BIPOLAR

Build logs from members building catamarans, trimarans and other multi-hull variants.
mahnamahna
Posts: 580
Joined: Wed Aug 02, 2006 4:48 pm
Location: Gosford NSW

Re: BIPOLAR

Post by mahnamahna »

I must have misunderstood your discussion with me Michael, I mistook you to mean that now that the mast is more fluid in its rotation as a result of you lubricating the bottom bearing you now dont need to use the in boom winches to trim boom to mast angles.

Hopefully Mike (Whimsical) will join the conversation, because I am led to believe he wont be adding any boom to wing angle control and I am inclined to not do so either for no other reason than I would have no idea when I would need to deploy such control or to what extent and certainly not just to wring out a little extra speed for the sake of maximising capabilities.

I am not only not a sailor I have no real interest other than safety to become one. I am building a boat to cruise only because I dont have the wealth to fly around the world and stay in hotels, I have no interest in sailing for the sake of sailing it is just a means to an end for me, I derive no pleasure from it. In fact I see it akin to driving, moving the boat from one nice mooring spot to another would be like driving a motorhome from one nice place to another. So I have no real interest in "tweaking" for performance. If I had the money for the fuel to motor around indefinitely I wouldnt bother with masts and sails at all. My perfect boat would be a solar powered electric motor boat capable of motoring all day on the power of the sun.....perhaps one day until then, I have to contend with all this tacking, gybing and pulling on strings crap.

If on the other hand, it is a safety issue and can depower the boat when no other means is possible or it is a stress issue on certain parts, what I mean is, without controlling the wing to boom angle I am likely to break something or even prematurely wear something out, then of course, but if it is only to achieve 7.5 knots when I am only able without such control to achieve 7 knots then meh, I dont much care. There is of course the possibility I may in time learn what such control means to performance and safety and may wish I had it, but I doubt it if it does not contribute to safety and only to maximise performance.

Groper, the original Schionning idea for the masts was a socket tube glassed into the boat into which the mast would sit and I cant remember if they changed their minds to go to a post so that the deck would be sealed or whether Rob and the new engineers added that idea. I think I prefer to have the deck sealed to the post rather than have a tube into the boat open to the elements and covered with a sock, water always finds a way in and I would prefer not to have to worry about drainage etc.

At times I have wondered whether to contact Derek Kelsall about building my own wing masts, he seems very confident of his method being cheaper, and easy enough for anyone to do well. But with the shorter masts now I suspect the cost will come down somewhat and that they become within my ability to pay for and will be my best option. I have also toyed with the option of plain round masts. Sean in Qld has round masts. The wings at times sound like more trouble than they are worth, remembering, I am not the least bit interested in having the fastest boat in the harbour.

I spoke to a guy at SC boat show a few years ago about in boom furlers but the cost of boom and sails to suit (you cant just put any sail shape on an in boom furler because of the battens) came to over $12000 each, beyond my budget unfortunately. And it concerned me that it would also be adding another thing that could jam, or otherwise fail.
groper
Posts: 239
Joined: Sun Nov 18, 2012 11:23 am
Location: cairns

Re: BIPOLAR

Post by groper »

Yep for sure on the roller furling booms, i know they are dear as poison...

If your not interested in trimming the wings, i think you will be once your up and sailing... The rig size can be reduced significantly if you have an efficient rig - this is why Micheal.O. can get away with chopping so much off his masts, and there is still plenty of power there - provided they are trimmed well. So if you ignore the wing rotation control, your dealing with more sail area to compensate. If your happy to have the small area, ignore the trimming, and just go slow, well now your spending twice as much time "driving to get there" instead of arriving at your anchorage and spending the time where you want to be... We shall see once your on the water :)

I got the schionning study plans which show the main bulkhead we are talking about next to the masts at 3300mm from the bow - so its all good, cheers anyway. My bulkead is at 3100mm from the bow - so its pretty damn close to exactly the same distance once you scale down for my smaller boat... I have to reduce the boom length to no more than 4m so they clear the lee mast - as i have less overall beam also. All in all it seems entirely feasible to adapt this rig onto my boat, much less work than any other type of rig.

