Proud Mary

 
gearbox
 
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gearbox
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08 June 2013 13:13
 

Here’s a video of Proud Mary butt steering.

http://youtu.be/eKuecjDqAL8

It’s a bit long and boring, but shows a few different boat reactions to more or less extreme steering.

At two instances, just before and just after the shunt, I’ve steered it almost “in irons”, and then beard off.
You can see it is very fast pointing up wind, and a bit less keen the other way. I think this is partly because the ama drags more when the weight is forwards, and even more if weight is forwards and to windward.

I’ve noticed it being easier and more effective with two persons aboard, as more weight can be more distributed or more concentrated in one side, and one person can stand up, witch makes movements and balancing the ama’s lift off the water easier, faster and more precise.

Also interesting is that i manage to shunt in any point of sail, and it always points upwind (quite abruptly in stronger winds) immediately after shunt is completed.

Generally I don’t need to change course as much and as quickly as in the video, so smaller adjustments work well.

It might not be all that good when compared to other proas, I haven’t seen any data or videos that can give me a point of comparison nor have I sailed (or seen!) any other proa.

I have no doubt that any well studied and applied board steering will be more effective, but I often sail in 4 or 5 inches of water, so I’m happy with it!

Cheers

 
gearbox
 
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gearbox
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08 June 2013 13:15
 
TINK - 04 June 2013 01:55 PM
gearbox - 04 June 2013 12:50 PM

The rocker probably makes it easier to steer with paddle. I noticed it was very hard to steer proud mary with the steering oars, or a rudder (unless you moved your butt as well!). That’s how I ended up with nothing but butt steering!

This is very interesting, I noticed on your latest post (the maiden voyage one) you used a paddle. When you save very hard steer could you describe the difficulties you experienced. Another forum has recently discussed paddle steering in detail. I think they identified three main types of steering
1) changing the amount of paddle in the water
2) twisting / rotating the axis if the paddle
3) rotating the paddle about a pivot point from side to side

Second minor point, have you tried adding draft marks on each stem to measure how much you are changing the trim. From what I can see is you butt steering is highly effective and seams to require very little movement which I see as an extremely positive thing. If you look at other butt steered proas ( eg http://youtu.be/CWF64ipSfhg) they look to need much more weight aft, I think this one has much more rocker.

Tink


My experiences with searing oars and rudders where cut short at the point I realized that I could butt steer better than with any of the solutions I tried before.
Steering oars where very handy when in risk of going aback, or after, as we could row it back.
The steering itself never worked very well, and we tried all the mentioned methods.
Rudders, I only made a set of them and not the best ones i think. They where not effective at all, altho it might have been more the rudder design and execution than anything else…
Things that I didn’t try, and am convinced that would work, are: Place them at the bows. I had them placed halfway between the platform and the bows, and, use the “front” one as a dagger dagger/lee board. Both this alternatives would rather complicate my pro, and be a constant worry in shallow waters.

Once I manage to measure my leeway, if I find it to be really bad,  I plan to add a swinging leeboard in the center of the vakka, but ignorance is blessed(!), and for now I’m happy with what I have, I can still make my way upwind…

 

 
gearbox
 
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gearbox
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08 June 2013 17:04
 
TINK - 04 June 2013 01:55 PM

Second minor point, have you tried adding draft marks on each stem to measure how much you are changing the trim.

It is fairly well visible in the video, but is a good idea, as might give a more precise indicator wile sailing, at least in calm sea. Next time proa comes home I’ll have one more task… maybe combined with a funky paint job!

Thanks TINK!

 
Luomanen
 
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Luomanen
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08 June 2013 19:54
 

I’ve only checked out this video one time, but its very impressive!

It looks like you’re not changing sail trim much as you change your angle to the wind, and yet its pretty much working.

Is that your experience?

Thanks for your contribution, Gearbox.

Chris

 
gearbox
 
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gearbox
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08 June 2013 20:19
 
Luomanen - 08 June 2013 07:54 PM

I’ve only checked out this video one time, but its very impressive!

It looks like you’re not changing sail trim much as you change your angle to the wind, and yet its pretty much working.

Is that your experience?

Thanks for your contribution, Gearbox.

Chris

This was the end of a sailing afternoon, I just remembered you had asked for it when coming in… i was tired and wasn’t paying too much attention to the sail, but yes, just little adjustments and it works fine, but it keeps the power better when you trim it properly for the point of sail.

