Allow me to show a few photos of my most recent design, SiREN. I will be sailing this at the Wood Lake Footy Regatta assuming initial pond trials go according to plan.
The hull is a development of the Kittiwake but incorporates many detail changes which hopefully will all add up to make a faster boat while staying with the basic two chine design. Trials of a mock up of this hull went very well during the autumn winds here so I am fairly confident.
The SiREN introduces the ‘loose topped carbon forestay’. The initial idea for this came from Angus’ ‘stayed carbon forestay’ thoughts last year. The SiREN forestay is free of the mast at the head and very simply attached to the jib boom. Only gentle tension is required on the sail luff to keep the jib pivot standing straight, a swivel is used to help to stiffen that component. The result is very little tension on the carbon mast and no need for a backstay. A jib topping lift has yet to be added to control jib twist.
Thank you TomoHawk… the sail luff tension keeps the corbon rod ‘forestay’ (it isn’t actually a forestay in this case I suppose) up in position via the jib boom. This takes much less tension than that required to keep a thread forestay taught.
Thanks Barrett… I hope she sails as good as she looks
Graham,
Looks very nicely thought out & executed!!
Please remind me, is the purpose of the carbon forestay intended to limit the jib luff sag, due to lack of backstay?
I’m looking forward to sailing with you on the 20th. I put may sail numbers on yesterday.
If you glued the rod into the jib tack, it would probably keep it from falling out. I had the idea of using a bicycle spoke instead of the rod. straightening the bend out of the nib end will give you a nib that won’t fall out.
Yes Bill, I prefer to use no backstay on the footy but even a carbon tube mast will curve forwards under the tension required to keep a traditional thread forestay taught. A wire with a tread top link will work but still requires more tension that the loose topped carbon forestay.
When I work out a pillar style jib swivel (almost there) I will be able to do away with the luff tension too and glue the jib onto the forestay as TomoHawk suggested. Currently the luff tension is only required to keep the jib swivel standing.
The photo below shows the first test rig with the loose topped carbon forestay (LTCF?). The boat is being hand held in a very strong wind and so the force is greater than any which would occur during normal sailing. In fact the boat was held upright and this gust twisted it to the angle you see, I was holding the keel and attempting to keep it upright!
The black line drawn gives a reference against which to view the forestay curve. This is using a 1.6mm carbon rod.
On sunday morning at Wood Lake we had some diabolical wind effects! It was blowing pretty strong from the south, this is our worst direction as the wind comes over the buildings and the rollers and downblasts are nasty:scared: You can be beating along in fine style when a downblast ruffles the water and lays your footy flat! Up she bobs and you are becalmed, the downdraft having blasted all wind away.
We did have three footys on the water all the same, two Kittiwakes and the SiREN. All three came off the water bone dry after an awful battering! In between the nasty stuff though I was able to learn something about the new boat, and see a problem. I was getting too much friction on the jib sheet so that is was not moving out properly. A long hard look on the bench has found the culprit so I am looking forward to further trials tuesday evening if the thunder stays away. On the plus side SiREN was beating a nice straight track, hands off and is clearly a strong watertight boat. More later… photos next time I hope.
A beautiful Sunday morning sail boosted our Footy Fun yesterday… now I have some photos of SiREN afloat. The friction problem is cured thankfully and she was sailing well… looking forward to some serious racing
SiREN did sail very well on the big day. In pretty tough conditions she was fast and stayed dry. I am of course pleased to see that the development applied to the Kittiwake hull is taking it in the right direction to become a competitive fleet racing yacht. SiREN will I hope make a good partner to the established Kittiwake, production work is starting.
Dare I say that the flat bottomed boat is far from dead :devil3: . My general observations so far are that bulb weight ratio is an important issue. The SiREN you see here is built as per my kit production methods and so is not a ‘special’, the 40.8% bulb ratio should be easily repeatable. A lightweight ‘racing’ hull with balsa skinning will improve that further for those who want to go that route… and I think you should.
