Sailbydate

Coolboats to admire

Recommended Posts

1 hour ago, IStream said:

Last tango on the helipad?

Nah, my knees are shot. Yoga mats on the foredeck, maybe.

Share this post


Link to post
Share on other sites
On 3/28/2019 at 3:23 PM, olaf hart said:

Having that big pole so far up the bow isn’t a good thing either, you have to tack when motoring upwind in a blow, the bow keeps getting pushed downwind.

If we take Howard Chappell at his word the issue you describe becomes more pronounced with equal height masts.  The mizzen should be shorter than the main and be cut dead flat and used to provide directional stability. 

Making it worse every Freedom or Nunsuch (the Texas Ketches 33' Halsey Herreshoff design being the worst offender of bad sail cuts) I have ever been aboard had a silly amount of draft in the main. 

I love a Cat Ketch rig but it must be done correctly.  For what it is the Nunsuch is a great boat but not my idea of a Blue Water cruiser.

Share this post


Link to post
Share on other sites

Phil Bolger would agree and disagree. He would agree that the mizzen on a cat yawl is basically a steering and balance device and should be cut flat. He would say that his experience with cat rigs was that mainsails were often cut too flat, with the fullness too far aft.  Of course, I lot depends on how much the mast is going to bend.

Share this post


Link to post
Share on other sites

Here's a very different sort of cool boat - Killary Flyer. She was born as Noryema X (probably), aluminium hull, German Frers design c. 1975. Now used as an "adventure" boat based in the West of Ireland - playground is Greenland and so on. Still with the original coffee grinders and flush deck. Titchy helmsman's cockpit. It's wonderful that something so out and out racy of the time should have such a rich after life. And I'm glad they didn't waste money on a naval architect for the doghouse - and yes, that really is it, not a conning tower from the submarine parked behind it!   You can tell how windy Donegal is by the size of the blocks they tie the boats down to . . .

354492543_killaryflyer.thumb.JPG.6b7f93ce41705231affb63a9d2ca5b41.JPG

  • Like 2

Share this post


Link to post
Share on other sites

try and bump this thread ...saw this boat at Hobart just before wooden boat festival. 

went thru all the boats on catalogue and couldn't find it. Put it in a different thread on SA- no one knew what design/build

real nice looking boat - interestingly  rigging is synthetic (dyneema/spectra)

sorry, not best photo

baot hobart.jpg

  • Like 1

Share this post


Link to post
Share on other sites
On 5/13/2019 at 12:26 AM, Mr. Ed said:

Here's a very different sort of cool boat - Killary Flyer. She was born as Noryema X (probably), aluminium hull, German Frers design c. 1975. Now used as an "adventure" boat based in the West of Ireland - playground is Greenland and so on. Still with the original coffee grinders and flush deck. Titchy helmsman's cockpit. It's wonderful that something so out and out racy of the time should have such a rich after life. And I'm glad they didn't waste money on a naval architect for the doghouse - and yes, that really is it, not a conning tower from the submarine parked behind it!   You can tell how windy Donegal is by the size of the blocks they tie the boats down to . . .

354492543_killaryflyer.thumb.JPG.6b7f93ce41705231affb63a9d2ca5b41.JPG

Looks like a worthy cross-post to the dodgers forum.

- Stumbling

Share this post


Link to post
Share on other sites
On 5/22/2019 at 9:24 AM, Norm said:

try and bump this thread ...saw this boat at Hobart just before wooden boat festival. 

went thru all the boats on catalogue and couldn't find it. Put it in a different thread on SA- no one knew what design/build

real nice looking boat - interestingly  rigging is synthetic (dyneema/spectra)

sorry, not best photo

baot hobart.jpg

I don't recall the specifics of the boat, but 3, maybe 5 years ago at the Wooden Boat Festival sail past she fouled her rig in the bowsprit of a bigger boat (if memory serves), and snapped her rig in two. It took several years to repair. There may even be footage of the incident somewhere.

Share this post


Link to post
Share on other sites

Thanks All@

maybe explains why all the rigging rig looked very neat - seems quite a tall mast for a boat its age

 

 

Share this post


Link to post
Share on other sites

Fishing boats in the harbor in Rotterdam.  Check out the windlass on Risico.  UNADJUSTEDNONRAW_thumb_9cd.thumb.jpg.e3ce04b46d06017ce5d0d0eed72dbff5.jpg

UNADJUSTEDNONRAW_thumb_9c7.jpg

  • Like 2

Share this post


Link to post
Share on other sites

The Netherlands are full of these traditional vessels - both of these are cargo ships by the way.

The second one, with the leeboards is a skutsje. During the summer they are raced fanatically in their native Friesland.