When sailing my old 31’ Te Wa, we mostly sailed standing up.  We’d be reaching along with the wind abeam and if I wanted to head upwind, I’d send someone up to sit near the bow.  If I wanted to bear away quickly we’d all head aft.  Sail trim is also part of it especially with the oceanic lateen rig.  Sheeting in causes you to bear away and easing the sheet will cause you to head up.  The only time this isn’t satisfactory is on a very broad reach where a slight course change could get you into a gybe.  I always had a steering oar and used it if I needed to go downwind.  The Gibbons rig I used later on a smaller proa didn’t have the same steering effect mainly because (I think) because of the shorter foot of the sail.

I’ve just read Gary’s post after, but I don’t think the sail trim affects this proa that much, witch agrees with his experience with the Gibbons rig. I’ve always adjusted it the other way around, as in a “normal” boat (sail out bear out, sail in point higher). Will test it further next time out.
I must add that I’m not an experienced sailor, so there might be lots of things I’m overlooking or completing missing!

Cheers

 
tdem
 
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tdem
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08 June 2013 21:10
 

Sheeting in should theoretically help you bear away, I think, because it means there is more force in front of the pivot point of the hull causing a turning moment.

Great video!

 
 
gearbox
 
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gearbox
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08 June 2013 21:27
 
tdem - 08 June 2013 09:10 PM

Sheeting in should theoretically help you bear away, I think, because it means there is more force in front of the pivot point of the hull causing a turning moment.

Great video!


It makes sense, I might be getting it all wrong… I usually work it out when i get in the boat! 😊
Thanks, glad you like the video!

 
Johannes
 
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Johannes
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09 June 2013 01:06
 

http://youtu.be/eKuecjDqAL8

It’s a bit long and boring, but shows a few different boat reactions to more or less extreme steering.

At two instances, just before and just after the shunt, I’ve steered it almost “in irons”, and then beard off.
You can see it is very fast pointing up wind, and a bit less keen the other way. I think this is partly because the ama drags more when the weight is forwards, and even more if weight is forwards and to windward.

I’ve noticed it being easier and more effective with two persons aboard, as more weight can be more distributed or more concentrated in one side, and one person can stand up, witch makes movements and balancing the ama’s lift off the water easier, faster and more precise.

Also interesting is that i manage to shunt in any point of sail, and it always points upwind (quite abruptly in stronger winds) immediately after shunt is completed.

Generally I don’t need to change course as much and as quickly as in the video, so smaller adjustments work well.

It might not be all that good when compared to other proas, I haven’t seen any data or videos that can give me a point of comparison nor have I sailed (or seen!) any other proa.

I have no doubt that any well studied and applied board steering will be more effective, but I often sail in 4 or 5 inches of water, so I’m happy with it!

I really love your video. I’m very impressed by the easy of steering with only weight-shift. It is easy to see the change in CLR when you move forward or backwards on your vaka.
The Gibbons and the crab claw are both very resistant to stalling and will keep driving the boat in a very broad spectrum of angles. I don’t think you need to worry about leeway. With a little more taut leeding edge on the sail it should be able to outpoint most monos. Especially in some stronger winds. I’m very very impressed by the absolut simplicity and efficiency of your boat!!! I think that is important and the right way to go. You have probably seen that I try to simplify my models and my design as much as possible.
What is not there - can not break or give any trouble, it does not cost anything and will never need any repair or rebuild.

Thanks for posting your videos! They are a great source of knowledge and inspiration.

Cheers,
Johannes

 
 
gearbox
 
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gearbox
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10 June 2013 00:03
 

Thanks Johannes, glad you like my proa. I do share your opinions on simplicity, and that’s why I find your threads very interesting.

With a little more taut leeding edge on the sail it should be able to outpoint most monos. Especially in some stronger winds.

I will open a new topic regarding the sail, once I do I’d love your ideas on it!

Cheers

 
gearbox
 
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gearbox
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21 June 2013 17:10
 

I finally have some GPS data! Comes up that I could have done it with my phone all the time… smart phone but not so smart owner!

I took Proud Mary out alone in +-9 knots wind, a fair current and waves.

Not all that great news, as expected. At best it seems to me it goes about 65degrees to the wind. :-(

From the compass it seems to point very high to the apparent wind, so it is a lot of leeway!
I think it does a little better when sailing with 2, as have an extra inch of draft, but probably not much on it.

At a practical level this doesn’t worry me much. Proud Mary is used as a fun beach proa, and that it delivers.
In one other way it is annoying to have numbers to put on performance… now I feel compelled to improve it! Oh well, more fun stuff awaits!

