UK-Cherub Forum
Cherub Chat => Introduction to Cherubs => Topic started by: Nick in Bristol on September 03, 2011, 02:53:55 PM
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Afternoon all,
Just bought my first Cherub (2654) and currently stripping back the slightly messy paintjob, overhauling the foils and replacing a few bits and bobs. Going to use it to teach the Mrs to sail and then hopefully doing some very amateur racing in between ear bashings about it being too wet / too cold :)
My sailing background is mostly Scorpions, Fireball's and 505's, so the Cherub will be completely new to me but looking forward to the challenge.
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Fantastic - a trifle in Bristol.
Nick I 've emailed you my phone number/contacts. If you need anything please shout.
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forgot to add -
KEVLAR ALERT
Be careful about sanding. The kevlar will respond to being hit by sandpaper sand by forming furring into a "teddy bear" skin, more sanding makes it worse....
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Cheers for the contact details, I'll reply direct soon - I'm in and out a lot today, one of the perils of self-employment is always being on call. But it does mean I get to work on the boat during the quiet spells :)
Thanks for the kevlar tip too, I've been careful with the sanding so far! More tips most welcome. Fortunately (?!) the red paint job is very thick so easy to see the depth I am sanding to. I'm not taking it back to being bare, just to take out the thick brush strokes and even it out prior to repainting a slightly more tasteful white decking and blue hull.
I've had to fill a few dings, especially a 4cm chunk out of the spinnaker chute lip, but overall it looks pretty sound, just a bit rough around the edges.
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More South West Cherubs! Fantastic! I'm off for my maiden voyage at Chew today. ;D
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Looks a nice day for it too :)
Chew is one of the places that I'm considering sailing mine at in the longer term. In the short term, is it possible to just turn up and sail on the lake without being a club member? Obviously not using club facilities as that wouldn't be right but just a public launch site.
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We are a member at Chew and yes we can happily arrange to be there to sign you in as a guest when launch date approaches. Chew is a reservoir, so club access only. Report from last week is that currently the level/weed make sailing a cherub there a bit more of a challenge than normal and so we are currently using Thornbury (excellent club, steady wind, mild tide issue). We would strongly recommend trying the Chew winter series as a great way to try the club (this usually includes a parking space, Sunday racing and Saturday for "training").
Hayley and I had a storming session at Thornbury today - we had a "one capsize and home" rule in place as I'm currently working all hours and a bit tired / grumpy. Those who know us will be surprised to hear that with a force 3+ we were out for a long sail. Came back grinning form ear to ear after binning a gybe in a race (yes we took Born Slippy out).
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Hi Nick,
I also live near Bristol and sail at Thornbury. Hopefully by the time your ready for a maiden voyage chew will have a bit more water. Otherwise Thornbury is worth considering when the forcast is light to medium as the wind can pick up.
Again as Born Slippy if you need any tips or want to get together for some more complicated bits give us a shout.
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Fortunately (?!) the red paint job is very thick so easy to see the depth I am sanding to. I'm not taking it back to being bare, just to take out the thick brush strokes and even it out prior to repainting a slightly more tasteful white decking and blue hull.
Trifle's aren't exactly renowned for their tasteful paint jobs! The tiger/finding nemo effect was a personal favourite... I suppose it set something of a precedent for us. The (now Holland-based) Flying Trifle was our first cherub and we have very fond memories of her. Also some 'non-memories' - moments of alien abduction where you would find yourself in the water and not know how you got there!
Sailing at Thornbury yesterday was great. I always wonder when we sail Born Slippy in a breeze why we ever sail anything else, but then the E5 seduces us back. It's a good job we had a good sail though, the trip home courtesy of the RAC van could have been really depressing otherwise. Dead turbo :(
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I'm going to have to rethink the paintjob if tasteful is a social faux pas in Cherub circles :) Maybe it's time to use the tin of tartan paint that I waited so long for at the stores as a sprog. . .
Thornbury SC is only a 20odd minute drive away from home as I'm up in north Bristol, but isn't the sailing say quite short there due to the tides? Reading the thread about the Sheppey round the island race reminded me how easy I had it learning to sail as that was my home club for several years. Moving to Burghfield after wasn't exactly a hardship either.
