Crowther design 85

Discussion in 'Multihulls' started by Cjk, Mar 3, 2011.

  1. Cjk
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    Cjk Junior Member

    Hello.
    I am considering purchasing a Crowther design 85 cat, I understand they are a little old school but I really like the design.
    I know they come in several makes over the years, I am look at purchasing one built in 1993, so I gather it's an mk 2.
    I'm after any general info anyone can throw at me about these boats, it's going to be used for sailing about the south pacific.
    Mainly what I am interested in knowing, is speed these cats sail at in all sorts of weather, reaching, dead downwind, upwind etc.
    Also can they have a rotating rig fitted to them fairly easily? Or is it a major refit?
     
  2. sandy daugherty
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    sandy daugherty Senior Member

    Does the helmsman have to look thru the bridgedeck to see forward on this design? That means there are two sets of windows to distort the forward view, and a popular place for people to stand in the way. All that can be dealt with but adds complications to a fundamental function.
     
  3. Cjk
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    Cjk Junior Member

    There is two sets of windows but there is also a hatch for the helmsman to stick his head through to get a better view.. This example also has another helm station to port.
     
  4. waikikin
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    waikikin Senior Member

    Cjk, about your rig, best to have Allyacht spars or David Lambourne for example, to have a look at it- by photo if your a distance, rotating may not be that difficult if its already a three stay rig with diamonds, some older boats had caps, inters, lowers, inner fore & forestay, babystay & twin backstays, the placement of chain plates being the consideration although by no means insurmountable with some extra structure + $ of course.The gains may not be worth the bucks, rotating rigs have their issues also.
    I think a Crowther design of that vintage may well out perform many currently available cruising cats. All the best from Jeff.
     
    Last edited: Mar 6, 2011
  5. Corley
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    Corley epoxy coated

    Crowther catamarans of that time had a strong focus on seaworthy and seakindly hull shapes and good bridgedeck clearance which produces a much more comfortable motion to windward with much less slamming than most more modern catamarans where you pay is a bit less accomodation and volume for a given length.

    One of our club members has a Crowther Spindrift "Cascades" which is a very comfortable and has good performance and in many ways is a similar style of boat. It's a bit hard to make judgements about speed because in a cruising boat you are often reefing to a comfort level rather than a speed but you would expect to often see mid teens on the speedo and you can have great confidence in pushing these cats quite hard in tough conditions.
     
  6. Cjk
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    Cjk Junior Member

    Hey guys,
    Thanks for the replies I really appreciate it.
    Walkin: I don't have any experience with rotating rigs, when you say they have their own problems, could you identify what the main issues are?

    Corley: When I ask for speed judgements, I guess I am asking if there is anyone out there that has had direct experience with the design, they are a fairly common boat, at that I'm not looking for number to come and beat people over the head with in 3 months time when I can't quite get to the number quoted, just some vague ideas.

    I did find out some info on this boat today, I found someone at Southport yacht club that used to own one, he swears by the design as a cruising boat but sold his 5 years back, they do have quite an interesting history, there were 4 major variations in the design which were evolutions as time went on, with the last one coming from Stuart Bloomfield in 2000 sometime while he was still at Crowther. They were originally a 43 footer with the second one switching to 49ft. The guy at SYC today said it has the same basic rig in it as Crowther design 150, I think What's up doc, is a 150, a few of them have been fitted with rotating rigs.
    They seem like a great cruising boat but before I put a deposit down I still want to know more about them.
     
  7. Corley
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    Corley epoxy coated

    In general rotating rigs are of a heavier section than their fixed counterparts this is due to the additional loads they have to carry when the mast moves away from a fixed position this can also mean additional spreaders and complication in the rig to attempt to keep the mast in column.

    It could be worth getting in contact with Allyacht Spars as they have a program to check what type of mast section/spreader layout is required for your application it wouldnt surprise me if they have done quite a few masts for Crowther design 85's over the years.
     
