UK-Cherub Forum
Cherub Chat => Tech Chat => Topic started by: Team Slatter on June 10, 2014, 09:22:53 AM
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When sailing Spanish with Eddie on last Saturday we discovered some difficulties due to the strange shape of the hull. It seems that it has a narrow entry at the bow but then widens really quickly at the bottom of the boat. Thus creating a barge like effect. I think this is what slowed us down at the Nationals whereas other boats slice through the waves Spanish bashes through them unless we are on the plane.
Anyone on the forum got some sailing tips for this type of hull shape especially as I am carrying a heavy crew and helm ? or should I look at cutting and trimming ?
Also, who has the all the designs of the boats ?
Regards
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Many of the designs are on the wiki page.
There is a knack for getting a cherub upwind. The general advice is that if you are not planing put the nose in deep and steer for the waves. Born slippy/Atum are probably fatter in the bow than yours and yet can still sail fast in this mode. Remember - keep plugging away at it and it gets faster.
When I sailed her with the old rig at Draycote she felt very smooth through the transition and fairly slippery through the water. Time in the boat will make you faster than any hull mods/ cutting /sanding.
Cherubs are not the easiest of boats, but the pay off is electric and that is the point of 12ft dailing :-)
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I think Spanish is a Pasta Frenzy design from the mid-90's. You are correct that your boat is wider at mid-length than the post-97 rules boats. When Spanish was built there was a rise of floor at mid length rule in place to stop people building super-skinny boats. At the time the Moths were getting narrower and narrower, faster but increasingly difficult to sail. The feeling in cherubs was that we wanted to make sure the boats were still sailable by two normal* people. Post-97 the rule was changed to a minimum chine width rule, but there is now no restriction on where that minimum chine width is placed. Designers have tended to push the widest part of the boat aft towards the transom, making the middle of the boat skinnier.
It's all a trade-off. You will probably lose out a little bit going upwind in displacement mode due the slamming effect of the fuller bows. But downwind as the wind increases you should plane erlier. The Pasta Frenzy has a very flat bottom towards the back end - I think there is basically zero rise of floor at the transom - which should give you a very high potential top speed on the plane compared to other boats.
Like Roland I would avoid trying to modify the hull. You will lose several months sailing time and the hull could easily end up heavier than before - not a good thing. The same time, money and effort tuning the rig and foils would pay bigger dividends.
*Normal is a relative term
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Now that I think about it, wasn't Dave Roe going very quick to the windward in the original Pasta Frenzy at the Nats 3 or 4 years ago? I'm sure he was first to the top mark at least once with a 97 Rules rig on. If you have the ability, it's possible to pedal that boat upwind very rapidly indeed.
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Davro's 'original' Pasta Frenzy isn't very original any more Neil ;)
Agreed though, I don't think that it is the fault of the design as it is a development of the Bistro and so should be a fair bit quicker over the water due to its refined shape. It is a lot wider at the bow than the new boats though, you are right there.
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strange shape of the hull.
What?
Thus creating a barge like effect.
Are you actually using the word barge to describe the sailing style of the pasta frenzy?
I think this is what slowed us down at the Nationals whereas other boats slice through the waves Spanish bashes through them unless we are on the plane.
Two of the 97 rig boats who beat you, Numb and Madge, are Bistro designs, the design by Dave Roe that your boat is an evolution of, your hull is not the problem
or should I look at cutting and trimming ?
No
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Thanks Tim, I will be visiting the water as regularly to adapt and enhance my boat handling skills in preparation fr the nats
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I agree with the 'dont mess with the hull' statements. Every boat has its own 'sweet-spot' and after time sailing you should eventually find it and go a lot faster.
If you look at the recent hull pictures of Fuzzy; I think it is also quite boxy towards the front end and the chine line is ever-so low. It is very low on rocker line like the more modern designs.
I also think Sweet Dreamzzz is narrower at the front end and, being a slightly older design, has has a lot of width mid section. SDzzz also has a lot more rocker as well. I think it is this that contributes to the foe-aft trim/balance being crucial for speed and stability. SDzzz is a light wind flyer but very prone to 'cleaning out the sluices from both ends' if you get it wrong. Paul and I did a 'cherub salute' at Pwhelli and Joe and I went the other way with a good nose plant at Rutland.
Having said that we were starting to go a lot faster upwind thus the realisation of a lot more practice needed... but Fuzzy is ready to tame now! ;D
Have you seen the line drawings on the boat details pages? That gives a good insight and impression of the hull shapes.
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Remember speed is king and have to keep your cherub trucking in it's grove. The trick we found back in the day was lots of tiny movements and keep the weight forward. Cherubs have 'as near as dam it' to no rocker so they drag the transom very easily. A good rule of thumb is if the wake isn't smooth from the back of the boat then you have probably got your weight to far back.
Davroe was always fast to windward!
Time on the water makes the biggest difference to speed.
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Time on the water makes the biggest difference to speed.
This should be meditated before making any changes to anything!
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Dive in with the chain saw. You will only learn by making mistakes.
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Good idea about chain saw. Cats not allowed! ;D best to have 2 boats though. 1 sail able other in the cutting shed.
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Hopefully there will be a second boat in the coming summer/ next year
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Do not blame the boat ,it is usually due to the nut on the end of the tiller !!? I will be there when wreck n effects fittings put back on.
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now then... 'wreck n effects' more info requested. what boat is this? nd is this a new thread?
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The hull is unlikely to be the problem.
It sounds like it is light winds that are the problem.
So my tips are;
Most people that are slow in light winds are because they think they are. Consequently they stop concentrating and then say I told you so.
Focus on what the boat does and not what others do. The first place to look is nose transom out maybe a little heel and T-foil a little positive to adjust for pitch.
Sails and need to be open and a little flatter than you would think.
and above all practice
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What is your crew weight Alex?
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I am 75kg and dad is 80 kg's
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I haven't learned much yet about making a Cherub go fast but light weather = get that nose down further than you dare then back it off when you are definitely being stupid. The sweet spot is probably about there.....?????
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Dave and I were a similar weight in the 05's at the nationals. More power will help but weight is not a big factor between boats in light winds. Keeping the transom out or on the surface will make a big effect. Heeling an E5 much digs the leeward chine in and also creates drag so look at the wake at the back for clues.