I had to do a rendering to see what it looks like. Ive also included the area details so i could find the center of effort - which is shown as 5.45m - dead center of the LWL once i extend the transoms- perfect! These masts are 12m above deck - but remember i have shorter booms so less area than Michael`s cut down masts... Ill Tweak the centerboard location once i size the rudders and thats that... sorry in advance for the thread hijack! :mrgreen:
44c
Posts: 1148
Joined: Tue Aug 08, 2006 5:08 am
Location: Hervey Bay, Qld

Re: BIPOLAR

Post by 44c »

mahnamahna wrote:I must have misunderstood your discussion with me Michael, I mistook you to mean that now that the mast is more fluid in its rotation as a result of you lubricating the bottom bearing you now dont need to use the in boom winches to trim boom to mast angles.

Hopefully Mike (Whimsical) will join the conversation, because I am led to believe he wont be adding any boom to wing angle control and I am inclined to not do so either for no other reason than I would have no idea when I would need to deploy such control or to what extent and certainly not just to wring out a little extra speed for the sake of maximising capabilities.

I am not only not a sailor I have no real interest other than safety to become one. I am building a boat to cruise only because I dont have the wealth to fly around the world and stay in hotels, I have no interest in sailing for the sake of sailing it is just a means to an end for me, I derive no pleasure from it. In fact I see it akin to driving, moving the boat from one nice mooring spot to another would be like driving a motorhome from one nice place to another. So I have no real interest in "tweaking" for performance. If I had the money for the fuel to motor around indefinitely I wouldnt bother with masts and sails at all. My perfect boat would be a solar powered electric motor boat capable of motoring all day on the power of the sun.....perhaps one day until then, I have to contend with all this tacking, gybing and pulling on strings crap.
You'd be just as well off to launch the boat without a rig then. Fact is, a rig and sails, plus all the associated gear, winches etc, AND the added cost of building the boat strong enough to carry a sailing rig, costs plenty. Plus there are daggerboards and cases, and rudders big enough to steer a sailboat.... it goes on and on.

Especially if you're having twin carbon masts and two (fully battened, with battcars, tracks etc) mainsails!

You probably wouldn't get much change from $100,000 when you add it all up.

That would buy you a lot of fuel! A slight upsize in motors, and bigger fuel tanks, and you'd have a very efficient motorboat. You'd certainly be able to get around 2nm/litre, cruising at around 7 knots on one engine.

You'd have to go a long way before the rig and sails started paying for themselves.
mahnamahna
Posts: 580
Joined: Wed Aug 02, 2006 4:48 pm
Location: Gosford NSW

Re: BIPOLAR

Post by mahnamahna »

44c wrote:
You'd be just as well off to launch the boat without a rig then. .....

A slight upsize in motors, and bigger fuel tanks, and you'd have a very efficient motorboat. You'd certainly be able to get around 2nm/litre, cruising at around 7 knots on one engine.

You'd have to go a long way before the rig and sails started paying for themselves.
I did give this idea some consideration. Problem is, it doesnt quite work this way. It comes down to you either build a sail boat or a motor boat, 2 completely different hull forms with different associated design features. You start to get into trouble when trying to make one do the work of the other.

Problem is, no one designs a motor boat that will only go 7 knots, they all design them to go 25kn plus. For a while I was annoyed I hadnt waited a little longer to start because not long after I had Schionning came out with their outboard powered cruising cats but even these are designed to motor at 20 knots so require big outboards.....I would be happy to build a 7knt cruiser that only needs a sub $15k motor pair but try pricing even a 100hp outboard. There is half a mast right there.

But with the hull form we have, sailing cat hulls, they dont handle too well when loaded with 1500kgs of fuel, or in other words a 3000kg payload. Suddenly you have overloaded the sail boat design waterline and things start to go wrong. Not so efficient motor boat then.

But yes I considered it for a while. Until I started to read about peak oil. If you think fuel is going to stay $2 a litre (thats what you pay for it when you have to fill at the marina now, and what happens if you need 1500 liters for a passage like say Galapagos to Marquiesas) you are in for a shock. Fuel will double again in price within the next 5 years IMO.

No, unfortunately for the foreseeable future I can see no other option but to continue down the path of sailing. Like I said, I dont derive any pleasure from it, its a means to an end. To get from one nice anchorage to another. I also want to a certain extent "drop out". Having to continually call in for fuel, without which I am stuck where I am, puts a cramp in that part of my plan. Not a killer blow but a cramp nonetheless.