  8. waikikin
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    waikikin Senior Member

    Corley has pretty much covered it, the problems are that as usually a three stay rig a matter of rudundancy- ei if you lose a stay it all comes down, & some slack is appropriate to allow full rotation so you live with that or suck out the slack & something else to play with which is no big deal- plenty self adjust thru tacks anyway.
    The evolution was usually seeking more space & load carrying over the original- typically spacing the station molds & wedging of aft 2/3rds, not deducting the core thickness or bearding line off mold stations, adjustment of core thickness up in hulls , underwing & deckhouse roof span etc, increase in centerline beam of hull separation & associated connective bulheads laminate schedules to suit these, later boats some had styling change from the trunk cabin to more streamlined. Boats set up for a three stay rig had extra uniglass laminated to inner & outer skins between the mast bulkhead & companionway/deckhouse bulkhead + a chainplate "knee" or mini bulkhead.
    Again often probably a "better" boat than some more "modern" offerings.
    Regards from Jeff
     
  9. Cjk
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    Cjk Junior Member

    Hey guys
    Again thanks for the replies.
    Speed wise I am still a little at a loss as to where this boat sits, is there anyone that has any direct experience from sailing on a design 85, that can shead a little more light in the sense of providing raw numbers, but that I mean in 30 knots upwind, broad reach, dead downwind etc..
    I know this is hard to provide I understand this, I just want some vague numbers to go by.
     
  10. Cjk
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    Cjk Junior Member

    Well I got my answer, I was at a local Marina this morning when one came in of the same design/make the rig looked roughly the same, they were saying they only recently got back to Australia from NZ, upwind in 25 knots were getting 10 knots of boat speed, and 15 knots on broad reach, I didn't ask what sails they were using at the times, but it answers my question.

    I did call all yacht spars in Brisbane, they didn't provide me with an exact quote but said if I budgeted $45k pretty safely would get a rull rotating rig, installed ready to go.
    I would need sails but that's something I haven't looked into the cost of yet but will in the coming days.

    Also interestingly enough when they left NZ back to Brisbane, they left at the same time as a Schionning 50ft (didn't mention what exact design), they beat the schionning back into brisbane by a full day. That's pretty impressive given the age of the design.
     
    Last edited: Mar 8, 2011
  11. catsketcher
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    catsketcher Senior Member

    Why go rotating?

    At the risk of a flame war with a few of my regular combatants I would urge lots and lots of caution in changing the rig and going rotating.

    As you already say the design has just come back from NZ in a very respectable time. My 2 cents worth would be that offshore you will usually be slowing the boat down OR going as fast as you and your crew can take. Racers aren't like this - they push as hard as they can and damn the consequences.

    A rotating rig on such a large boat will make your heavy wind sailing seem much hairier and scary. The rig will thump and sway as you pound to windward and so you will slow down to reduce this. Also you will lose the fabulous inner forestay you already have which is a godsend beating back south down the Queensland coast - put the staysail up and clip along.

    I had a rotating rig on my 31ft cruiser and didn't go rotating on my 38ft cat. I am very happy to be rid of the worries, the noise, the nasty spanner, the huge loads from the rigging snapping tight in chop and I go as fast as I want.

    On top of this you also will have to do a huge (read expensive) amount of work to reposition the chainplates. You may even have to put new bulkheads in position to take the loads. To do this on an already built boat with an interior - OMG.

    Put nice sails on it and go sailing. It will do really well. Remember Lock didn't have a rotating stick on Deguello, Ian and Cathy Johnstone pulled down their rotating rig on Bullfrog and put up a taller non rotator. Pin your ears back, tidy up the solar panel mounts, roach the main a bit but don't go rotating unless you have a huge amount of money and want to do it just for looks. My bet is you won't go any faster than a well sailed normal rig.

    cheers

    Phil
     
  12. Cjk
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    Cjk Junior Member

    Now that's the sort of reply I had been looking for on the rotating rigs, until then no one had given anything but positive opinions on them..
    When you say beating into the wind you say the rig will rotate quite a bit, I was led to believe that there was a way to fix the rig in place in such conditions.
     
  13. catsketcher
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    catsketcher Senior Member

    You can use a spanner which restrains the rig but no rotating rig will be as tight as a non rotating rig. If you tighten the rig tension too much the mast won't rotate but even worse is the effect on mast bend. As the crane is always out the front of the stick it exerts a large compression force on the front side of the mast. This forces the stick into a reverse bend. So you whack some tension on the diamonds to pull it back and give it a bit of normal bend. If you pull the same amount of forestay tension I that I can on my non rotating rig then the mastmay not rotate properly and you won't be able to get the reverse bend out with the diamonds. This makes rotators a softer rig.