One technical ish question: what dimension rudder blades are people using? The one currently on the boat seems, well a trifle short at about 30inches (76cm).
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One technical ish question: what dimension rudder blades are people using? The one currently on the boat seems, well a trifle short at about 30inches (76cm).
Sounds about right, we sail Born Slippy with about a foot in the water. What is the chord and approximate thickness?
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The size of rudder depends partly on the shape of the hull and partly on your sailing ability.
The overal length of our rudder is 95cm with probably 50-60cm in the water. Cords range from 23cm at the large end to 17cm at the very skinny end. The narrow cord rudders can be longer than the dimension i gave above. A rudder without a t foil will need a little more area than a rudder with a foil.
The rudder on our old boat which didn't have a foil was about 95cm long with a cord of 20cm tapering to 15cm at the bottom. The section was a naca 0010. It worked very well. you could go a little shorter but with less than 40cm in the water you have less margin for error. If you have a dagger blade style stock you can also sail with the foil lifted a few cms if you want less drag.
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Tasteful paintjobs aren't always a faux pas, Born Slippy is looking superb these days. However if you do drag out the tartan paint you could rename her the" flying haggis "
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Can you send a picture? Less than 60cm in the water is v little. I wonder if your rudder once was longer but broke and was refashioned into a smaller one?
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I've just been out to take a few photos. It's hard to get an exact measurement but I'd say there was no more than a foot in the water, assuming the hull was flat in the water. Secondly there is no (vertical) taper on the blade at all, just a flat cut so the broken blade idea sounds good so far. Hopefully the images will come out ok. . .
Hmmm no images - is there a restriction on the forum software for newbies to post links?
The blade and flimsy (now broken) rudder stock
(http://hxxp: hxxp: hxxp: http: i332. photobucket. com/albums/m351/nickbristol_2008/IMG-20110906-00113. jpg)
http://i332.photobucket.com/albums/m351/nickbristol_2008/IMG-20110906-00113.jpg
Approx waterline when hull is flat in the water
(http://hxxp: hxxp: hxxp: http: i332. photobucket. com/albums/m351/nickbristol_2008/IMG-20110906-00112. jpg)
http://i332.photobucket.com/albums/m351/nickbristol_2008/IMG-20110906-00112.jpg
Anyone got a longer blade and stock for sale?
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Tasteful paintjobs aren't always a faux pas, Born Slippy is looking superb these days. However if you do drag out the tartan paint you could rename her the" flying haggis "
Actually I think I swapped the tin of tartan paint for a long weight some time ago. . .
Talking of renaming, she will be renamed and currently open to suggestions. Due to a slight obsession with The Inbetweeners front running name is "Bus W*****s!!" On a slightly more sensible and perhaps less offensive level "Spirit Level Bubble", "OMG There are fish in there!" (genuine quote from Mrs while snorkling) or "It's me or the Cherub"
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I fully support the inbetweeners idea. Being 17 helps there
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I fully support the inbetweeners idea. Being 17 helps there
Unfortunately I'm exactly twice your age! Mentally, probably not tho.
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This might be helpful when you rename her.
http://boatsafe.com/nauticalknowhow/rename.htm
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Your rudder stock can be fixed and the blade extended at a sticky weekend. Watch this space!
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I've just been out to take a few photos. It's hard to get an exact measurement but I'd say there was no more than a foot in the water, assuming the hull was flat in the water. Secondly there is no (vertical) taper on the blade at all, just a flat cut so the broken blade idea sounds good so far. Hopefully the images will come out ok. . .
Hmmm no images - is there a restriction on the forum software for newbies to post links?
The blade and flimsy (now broken) rudder stock
(http://hxxp: hxxp: hxxp: http: i332. photobucket. com/albums/m351/nickbristol_2008/IMG-20110906-00113. jpg)
http://i332.photobucket.com/albums/m351/nickbristol_2008/IMG-20110906-00113.jpg
Approx waterline when hull is flat in the water
(http://hxxp: hxxp: hxxp: http: i332. photobucket. com/albums/m351/nickbristol_2008/IMG-20110906-00112. jpg)
http://i332.photobucket.com/albums/m351/nickbristol_2008/IMG-20110906-00112.jpg
Anyone got a longer blade and stock for sale?