Share this post


Link to post
Share on other sites

I can't get the photos to transfer but this link shows the 1950 Barton Broad reggata with the Norfolk Wherries racing. Sadly there is only half a dozen left now, they were originally the Norfolk equivalent of those previously shown dutch barges, that is Inland waterway cargo boats.

The Wherries Albion, Hathor, and Ardea mentioned in the text are three of the survivors.

http://www.broadlandmemories.co.uk/1950sgallerypage4.html

 

Share this post


Link to post
Share on other sites
1 hour ago, The Q said:

I can't get the photos to transfer but this link shows the 1950 Barton Broad reggata with the Norfolk Wherries racing. Sadly there is only half a dozen left now, they were originally the Norfolk equivalent of those previously shown dutch barges, that is Inland waterway cargo boats.

The Wherries Albion, Hathor, and Ardea mentioned in the text are three of the survivors.

http://www.broadlandmemories.co.uk/1950sgallerypage4.html

Chrome 'More tools | Developer tools | Sources':

devtools.thumb.jpg.929d886b0a01f29099216c5de403cb92.jpg

http://www.broadlandmemories.co.uk/images/gallery/1950s/hopthrow52_dragon_barton01.jpg

hopthrow52_dragon_barton01.jpg

http://www.broadlandmemories.co.uk/images/gallery/1950s/hopthrow52_dragonburgh.jpg

hopthrow52_dragonburgh.jpg

  • Like 1

Share this post


Link to post
Share on other sites

There is a video or 2 of them sailing on the Norfolk Broads. They are beautiful and our American catboats take more than a few attributes from them.

Share this post


Link to post
Share on other sites
On 5/22/2019 at 9:51 AM, stumblingthunder said:

Looks like a worthy cross-post to the dodgers forum.

Thanks for pointing that out. Looked like a large gas oven/grill to me. 

Share this post


Link to post
Share on other sites
2 hours ago, alphafb552 said:

The Netherlands are full of these traditional vessels - both of these are cargo ships by the way.

The second one, with the leeboards is a skutsje. During the summer they are raced fanatically in their native Friesland.

Thanks for the clarification, I'd seen paintings at the Rijksmuseum of similar vessels unloading their catch on the beach so I assumed.  Would love to see them underway, maybe next time.

Share this post


Link to post
Share on other sites
22 minutes ago, woahboy said:

Thanks for pointing that out. Looked like a large gas oven/grill to me. 

Or an unfaired submarine sail:

B-39Sub.jpg

Was going to say conning tower, but that actually refers to a smaller pressure vessel within the submarine sail so the periscopes could be shorter.

- Stumbling

  • Like 1

Share this post


Link to post
Share on other sites
52 minutes ago, stumblingthunder said:

Or an unfaired submarine sail:

B-39Sub.jpg

Was going to say conning tower, but that actually refers to a smaller pressure vessel within the submarine sail so the periscopes could be shorter.

- Stumbling

^^^That thing could go in the Zombie Fleet thread. Don't they ever clean those boats?

Share this post


Link to post
Share on other sites

I don't know anything about this boat except you can see in the picture. She was getting a thorough wash-down from the two guys you can see near the bow.

Jules.jpg

Share this post


Link to post
Share on other sites
4 hours ago, SemiSalt said:

I don't know anything about this boat except you can see in the picture. She was getting a thorough wash-down from the two guys you can see near the bow.

Jules.jpg

Looks like a Baltic 47 or 52.  Not sure which.  One of my favs.

Share this post


Link to post
Share on other sites

61183163_2232209083566631_47237068701103

That's a really Admirable gaff boom, at least while in use. The matching curve on the mizzen is cool too. And the way the rudder wraps around the transom.

If someone asked me to take that main sail down I think they'd just get a blank look.

  • Like 1

Share this post


Link to post
Share on other sites
On 5/24/2019 at 12:13 PM, luminary said:

Cool - it's got windows!

How else do they see where they're going?

 

Share this post


Link to post
Share on other sites
10 hours ago, Bob Perry said:

"And the way the rudder wraps around the transom."

Interesting. I see no transom.

Picky. Say something nice! I.T, say sorry. 

It’s a pretty boat. I’d love to see one. 

  • Like 1

Share this post


Link to post
Share on other sites
On 5/26/2019 at 9:45 AM, Bob Perry said:

"And the way the rudder wraps around the transom."

Interesting. I see no transom.

If you were wearing his glasses, you could see it clearly.

Maybe even two or three transoms

FB- Doug

Share this post


Link to post
Share on other sites

I like the gaff rig - mizzen seems small - is it still effective ?

With soft boom  - no out haul - flatten sail with downhaul and then reef? 

 

 

Share this post


Link to post
Share on other sites
On 5/26/2019 at 2:15 AM, Importunate Tom said:

61183163_2232209083566631_47237068701103

That's a really Admirable gaff boom, at least while in use. The matching curve on the mizzen is cool too. And the way the rudder wraps around the transom.

