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Thread: Simply put, "More Speed"!

  1. #1

    Default Simply put, "More Speed"!

    Hi,
    i'm Petter and i am fairly new to the forum and have been doing a little posting and a lot of reading. We, the family is on an extended cruise around Europe and we are at present in Northern Cyprus for the winter.
    This thread is meant to be about what i have to do to get more speed out of our catamaran.
    My problem is that the " window of comfortable sail" is too small!

    Our boat is a FP Antigua37 from 1993. She has about 70 m2 upwind sail, she weighs, not 4,5 as said in the brochures but rather 6-6500 kg all aboard.

    When i say that the window of sail is too small i mean that from very little wind and up to about 12 knots she is sluggish and we often persuade ourselfs that we have to use an engine because we probarbly have to charge a bit or run the watermaker anyway... And i hate that! I want to sail not motorsail!
    Again, the reason for running an engine is not that we are in a hurry, its because the boat is so much more comfortable with the extra knot or tho that the motoring gives, she really streaches out and comes through the waves so much better. And i imagine her doing that under sail alone.
    Stop rant.

    I have three different options that i have been pushing around the table and they can be separate or put together according to your beliefs
    if you you have other ideas they are more than welcome.
    Buying a bigger cat that sails faster is not an option at this point.

    Here we go..

    1, Extend mast from 15,5 meter fixed aluminium to 17,5 meter rotating carbon spar. This way i will be able to have up to 20 more m2 going upwind with almost no added weight.

    2, Extend the hulls to make a longer waterline. I have made drawings where she is a full fledged 42 or 44 foot boat and she could then have a similar Lwl. Some extra weight would enevitable with this option.
    Although running a longer Lwl in some of the formulas availible does not produce significantly higher speeds in light to moderate winds. Does Lwl only count in at the end of the speedrange?
    it would help in tracking and seakeeping though, right?

    3, Daggerboards. She points allright but the leeway kills most of the progress made. Someone mentioned that taking off the LAR's will reduce bouancy and we dont want that so maybe have booth..?

    So, there you have it
    Go easy on me!

    Petter

  2. #2
    Join Date
    Oct 2008
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    Default Re: Simply put, "More Speed"!

    Hi Petter, and welcome.

    Please describe your sail inventory.

    Are you specifically interested in close hauled speed? If you have a small jib, changing to an overlapping genoa will help and be a lot easier and less expensive than your other options.

    For further off the wind consider adding a reacher/screecher/genaker/code 0 on a sprit. Again way easier and cheaper than the other options.

    If you're at this point of considering these significant modifications, I assume you have already unloaded as much stuff as you can.

    2 Hulls Dave

  3. #3
    Join Date
    Dec 2008
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    Millbrook Cornwall UK
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    Default Re: Simply put, "More Speed"!

    Hi Petter and welcome. I've no first hand experience of a Antigua but sail an Azuli F40 which is similar in that its 11.8m long with 85sqm of sail and weighs 5000kg. As you can see the Azuli is lighter by 1000-1500kg and this is your main problem. There was a Antigua that was raced in France (Multi 2000) and its weight was given as 5 tons. It might be worth going through your boat to find if there is any heavy items that you could do without. All of these weights are given for a stripped boat, no fuel, water, food,personal gear or toys, most cruising sailors want a spare for everything. Every little will help. Once you have sorted the weight issue look at the power side, the sails. Carbon masts, although ideal, are hugely expensive and the weight saving over aluminium not as good as first appears once all the fittings are attached. A longer mast would allow bigger sails which is good, it would raise the centre of effort which would make the cat more demanding to sail in stronger breezes, think of a 4th reef. How big are your present sails? Could a new jib be made with more overlap, a larger roach on the main, a longer boom? Best to talk to a few sailmakers but make sure that the are experienced with multis and understand the differences from monos. Increasing the waterline would improve the seakeeping but I can't imagine it would help the performance in light winds, indeed the extra wetted area may slow you further. I have LAR keels and the designer, Erik Lerouge has a polar diagram showing the difference between LAR's and daggerboards for his designs, they are 3 degrees on pointing and 0.1/0.2 of a knot on speed. We race and beat daggerboard boats on the water and even more frequently on handicap, LAR's do work but need good sails and careful sailing, much the same as with any sailboat.

    Cheers,

    Peter.

  4. #4

    Default Re: Simply put, "More Speed"!

    Peter is absolutely correct, it's a HP TO WEIGHT ISSUE. Either reduce weight or incress sail area. Install a sprit and put a screecher out there that change will allow you to get a knot of speed at least.

  5. #5

    Default Re: Simply put, "More Speed"!