There is a restriction for the first few posts, we were geting a lot of spam links for a while. Looking at your post count you should now be through the threshold.
(http://i332.photobucket.com/albums/m351/nickbristol_2008/IMG-20110906-00112.jpg)
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Your rudder stock can be fixed and the blade extended at a sticky weekend. Watch this space!
I think the stock is beyond help to be honest. It was thin cheap aluminium and has sheared through - it never looked all that strong to start with.
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I have a Rondar stock of the same era - you are welcome to see if the blade fits it...
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Thanks - I'd appreciate that, let me know how much you want for it.
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I have a good length carbon blade with pintels and fixed carbon tiller for sale if interested? I am also Bristol area based.
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Thanks for the offer GT - longer term I might be tempted if it's not a quick sale you're after.
What is the current consensus on fixed vs lifting rudders? And is a T Foil really that impressive?
I'll probably try and build a new blade, plus or minus a stock & tiller, over the next few months. Including coming along to the Sticky meeting in November, assuming I'm back from Bali in time. Alternatively I might use that as an opportunity to replace the daggerboard as the current one has a large chunk out of it, although it's been fairly well repaired.
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A t-foil is that impressive and can lift about 70kgs when the boat is moving at speed and the foil is at the right angle. This makes the boat think it is lighter and despite the drag from the foil, allows the boat to plane in lower wind speeds than without. The t foil is also a great stabiliser damping out roll and pitch motions. Consequentially it is under high loads especially when you get things wrong.
A t-foil needs adjustment to control the angle of attack. This is currently done by either pivoting the rudder stock around a fixted rudder pin or pivoting the whole gantry around the transom of the boat. i think that there is an article on the main web site under the technical area.
To get sailing this winter I recomend just starting with a normal rudder and enjoy the boat. Then you can decide if you want to spend the additional time building a t-foil system. It is very easy to spend months modding a boat and not actually do much sailing in it.
Do come to the sticky week end. If you have decided what you want to do we can get quite a bit done in a weekend.
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The article that Phil mentions can be seen:
http://www.uk-cherub.org/doku.php/tech/t-foil_systems (http://www.uk-cherub.org/doku.php/tech/t-foil_systems)
there are quite a few pictures of the different systems used, the most common system on new builds seems to be the rotating gantry.
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Great articles. I am being more and more converted to the idea of the t-foil, but need to walk prior to running so will restrain my enthusiasm for a few months yet.
While I remember tho - one of the articles in the link above was members only. How do I get my membership upgraded to see this?
Phil, good advice and very interesting, thank you. I'd love to get sailing this winter but I don't think it will happen, at least not in this boat. The boat is still very much a work in progress and I get very little spare time to work on it. I always envisioned working over the winter on it as it should (just) fit in my workshop / tip / hideaway.
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While I remember tho - one of the articles in the link above was members only. How do I get my membership upgraded to see this?
Done, you just need to make sure that you are logged in to the website before you click on the members only link.
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Cheers Phil, will take a gander now.
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Just read the "T foil rudders - a complete guide" and am definitely sold on the idea of a T-foil now!
One thing that immediately struck me is why just a single T? Would it make any sense to have an additional smaller (less prone to breakage during heeling) T closer to the surface to increase energy recovery but which should not interfere with the laminar flow deeper down for the displacement reduction.
Or is that me missing something crucial?
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As you will know the horizontal foil can be set at the bottom of the rudder or part way up it.
With the horizontal foil set part way up you can't raise the foil so high in the stock for launching and recovery. That's the practical bit.
The science bit is that it is more efficient to have a larger single foil than 2 smaller ones. Less tip losses.
as an example we don't see many bi-planes these days and most modern hydrofoil craft avoid ladder foils (which have several lifting foils).
Cherubs being light appear to work best with the foil deep in the water. There is less need to recover energy from the wake because a cherub planes early and doesn't have much of a wake.