The higher than average bulb ratio allowed me to carry the biggest sails I have used to date on a Footy. In the conditions this did take some skill to control especially on the run but careful control of the vang proved very effective. In light to moderate winds I will go bigger yet. It’s hard to beat a bigger engine for speed on the beat and reach.
The stiff carbon loose topped forestay is I think a significant development and worth adapting to any bermuda rigged boat. Just a part of many detail changes which will lead to greater boat speed and easier handling. Here’s to the next race!
I think that Graham has latched onto many of the things that make Footys go, and that this has been borne out in SiREN’s performance. As he says, ballast ratio ratio is vital; the old fashioned-Footy with Beams and Girders of Balsa tying together Ranks of Bulkheads, all held up by a teeny-weeny bulb, is becoming a a thing of the past. Similarly, a vanilla mast was a 6 mm birch dowel onmly a kear ago.Now it is probably a 5 mm carbon tube. Brett’s rigs are using 3 mm carbon tubes and I am experimenting on the bench with 3 mm masts tapering to 2 mm. All of this adds up to a lot of rightinng moment, which is not not far off the same thing as power/eight ratio. SiRREN’s asdvanced forestay system is probably not theoretically perfect, but it is a highly practical solution to the problem of reducing weight and windage aloft within a format of a conventional rig.
Similarly, SiREN’s fuller profile with a deep forefoot and higher prismatic coefficient has to be at least part of the way to go. Footys (or at any rate good ones) operate at very high speed lenggh ratios and need immerswd volume in the ends, even if you do not go to the extent of the VHPB.
Well done Graham, and we’ll meet on the water some time to slag it out.
Much sailing of the Siren has shown that the central fairlead over the cockpit will take in a little water in rough conditions. My Kittiwakes with the rear deck fairlead have always stayed bone dry, so something had to change. Especially with the spectre of salt water at Slithey Tove.
The central fairlead has been replaced by a wire loop guide in the same position on the cockpit bridge. I have then moved the fairlead back to the rear deck which seems to me to be the best of both worlds.
The loop is a good replacement for the more complicated ‘bridle and loop’ as seen on the Kittiwake but the bridge does make the taping of the cockpit a lttle more involved. Having said that only the rear patch need be removed for charging, de-misting etc. so maybe that is not such a disadvantage in use.
I hope the photo shows these changes clearly… The colour overlays are pink-mainsheet, green-jib sheet. The mainsheet passes through all 3 holes of the bowsie, the jib sheet is tied off at the forward hole. This gives quite easy adjustment of the slot.
Graham, I look forward to getting a close look at Siren when you come down to Ormond Beach in october. We will probably be sailing/racing Footy’s at the pond on sunday October 7th. Will you be down here by then. Paul
Hello Paul… yes we should be, we are booked in at the hotel from Saturday 6th. Not certain if SiREN will be coming back with me at this stage, depends if I find too many goodies and outgrow my two check-in bag/box allotment! I will have some sort of footy along though, never travel without one!
Well the mast and sails are too big for the box I was planning on using so on to plan B. That is… put it in my case or cases. I have built a block of EPP foam around the fin/rudder in the hope of protecting the rudder in particular. This block will then fit among my socks and unmentionables for further cushioning. It is my hope that should security care to take a look it will be much easier for them to open my case than a taped up cardboard box. No batteries and no transmitter/Rx so I am hoping for an easy passage.
In deference to Angus’s dire warnings of wind off the Irish Sea I have made a ‘B’ rig. I cannot bring myself to take a photo of it and I hope dearly that it stays in it’s packaging… looks awful! If Footys looked like that we could not sell them to anyone :scared:
Back to the rigging change… Sunday was windy here, at least as much wind as our May regatta so it was a good test. After 3 hours of pretty hard sailing and some deliberate running in the strong gusts she came off the lake bone dry. Success I think. Interesting thing was Toby has been practicing a lot with his Kittiwake and in the stronger winds I could barely get away from him. He had to detune less than me in the conditions so they were suiting him well. Looks like we have competition for next time Bill K! And I guess that bears out Angus’ warnings… oh dear.