    Right, great,
    The Main is 47 m2 and the solent jib is 22 m2, not overlapping. I know the bigger sister the Fiji 39 has a genoa sheeted on the coachroof and i would do that immediately if i new the roof was up to it.
    then we do actually have a code0 on a 1,80 m bowsprit. It goes right to the masthead and is 64 m2. It's a beast and the boat is lovely with it. We run it up to 12-14 knots AWS and 40-120 AWA.
    and last is the gennacker, not sure about area but its also good from 120-180 AWA up to about 20 knots AWS.

    i am interested in getting more speed from the boat on all angles of sail but of course going upwind with a bit of chop you really need that extra momentum of force behind.

    As for weight saving, i'm addicted. Only one anchor, 45M 8 mm chain. Ripped out one watertank and fitted a watermaker saved on average 90 kg, new carbon saloontables saved 20 kg, all dyneema lines saver a bunch, most boat documents only in digital form, new foam sandwich floorboards etc, etc. And more can be done, nothing comes on the boat unless twice the weight is lost somewhere, Anna is counting the kids every night! Ok, slight exaggeration but almost. We have a weight focus.

    So as for daggerboards, pointing another 3degrees feels like its lost in the leeway anyway. What i think i need there is directional stability, ie, a long narrow waterline. But i can also see what you mean by the extra wetted surface slowing the boat down in light conditions.

    The best speed return on a given modification that i have read about is the rotating mast. In at least two different cases it has been stated that it has given 1-1,5 knots more than with a traditional fixed spar.

    What should be my next step?

  6. #6

    Default Re: Simply put, "More Speed"!

    I found we got better light air speed after extending the sterns of our Seawind 1000. The extensions brought the sterns out of the water which gave a clean exit and greatly reduced the wake. Also I would think of adding a square top main. Really ads sail area and puts the added sail area up high where you have more wind.

  7. #7
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    Default Re: Simply put, "More Speed"!

    Petter - well, putting a taller, carbon, rotating rig + new sails on a 22 year old LAR keel FP (how many hours on the engines?) for a little better upwind speed may be considered by some to be an example of a poor use of money. It will definitely work to improve your upwind speed, but the whole boat may be immediately worth less than the money you just put into it. In the rural southeast US we have a saying for expenditures like this: trying to make a silk purse out of a sow's ear. New sails (including sq top main, overlapping genoa) on a longer boom would be effective but less wasteful, IMHO.

    Whatever you do, good luck.

    Dave

  8. #8
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    Default Re: Simply put, "More Speed"!

    Moonskater -
    You don't mention what props you have, but if you're using 3 blade fixed props the cheapest way to pick up a knot (or more) is to replace them with 2 blade folders. I recommend Flex-O-Fold.
    Actually, the cheapest way to pick up a knot is to completely unload the boat lol.
    Sail Fast Live Slow

  9. #9

    Default Re: Simply put, "More Speed"!

    Welcome

    You might consider replacing the SS shrouds with synthetic a saving of 20-30kg high up.

    As previously mentioned folding props will help.

    I have sailed both Antigua and Fiji all be it a while ago. IMO the Antigua is probably faster than the Fiji that gets stuck and maxes out at about 11knots. We have had 13knots out of an Antigua, she was in delivery trim (empty) in strong winds up 40knots but not quick in light winds. IMO the sheeting angles are wrong and you need to sail more open for best VMG. Trimming the blade jib needs a lot of tweaking. Try barber hauling in or out especially when hard on the wind to prevent stalling.

  10. #10
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    Default Re: Simply put, "More Speed"!

    G'day Pete,
    And welcome to the forum! I'm inclined to agree with Dave with looking at your sail plan and not modifying your hulls or putting a rotary rig on for more power. Just how much more speed do you think you will get by doing these modifications? Power to weight ratio to water length governs all of us and too much of any one of these things can see us upside down or with no rig calling for assistance from the authorities. A good friend of mine with more money than sense poured $500k modifying a monohull, carbon rigs, exotic rigging, rudders, keels and stretching the hull in both directions and I think he picked up about 1 and a half knots which gave him say 30 mile a day, not worth it unless you have bucket loads of money. These modifications sound simple, but you will run into all kinds of little issues which will cost $1000 each. And that's if it doesn't end up overpowered for the water length. You may not particularly like running your engines, but at the cost of the modifications, you could probably buy you enough diesel to get you around the globe motor sailing. Speed costs. How fast can you afford to go? So weigh up your pro's and con's and do extensive research on everything if you plan to modify too much of your boat. Alternatively, talk to a smart cat sail maker and see how many more square metres he can get on your boat as is.
    L&N

  11. #11
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    Default Re: Simply put, "More Speed"!

    How old are your existing sails?

    New sails on their own will help and even better if you can get more area.

  12. #12

    Default Re: Simply put, "More Speed"!

