
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Replies to this subject
| And Finally Question 6 Floor Stiffening | Date
Posted: 05 Oct 09 22:13 |
| I've never seen a floor stiffener to full depth - is it possible to bend it in? Many old Fireflies have had plywood laid on the floor, usually over rotten wood, in place of doing a repair, so I only have experience of ripping them out and disparing of what I've found. If the boat was going on the bonfire otherwise due to the propensity for feet to go through the bottom, would the ply count as a repair? Plenty have had glass bunged in the bottom for the same reason. And rotted, of course! |
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| Author: Rupert Whelan | Reply ID: 415 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 06 Oct 09 07:56 |
| I may have exagerated a little to say 3173 would have gone on the bonfire. The 'repair' just makes it a whole lot easier to deal with the weak areas of the floor and eliminates the need to torsion in a big floor batten. I hasten to add the hull is back to bare wood inside and out so all potential problem areas have been exposed. I will change the photo on boat register page to a current one this evening. Tony Thresher |
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| Author: Tony Thresher | Reply ID: 417 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 06 Oct 09 20:28 |
| Dont think I can change the photo on the register? If possible please tell me how. Tony Thresher |
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| Author: Tony Thresher | Reply ID: 420 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 13 Oct 09 15:19 |
| click on Peppita's transom flaps on the boat register picture, the updated picture appears. | |
| Author: Chris Guy | Reply ID: 427 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 13 Oct 09 15:22 |
| Looks very interesting It should stiffen the floor nicely, preventing the paint on the outsite cracking and also stop cracks appearing where the tanks join the floor. Mine has a hairline crack where the tanks join a slightly rotten patch. Elements of this approach would have prevented that I don't see why we should not allow this by modifying the stringers rule(i.e. for all marks), I don't think it would make the boat faster at all. I would expect the overall hull flex to be set by the tanks, decks and thwart rather than the thickness inside bit of the floor Essentially this is a repair or it makes repairs easier, so I don't think it compromises the one design nature any more than any of the existing options. We are very pedantic about keeping the hull shape, the foils and the rig the same on all marks. Variation in fitting out and some internal woodwork points have always been allowed i'm interested to hear opposing views though |
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| Author: Chris Guy | Reply ID: 428 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 26 Oct 09 13:55 |
| just looked at the pic - that actually looks very sensible. realistically if i did that to my boat would it be a problem for measurement come next summer? | |
| Author: Matt Findlay | Reply ID: 441 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 26 Oct 09 17:19 |
| Hi Matt, It might be a bit risky to implement this in anticipation of any rule changes. If the rule change was put forward it takes a while to go through. It first has be voted for at an AGM, then put forward to the RYA technical committee to agree to the rule change. I believe the technical committee sit a couple of times a year and they do not work at pace!! This is assuming the class vote on a rule change. As we are only discussing it as a theory at the moment. Any rule changes are a very long way of. If I were you I would make sure the stiffeners are a big as you can get them. Make sure side tanks very well secured to the hull. With big fillets inside the tank. Any bulkheads also very well secured with big fillets. I re-did my side tanks and they are not going anywhere! As a result the floor is very stiff. Speak to an epoxy expert for advice on filler ratios to make the ideal fillet. Dace Chisholm is a good place to start! Cheers Will |
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| Author: Will Mason | Reply ID: 443 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 26 Oct 09 17:27 |
| I would be cautious about doing the whole floor, but talk to a measurer about perhaps butting up one of the stringers to the tanks. they can be up to 50mm wide and that I think you could do under the current rules If you did the whole floor ir would be difficult to undo and remember this is a rule modification that could be voted down at the AGM We voted against even trialling a new sail cloth this year! Of course with lots of your mates as full members at the agm anything is possible... |
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| Author: Chris Guy | Reply ID: 444 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 26 Oct 09 19:45 |