So, plans now are;
1- try a chine runner kind of option.
2- have a pivoted central leeboard if I really have to.

On the plus side, I did experiment a bit more with the sail steering, and am really impressed with the results.
My sail is now even worst and getting some strange shapes, and doesn’t seem to be performing that great, but still steers amazingly well and gave me 9.8kts max speed today,so cant complain!
This sail steering thing is specially very useful going downwind. I managed to easily keep a very broad reach just by controlling the sail, as it is effective but more subtle than but steering.

Here’s the GPS track of my longest out from today.

 

 
gearbox
 
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gearbox
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21 June 2013 17:17
 

Not great news from Mr GPS, but the 4inch draft is sooo nice…
Sailed all the way here today, after it stopped in the sand I jumped out with the sheet in my hand and it kept moving for another 20 yards or so!

 
Luomanen
 
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21 June 2013 17:56
 

65 degrees without a leeboard doesn’t sound so bad to me, Hugo.  You designed for minimum draft

It would be awfully convenient if a chine runner did the trick!  No extra draft. 

A pivoting Leeboard could provide more than just leeway prevention—swinging it fore and aft could give you another way to tune the CLR.  And you can always pivot it up and have your shallow draft again,

It does seem a shame to complicate things, doesn’t it?

Here’s a totally self interested suggestion.  Screw a piece of plywood that to the lee side that “looks” like 8 (ish?) more inches of rocker.  You loose your shallow draft temporarily.  But you test the theory behind SRIR!

Like I said—self interested.

Thanks for the report, Hugo.

Chris

 
gearbox
 
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gearbox
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21 June 2013 18:13
 

Chris,

65 degrees without a leeboard doesn’t sound so bad to me, Hugo. You designed for minimum draft

It’s true, and I was happy in my ignorance, but now I know and will have to improve it! (by the way, what is the normal/average pointing of a more traditional equivalent to PM?)

It would be awfully convenient if a chine runner did the trick!  No extra draft.

A pivoting Leeboard could provide more than just leeway prevention—swinging it fore and aft could give you another way to tune the CLR.  And you can always pivot it up and have your shallow draft again,

It does seem a shame to complicate things, doesn’t it?

Exactly my thoughts in all the points, it’s like you read my mind!

Here’s a totally self interested suggestion.  Screw a piece of plywood that to the lee side that “looks” like 8 (ish?) more inches of rocker.  You loose your shallow draft temporarily.  But you test the theory behind SRIR!

I love what you are doing with SRIR, and will help/test in any way I can! will try to do it early next week, as am wanting to bring it back for some improvement work soon.

Thanks Chris!

 

 
TINK
 
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TINK
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21 June 2013 22:23
 

Looks like good perforance to me, with such a simple workable proa it is a MAJOR acheivement.

Watching your brilliant but steering, see still below, you appear to have got about as far forward as you can both from a seating platform and bow down perspective. This suggests that you are needing to get the CLR quite far forward to balance the sails CE. From the video, and it may be just the camera angle, you could sheet in more. This however would bring the effective sail forces forward causing you to bear off until the forces are in balance again, not imprving anything. If you could get the CLR forward more or the sail back a little you may find you can get closer to the wind.

I am sure by now everyone has figured where I am going with this…...

Looking at your settup you could use a hook on leeboard which could be moved and placed forward of the mast. On the shunt it would have to be moved over to the new bow. A big hassle but good for a quick dirty experiment. Alternatively you could attach a strut between the two leeward ends the aka and mount a movable board on that. In that way the mast would not be in the way.

Yes I have arrived where you all suspected I might.

Armchair / YouTube theories aside I think there is a lot to think about here. How much is the upwind performance effected by leeway, limit of CLR movement, and the rig? Obviously all but to what proportion.

Wish you every luck in developing what in my mind is pretty close to the perfect sailing craft

Tink

 

 
 
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22 June 2013 05:07
 
gearbox - 21 June 2013 05:10 PM

Not all that great news, as expected. At best it seems to me it goes about 65degrees to the wind. :-(

So, plans now are;
1- try a chine runner kind of option.
2- have a pivoted central leeboard if I really have to.

For 2” of draft in a fairly new boat that is a marvelous track.

I’ll be interested in results of chine runner trials, also think there’s some goodness in better aero.

More work than a leeboard but a narrower hull would give you more lateral area.

Cheers,
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