    Ooh Dear, i was dreading this;-)
    My wife says "what did i tell you".

    But for arguments sake.
    Our props are 3-bladed feathering Kiwiprops. They give less thrust forward than the original fixed 2-blade but they are a lot better on reverse.

    2hullsdave, the engines were taken to atoms before our cruise, the guy says they are better than new. All, and i mean All wear components are changed. We have since done about 1500 hours coming down the european canals. They (the engines) are in very good condition, better than the canals.

    Peter, yes the standing rigging is a big part of the total rig weight. Our mast is a Z-Spar Z800 extrution at about 10 kg per meter so just the mast tube is 155 kg. I guess the standing rigging and fittings is another 150 kg at least.
    Synthetic rigging, Pbo, Dyneema etc is something i have not had any experience of apart from a short burst on a smaller Marstrom M32 a couple of years back. It feels more in place with a rotating rig for some reason. Shafe is a grand issue here i guess?
    Could you elaborate a bit more on the sheeting angles? She does have a tendancy to stall easily and even if i sail her by the tiller she has a very narrow "sweet spot" where she starts to go.

    L&N, I am looking for the speed equivalent to running one engine while sailing. Or, if i really want to push it, I want to sail at AWS at all angles.
    I am quite aware that the mods are expensive and not appropriate, costwise for an old lady like mine, but she's all i got at the moment. And, its fun to modificate! I'm learning CAD drawing, waccum bagging, resin infusion, Titan welding (did i mention titan tubing in the bimini?). And all sorts of fun stuff. This is also part of the whole shabong.
    If my aim was to travel the globe at minimum expence, i would probably fly.

    And, as many of you are asking. Our sails are due for a change wich only puts the finger harder on the question, should we extend the rig a bit for the new fathead main, raise the forestay a bit, tweek, tweek,?

    One idea is to get hold of a longer aluminium masttube extrution and make a rotating version with this with a lot of the existing hardware?

    Keep it coming!
    /petter

  13. #13
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    Default Re: Simply put, "More Speed"!

    If you go to a rotating mast the whole rig would need to be changed. Rigging tension would be substantially less involving changes to the jib to accommodate the forestay sag, spreaders when rotated interfere with the jib meaning if overlapping it cannot be sheeted in sufficiently. We have the choice of pointing high and dragging the mast upwind or pointing low and fast with rotation, VMG is similar but its all a compromise. The fittings at the stay terminations would be very different to your Z Spar arrangement to enable the rotation. The speed gain on the Azuli when we rotate, I'm sure is more in the region of 0.5knot, but in practice its very difficult to determine. One of the main advantages for me is the ease of reefing the mainsail because the battens are normal with the cars. A couple of disadvantages are the slack leeward shroud, we have slacksuckers fitted and the shorter life of the standing rigging.

    Back to your weight issue, and I'm on delicate ground here, but I have 20m of chain and 65m of Octiplait rope, could be a worthwhile saving. I also always carry a second anchor, a Fortress doesn't weigh too much and works well.

    Peter.

  14. #14
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    Default Re: Simply put, "More Speed"!

    Hi again, Petter. The reason I asked about the engines was related to the overall worth of your boat. Obviously, if they had many more hours and were due for re-build or replacement, this could factor into your decision process. I suspect you're smart enough to have already figured this out. Keep counting the kids and keep Anna happy. That's worth a couple knots right there....

    Dave

  15. #15

    Default Re: Simply put, "More Speed"!


  16. #16

    Default Re: Simply put, "More Speed"!

    Quote Originally Posted by Moonskater View Post
    Ooh Dear, i was dreading this;-)
    My wife says "what did i tell you".

    Peter, yes the standing rigging is a big part of the total rig weight. Our mast is a Z-Spar Z800 extrution at about 10 kg per meter so just the mast tube is 155 kg. I guess the standing rigging and fittings is another 150 kg at least.
    Synthetic rigging, Pbo, Dyneema etc is something i have not had any experience of apart from a short burst on a smaller Marstrom M32 a couple of years back. It feels more in place with a rotating rig for some reason. Shafe is a grand issue here i guess?

    Could you elaborate a bit more on the sheeting angles? She does have a tendancy to stall easily and even if i sail her by the tiller she has a very narrow "sweet spot" where she starts to go.

    /petter
    Replacing the shrouds will reduce weight up high, that will reduce pitching and improve pointing. The only sensible replacement is the main shrouds. The forestay cannot be replaced with synthetic. I used Michael Strong of www.StrongRope.com in Australia to make my shrouds as they are all pre-tensioned. Their very low weight means they can be posted pretty much anywhere.