| Matt, As Will and Guy say what I've done is marginal as far as the current rules go. If a rule change is required then technically stiffening the floor in this way would take until March 2011 to become legal even if our AGM passed the change in 2010 and assuming the RYA ratified it. The question is whether what I've done can be classed as a legitimate 'repair'. Given that their were a number of holes and other rotten veneers in the floor of Peppitta I would maintain what I've done is a structural sound and cost effective way of repairing the floor and something that will prevent problems in the future. The rules say wood hulls shall be constructed of wood laminations using waterproof glue. Epoxying ply to the floor I believe complies however what I've done is not part of the original construction and I'm not a licensed Firefly builder. Equally, gluing max. sized floor battens to the floor are not part of any original construction I've seen but is allowed in the rules. I intend to pass my 'repair' past a couple of measurers to see what their view is. The good news is that it would be a relatively easy retro. fit however you end up renovating your Freddie. Personally I wouldn't go for one large/thick batten as it will be hard to fit and may create a hard spot on the hull. Perhaps better to go for two max. width battens up to 12mm thick and tapered along the edges and at the ends. If you are prepared to paint the floor they can be constructed out of good quality marine ply. Feel free to pay me a visit if you are in the Oxford area. Are you doing a MKIV conversion or just renovating an existing MK? Tony Thresher |
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| Author: Tony Thresher | Reply ID: 446 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 16 Mar 10 17:59 |
| Hello, I am sorry, I am coming rather late into this discussion. Do you have any images of your floor stiffening? Do you apply the stiffening in strips or in one sheet per side? And finally, how do you press the stiffening sheets down onto the floor (with battens wedged between the floor and posts clamped across the sidedecks?) Gotthelf (2957) |
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| Author: Gotthelf Wiedermann | Reply ID: 691 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 16 Mar 10 20:21 |
| Hi Gotthelf Tony's 'experiment' can be seen here If you click on the picture of Peppita a shot of the floor laminates comes up http://www.fireflysailing.org.uk/register/boat_info.php?sail_no=3173 Bear in mind that this was just an experiment and will be voted on at the AGM as an optional type of floor 'stringer' PS It would be nice to hear more views on this as an option for older wooden boats, so that the class can make an informed decision at the AGM We also haven't decided whether to open up the new rules to a 'postal vote' for all those that can't attend the AGM in Tenby. We would put a ballot paper in the summer bulletin magazine. Let us know what you think |
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| Author: Chris Guy | Reply ID: 692 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 22 Mar 10 14:55 |
| Thank you for your reply. I have done some calculations regarding comparative weights, ply panels versus four battens at max. dimensions allowed, assuming a specific gravity of 0.5 gr/cubic cm, which is close enough to pine, ash or similar, as well as marine ply for small boat construction. Calculations assume panels/battens of 250 cm legnth and panels as fitted by Tony Thresher. 4 battens: 6.25 kg 2 ply panels of 4 mm: 3.8 kg 2 ply panels of 3 mm: 2.85 kg (which I would prefer as sufficiently strong, lighter and easier to fit) I think this refit is an excellent idea as it will give a lot of old, tired Fireflies another lease of life. Gotthelf |
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| Author: Gotthelf Wiedermann | Reply ID: 702 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 22 Mar 10 18:15 |
| Chris, yes please to the postal vote, as many of the people who do up old Fireflies are not Nationals goers. |
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| Author: Rupert Whelan | Reply ID: 703 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 28 Jun 10 22:35 |
| Hi Tony, do you offer a Mark 4 decking service? If I am correct, please could you give me an idea of what it costs to deck a boat that has already been undecked? Alternativly, I was looking at trying to track down a deck kit for another proffesional boat builder to complete. any advice would be appreciated. Regards Andy Reilly bdn@3ds.com Tel 0777 1635732 |
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| Author: Andy Reilly | Reply ID: 827 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 19 Jul 10 18:45 |