    So upwind in a bit of a blow the lee stay gets a little loose and then you can get some disconcerting characteristics. Go sailing on a Hobie 16 to get a feel for a rig lolling around and how the stays stop the mast swinging with a bang. Its bad enough on a 16footer or a 35 footer but I would stay well clear of it with your boat. The race boats of 44ft may have rotating rigs -Bladerunner for instance but they have a totally different rig configuration.

    For one they are probably about 1/3 the weight of your boat (when cruising). The Bladerunner I sailed on could lift a hull in 12-15 knots. So the rig is under much less load with reduced stability. Then again they have a typical three quarter rig sailplan. Unless you move the mast forward - and although you can move a chainplate you can't move the mast on a cat without a total rebuild - you are going to have too big a headsail for a typical three quarter rig. This means your forestay loads will be too big and the only proper way to get rid of headstay sag on a typical rotating rig is with mainsheet tension. So after every tack you will have to wind up the mainsheet with probably well over the boat's displacement to get the forestay somewhat tight. You probably won't so the forestay will be so loose that you will go to windward slower than a sistership with the designed rig.

    I just got out my design book and saw that 85 has the mast halfway aft - this is a killer for the rotating rig because of the above sailplan reason. The rotating cats all have masts further forwards with reduced jib sizes. Remember Lock drew very nice rotating rigs on many of his boats he was drawing at the same time and Lock was the best designer we have had. He didn't put one on this design because it didn't fit in with the design criteria - it still doesn't.

    So lets assume you want this design but more speed - go the screecher. It will add sail area that you can use almost all the time in lighter winds. It is much much cheaper and easier to do. You go sailing straight away. You keep a bulletproof rig for ocean sailing and have better resale. In very light winds directly upwind most cruisers wait or motor slowly so the very light upwind performance can be neglected. For everything else a screecher, nice sails well trimmed, keeping the bum clean and keeping her light will work very well. A watermaker will save hundreds of kilos too. There are other ways to get more speed than the mast.
    cheers

    Phil
     
  14. Corley
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    Corley epoxy coated

    The whole issue of rotating masts seems to not be clear cut for example the two top farrier folding tri's in the club are a good case in point one has a rotating rig the other fixed, theoretically this should make a significant difference but in races the rigs could be interchangeable as far as performance. Most races are decided on who judges wind shifts best and are in the right place at the right time. For a racer trying to eke out the last bit of performance on an off the beach or racing boat the rotating mast is worthwhile for everyone else I'm not sure. The situation where I could see a lot of difference would be if the boat carried a wingmast with a large Chord and these are the province of racing boats only.
     

  15. Gary Baigent
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    Gary Baigent Senior Member

    Catsketcher, I agree that altering Lock Crowther's original fixed rig design is not a good idea; as you say, having to shift mast position, changing forestays to 3/4ers, chainplates etc. - but I find your comments about rotating masts "thumping and swaying" somewhat strange. I guess it depends on the weight of the rig, because I'm sure an overweight rig, either conventional or wing mast, will tend to take control ... but on the rotating rig boats that I've sailed on, (which if anything, the masts have been as light as or even lighter than conventional masts, referring to wing masts here) I've never noticed this problem. "Thumping" suggesting that the rig is set up very loose, or that the rig is overweight.
    Also there is no reason to have to get rid of your inner forestay - you just set up a rotating mast inner stay the same as the hounds beak fitting for the upper shrouds and stay. Maybe there's your answer to your thumping and swaying problem, the inner and the lowers keep the rig nicely controlled. Also I have adjustable stays, block and tackle, and you can adjust your rig to whatever shape you want. Plus, any rotating rig requires runners, imo- they do a great job of taming a rig. Your swaying problem also sounds like your spanner control is not doing its job ... again, set up correctly, with the spanner rotation controls cleated, there is no way for the mast to flop around. One slight disadvantage of this is that you have to readjust them if you tack or gybe. Also you've got runners to halt swaying backward and forward.
    There is still a lot of nonsense spoken about rotating rigs and I'm not saying you're included - because you're relating your own valuable, hard won experiences ... but there are always solutions.
     
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