I still have no great interest in squeezing out another half a knot by tweaking. If conditions dictate, I would be just as happy motoring at 5kn as sailing at 10. Its all relative. Mono cruisers on slower older full keelers are happy with 4 to 5 knots top speed. I will be happy with 6 to 8 and couldnt care less about going as fast as the conditions allow, speed does not thrill me nor does beating the other guy to the next mark. I just want to be safe, or as safe as can be but still enjoying the anchorages I wish to visit.

The only reason I am building wings is because the others are and it gives me access to the know how. But before I do I will be investigating round masts to see if I can put them on the boat cheaper than the current rig will cost. Then all of this talk is moot anyway.
mahnamahna
Posts: 580
Joined: Wed Aug 02, 2006 4:48 pm
Location: Gosford NSW

Re: BIPOLAR

Post by mahnamahna »

groper wrote:
I got the schionning study plans which show the main bulkhead we are talking about next to the masts at 3300mm from the bow - so its all good, cheers anyway.
Maybe that 3300mm is from the face of bulkhead "0" (In the actual build plans, all datum is taken from the front face of bulkhead "0" so bulkhead 2 for example is not a specific distance from bulkhead 1, it and all the others are measured from zero datum, the front face of bulkhead "0").

My mast post centre will be 4000mm from the tip of my bow at the deck. The tip of the bow at the deck is a subjective measure because some build the new fangly reverse bows, some build square bows and some slightly angled aft top to bottom bows. Mine are the latter, with the tip of the bows at the deck about 250mm forward of the bow at the waterline which in turn is about 250mm forward of bulkhead "0" then angling up so that my bow at deck is about 500mm forward of bulkhead "0".

The front face of the mast post exits the deck about 100mm aft of the bulkhead it is on and the post is 200mm diameter (so 100mm from outer edge to centre. Add that 200mm to the 500mm from bow tip to bulkhead "0" and you have 700mm, add to that the 3300mm from "0" bulkhead to bulkhead 3 and you have the 4000mm that mine is back from the bow.
michaelo
Posts: 51
Joined: Mon Jan 28, 2008 12:44 am
Location: Melbourne

Re: BIPOLAR

Post by michaelo »

Hi Groper
There are no mainsheet tracks, the mainsheet goes from the boom to a swivel fitting on the cockpit roof then down through the roof support to a winch on the cockpit coaming


Image
Smooth Cruiser
Posts: 583
Joined: Thu May 11, 2006 1:51 am
Location: Brisbane

Re: BIPOLAR

Post by Smooth Cruiser »

Good to see it working so well for you michaelo! There's always going to be teething issues with a relatively untried (at this scale) rig like this but it is great to see the performance figures and the potential - really makes one think!

mahnamahna - I bet you start tweaking when you are sailing along beside fellow cruisers and they start to creep ahead of you! And I would agree that having control of your mast rotation is necessary - the perforamcne gains will be significant but even ignoring this what you will find in a seaway is that as the boat rolls in the waves the masts will spin and pump uncontrollably if there is no rotation control, which will be annoying and will damage gear. In these conditions you need to be able to actively position and lock the mast. I would suggest you also need to be able to do this at anchor or in a marina.
Chrisg
Posts: 141
Joined: Wed Feb 17, 2010 6:55 am
Location: Country Victoria

Re: BIPOLAR

Post by Chrisg »

Hi Michaelo, I am building near Melbourne and would like to speak with you if thats OK. Would you mind getting touch via a PM please.
Chris & Michelle

Outback Dreamer - Sarah 23
http://www.outbackdreamer.com
mahnamahna
Posts: 580
Joined: Wed Aug 02, 2006 4:48 pm
Location: Gosford NSW

Re: BIPOLAR

Post by mahnamahna »

I may have found (well I didnt find it, but I now know about it) a solution to the wing mast depower problem discussed in this and other threads (remember the tweakers?).

http://www.sailmagazine.com/boats/have- ... mainstream

Rather than a wing mast that cannot be de-powered but must be feathered, a wing sail on a round rotating mast, can be reefed, does not power at anchor, the rig itself is probably much cheaper to build and the idea is gaining mainstream attention, so perhaps may mitigate re-sale value issues.

About the only thing I think that might be more expensive is the actual sails, double the sail cloth required. I will need to investigate if a bi rig version of this will work. But it looks promising.
Redreuben
Posts: 27
Joined: Sun Dec 18, 2011 11:19 am
Location: Fremantle W.A.

Re: BIPOLAR

Post by Redreuben »

Here is a simpler version/system that may be of interest.

http://www.advancedwingsystems.com
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