| Perhaps I am not a forward thinker and scared of change. But as the AGM is not supposed to be the discussion arena for the rule changes and this is. Here I go… I personally disagree with the proposed rule change to allow the batons/stiffeners to be replaced by a new floor. I don’t have any huge technical arguments for not to do allow except for the unknown. We can not be 100% sure that it will not be an advantage/disadvantage. If found or believed in anyway to be an advantage of any sort it will be the latest thing to have. It might not start an arms race but we all know enough people who will make the change. Will Rondar/Porter Firefly’s have the option to do add this feature? How cost effective and practical is it to implement? I think it is will be only possible to do economically with a complete rebuild. To implement I have heard discussions of vacuum bagging which is not available to most Firefly owners. I also have a slight issue with how this rule change is going through. With the MK4 we applied to RYA for dispensation to build a “wooden” Rondar. Ray Smith built Fourwood Thinking and she was sailed for a season at least and proven to be equal, before the class voted to allow the MK4 as a deck design. The RYA then allowed the rule change to go though. A need was identified and the class solved the need and proved it was a viable and feasible option. I am unconvinced of the need to change the rule. This proposed rule change has been implemented on one boat and I am unaware of any trials etc. How feasible is it to implement? Does it give any advantage/disadvantage in different conditions? Now we are voting on it. Not even voting to perhaps have a trail and feasibility study period. No one can be sure 100% that it will not be an advantage. As we do not know for that reason I will be voting no. If i am the only person voting against this rule change then i will shut up! |
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| Author: Will Mason | Reply ID: 853 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 19 Jul 10 21:25 |
| Will, You make some valid points about testing. In this case we are not talking about a massive change like the Rondar firefly or wood Mk4s and I do not believe there is any reason to embark on a testing programme. My experience tells me this would be a sound change and one that would make renovating an old wood boat easier for amateur enthusiasts. Further it will allow the 'flush' floor configuration in the Rondar to be replicated in wood boats (surely only fair). It is absolutely not necessary to use vacuum bagging to retro fit such a floor. Plastic staples are ideal but failing that ordinary staples which can be removed once glue has cured are just fine. As stated before I believe this to be a relatively easy retro fit to any wood MK either by the handy owner or professionally. I have been fitting such floors to Solos for many years both as a retro fit and in new builds. For information the cost of materials is generally between £50 and £60 and I do retro fits on average for about £250. I cant see a Firefly being any different. The question as to whether such a floor could be fitted to a Rondar or Porter hull is interesting if some what of a red herring. I wouldn't have any objection as I have always believed that what is allowed in a build with a particular material should be allowed in another. However I think you will find that the firefly rules are quite specific regarding what is allowed with wood and have left grp moulders and the RYA to produce a product that cannot be modified. Composite boats have basically been finished so they comply with wood rules and there would be no reason not to allow a wood internal skin on the floor which could potentially produce a wood look alike MK4 on a GRP hull. Personally, although I instigated the initial proposal it doesn't particularly bother me which way the class votes. I will vote for because I am comletely confident that it is a good proposal for all the reasons alredy discussed on this forum. Tony Thresher |
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| Author: Tony Thresher | Reply ID: 855 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 21 Jul 10 07:57 |
| Hi Tony, Thank you for clearing up about how can be done relatively easy. My concern is that we do not know if will be an advantage or not. If is seen or believed to be an advantage then we will have lots of people making the modification. Which is not the intension of the rule change. As far as I am concerned the rule change is pretty major as the hull design/construction has not changed in over 60 years except with the GRP boats. As I see it we are discussing altering the hull construction with out any proof that it is not an advantage. As we are not 100% sure it is not an advantage is why I am against the proposed rule change. Thanks Will |
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| Author: Will Mason | Reply ID: 856 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 21 Jul 10 14:11 |