    As you have found out the blade jib on the Antigua has a very small performance envelope. Once outside of this there are shortcomings. This is mainly because the sheeting points are not adjustable enough. You can improve this by fitting eyes or using strops attached to the toe-rail, cleats, mast-base etc. and using a "handy billy" with a loose, opening snatch block on the end through which you feed the sheet. By adjusting this you can change the position of the sheet lead to the sail and control the shape over a wider set of conditions. Remember that you can use this to reduce the sheeting angle, with an attachment from the opposite side of the boat, as well as increase it.

    If you are planning new sails anyway I would recommend 110-120% jib and fitting tracks to the coach roof. If I remember correctly the later Antiguas changed to this arrangement.

    Peter (there are far too many Peters involved in this thread)

  17. #17
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    Default Re: Simply put, "More Speed"!

    Hello Petter,

    IMO most cruising catamarans are overloaded with supplies and toys, and should be lacking performance in this wind range.
    Else you are doing something wrong! (minimalist racing).
    You mentioned you are diligent with weight, and have feathering props. That leaves the other options, dagger boards, extended water line, extended rig, shrouds, new boat, etc...
    Except for mandatory sheeting experiments, all seem very expensive, difficult, and time consuming. And not guaranteed.
    I believe the issue is to windward only? Someone mentioned a screacher. Perhaps this is an instant fix???
    Do you have a downwind chute/asymmetrical. Not sure if this direction is issue???

    My pet peeves are with holes in the dead downwind performance - 5 -12 knots true. And then again at 18 -24 true. I would buy two Symmetricals for those situation. But only if I was on an extended Pacific/World cruise...
    IMO is to use the diesel, relax, enjoy the time...
    cheers

  18. #18

    Default Re: Simply put, "More Speed"!

    The Azuli looks a beautiful boat and what i'm really trying to do here is to get into these same relations between weight, sailarea and Lwl. Since i dont know where i would be able to cut1-2 tons of the weight of her, i'm instead trying to go the other way, make her a bigger boat so that she will fit the weight. do i make sense?
    If you for example disregard knowing what type of boat we are talking about and i would describe her as;
    43 foot boat, 42 foot waterline, Lwl/Bh >11, 62m2 fathead main, 30m2 genoa, 64m2 Code0 on prodder, etc, it dont sound too bad...right?
    I know i'm fiddling with resale value but i honestly think i could make the mast and Hull extentions for around 20K. Not counting labor. I'm in manufacturing and anodizing aluminium so there are good oportunities to get things done.
    the boat is not gaining value anyway, so what the heck?
    I did have a great read on an old thread on hull extentions started by Dennisail i think. That was really about what people thought about extending with wave piercing bows on an existing design., really entertaining but many missed the point wich was that there already was an existing boat to fiddle with.

    Peter, I'm Petter so there is only you and Lillywhite so far. I take it that no internal supports had to be made when mowing the track up onto the coachroof. For a track of say 600 mm i would cut out the foam from the inside and glass in a 600 by 120 solid support, add a aluminium washer strip of 600x30x4 And thats it? I like this idea better than tweeking the solent jib with in and out ****ers (the things you describe are called that in the swedish racing comunity).

    Peter-Lillywhite, the anchorissue is a tough one, with the 45m 8mm and also some rode on our Spade anchor, we have dragged at one time in gusts over 50 knots. When cruising like we do now i'm not willing to go lighter here. When we are back in more familiar waters we might. The Fortress was on the packinglist up until one week before departure and then had to stay home. Have not missed it yet.
    Does a rotating mast benefit from double diamonds to minimize the width of the setup to be able to sheet closer?

    Ixenophon, Yes some of my friends laugh at me for saving a kg here and a kg there "and then you bring diving tanks!"
    But the idea is to carry the weight i want to carry, not the other weight. There is no point in carrying a 30 kg saloontable, it does not make it a better table. The new tables weigh 6 kg. Taking out the smaller 180 litre watertank saved an average of 90 kg (tank on average halffull) and made "room" for the watermaker and some other toys. I'm not sure what you mean when you say that my boat should lack performance in light weather?
    My issue is speed on every angle as you can read above, the Screecher or Code0 is already in place.
    /petter

  19. #19
    Join Date
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    Default Re: Simply put, "More Speed"!

    Petter,

    I suspect from following your thoughts as the thread progresses that if you are going to stay with your vessel the best option is increasing the waterline length perhaps both bow and stern to carry your load.

    Quite a few others apart from Seawinds have done it successfully as as you will be doing the work it should be the most cost effective option.

    Cheers

  20. #20

    Default Re: Simply put, "More Speed"!

    Downunder, yes the drawings i've made has a vertical or wavepiercing bow extending 650-700 mm. The stern is extended 850-900 mm wich gives a total of about 1600 mm and a total boat length of 12,900 mm or 42,3 feet.

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