| As we know know the vote will only be open to those at the AGM, it is very important that views are aired here first. If for a moment we ignore whether putting a new floor in a sound boat will give an advantage, lets look at what will happen for a Fairey boat which has seen much use and has started suffing glue failure in the area helm and crew jump up and down on. I'm pretty sure there are hundreds of boats out there where this is a potential problem, and many where it is already happening. There are 3 choices what to do here. Firstly, think, oh, god, the boat is dead, and burn it. Second, pull the hull apart and replace all the failing wood. Time consuming for those with the skills, expensive and time consuming for those without. Thirdly, mend as best in situ, and then stiffen the whole lot up with extra wood. I can see this method appealing to many people, as it gives an old boat a new lease of life without costing the earth, which is what Firefly sailing is about for many people. We then get back to Will's problem - will it make the boat faster than one where the floor is still sound, and therefore not flexing already with every wave or footstep? Personally, I doubt it, but if more time was needed to find out, would it be possible to give dispensation to say 5 or 6 boats who plan on doing it, and see how both their results and construction pan out over the season, for a roll out next AGM if all goes well? I don't think the results from 1 boat would tell us anything at all. |
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| Author: Rupert Whelan | Reply ID: 858 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 23 Jul 10 13:04 |
| i guess it takes someone to make the statement of they might react to this.... I've already done the mk4 already.. However - i spotted this proposal before the job was finished so have left the floor in it's original state (just one battern on each side) pending the outcome of this discussion. If this doesn't get in - i'll be adding a further battern to each sideand a rear toestrap bar. Should this become within the rules, i reckon i'll be lookling closely at taking out the current batterns and reinforcing the whole floor. This is what happened in the Solo's. There's a massive gain in stiffness to be had, a nice smooth floor to get the water to the bailers and it'll look very pretty! (without any stripping!) There will be a couple of issues; - Self bailers - will need cutouts in the second layer as they are not really designed to fit through "8mm" of floor.. - Weight - but i think i have enough to play with.. The other side to this - would be if i were mk4ing after it became within the rules... - do i build my tanks down on top of it, - or nest up to it? - and if i'm doing the case, Do i build my hog on top of it - or butt up next to it? and then how does it affect other measurement points - height of case, etc? Cheers Jono |
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| Author: J P | Reply ID: 866 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 23 Jul 10 15:39 |
| Rupert, Any vote at AGM is open to all members. You can submit a postal vote if not a Tenby. Cheers Will |
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| Author: Will Mason | Reply ID: 867 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 23 Jul 10 17:20 |
| Jono, If you where MK4ing from scratch with the new rule I would butt tank sides up to the edge of extra floor panel. Stronger joint plus it makes fitting easier. One of my original thoughts when applying this to the Solo and struck me it would be relatively easy to supply templates for the floor panels to make home MK4ing easier. Cut outs for bailers means you can produce a small well for them. I'm not sure what your thinking is with the hog and how this effects fitting a new case? The new 3 or 4mm panels will be butted up to the hog edge not over the top of it. Clearly if someone decides to strip the case out, plane the hog down and fit the new style floor over the top of the hog we or rather they have a problem. I'm pretty sure the tolerances would be ok as the amount needed to be shaved off the hog will be within a mil or two of what would be put back on with the floor. However the intension in the wording is that the floor may be stiffened by fitting a 3 or 4mm panel on the floor area defined by the MK4 tank sides and front bulkheads, transom and hog sides. Implies you cant cover the hog. Tony |
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| Author: Tony Thresher | Reply ID: 868 |
| And Finally Question 6 Floor Stiffening | Date
Posted: 30 Jul 10 13:44 |
| Coming into this debate late but does anyone actually have 2 stiffeners on both the port and starboard side in their boat as the rule allows ? I have only ever sailed and seen boats with one stiffener either side. If anyone has 2 each side does it solve the problem of a soft floor in the working areas as discussed initially? We may be making more work for everyone by proposing this new rule of a sheet of plywood either side instead of the battens to resolve soft floor issues. Maybe people just need to put in an extra batten each side like Jono is proposing to do which is currently within the rules. |
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| Author: Paul Kameen | Reply ID: 884 |