If someone asked me to take that main sail down I think they'd just get a blank look.

Pretty boat. What is it?

Looks a bit like Nigel Irens’ Romilly

Share this post


Link to post
Share on other sites
13 hours ago, valcour said:

Pretty boat. What is it?

Looks a bit like Nigel Irens’ Romilly

I've forgotten already. Something I saw on Facebook.

I'll go figure it out if you tell me how to get that main down.

On 5/26/2019 at 7:52 PM, Mr. Ed said:
On 5/26/2019 at 9:45 AM, Bob Perry said:

"And the way the rudder wraps around the transom."

Interesting. I see no transom.

Picky. Say something nice! I.T, say sorry. 

I can be picky. It's the flat part at the very back end of the boat. It looks like it's only an inch or so wide. I really shouldn't have to teach an eminent designer these things.

Share this post


Link to post
Share on other sites
3 hours ago, Importunate Tom said:

I've forgotten already. Something I saw on Facebook.

I'll go figure it out if you tell me how to get that main down.

I can be picky. It's the flat part at the very back end of the boat. It looks like it's only an inch or so wide. I really shouldn't have to teach an eminent designer these things.

Tom, getting the main down isn’t a problem.  Lower away.  (But that yard will extend aft at least as far as the transom, er, boomkin.)

The rudder looks like it would be appropriate for a double ender. A close look also reveals a sternpost.   And... you can see that there’s a bulwark that ends aft just short of the sternpost. She’s not a Romilly even tho a first glance evokes that thought.  

Share this post


Link to post
Share on other sites
4 hours ago, Veeger said:

Tom, getting the main down isn’t a problem.  Lower away.  (But that yard will extend aft at least as far as the transom, er, boomkin.)

The main looks to me like it's attached to that yard with a bolt rope. So now I'm done lowering it and the top of the main is extending off the stern along with the end of the yard?

Share this post


Link to post
Share on other sites

I believe Paul Fisher (of Selway Fisher) has designed a couple boats inspired by the Irens designs. Might be one of them.

Share this post


Link to post
Share on other sites

It has the full length battens and no boom of the Romilly, but the Romilly is a lug, not this single halyard gaff rig (the rig has a name I know, but I've forgotten).

 

E

Share this post


Link to post
Share on other sites
57 minutes ago, Mr. Ed said:

It has the full length battens and no boom of the Romilly, but the Romilly is a lug, not this single halyard gaff rig (the rig has a name I know, but I've forgotten).

 

E

The butt of the gaff is saddled to the mast, I think that's a gunter.

FB- Doug

Share this post


Link to post
Share on other sites
10 minutes ago, Steam Flyer said:

The butt of the gaff is saddled to the mast, I think that's a gunter.

FB- Doug

Does that mean it's fixed and doesn't slide down?

If so, that makes me wonder who climbs up there to thread the bolt rope?

It's a cool boat with a simple rig that I just can't figure out.

Share this post


Link to post
Share on other sites

The throat does slide down even though it doesn't look so - the one halyard pulls up the throat and the peak. I think SF is right (but maybe for the wrong reason) for the peak goes block to block, which is what I think makes it a gunter - conventional gaff rig boats often have saddles instead of jaws.

 

 

Share this post


Link to post
Share on other sites

I was worried about the helmsman's head.  Maybe isometric neck exercise?

Pretty boat though, and I really admire the mainsail shape.

Share this post


Link to post
Share on other sites
3 hours ago, Mr. Ed said:

The throat does slide down even though it doesn't look so - the one halyard pulls up the throat and the peak. I think SF is right (but maybe for the wrong reason) for the peak goes block to block, which is what I think makes it a gunter - conventional gaff rig boats often have saddles instead of jaws.

 

 

Right

The gunter has a single halyard and the yard/gaff/upper spar is set almost vertical. Some gaff mains are very high peaked but still have two halyards. One exception is the Dutch gaff which is short and curved.

FB- Doug

Share this post


Link to post
Share on other sites
19 minutes ago, Mr. Ed said:

Can’t we have a row about something? The internet wasn’t made for agreeing. 

Yes it was.

  • Like 1

Share this post


Link to post
Share on other sites
5 hours ago, Importunate Tom said:

"a simple rig that I just can't figure out."

Isn't this an oxymoron? They are rather rare on this forum.

BTW, I love the boat. Tom, tell us where you found it. It's quite paintable!

Share this post


Link to post
Share on other sites
1 hour ago, Ishmael said:
1 hour ago, Mr. Ed said:

Can’t we have a row about something? The internet wasn’t made for agreeing. 

Yes it was.

You're both full of shit

FB- Doug

Share this post


Link to post
Share on other sites
On 5/26/2019 at 10:15 AM, Importunate Tom said:

61183163_2232209083566631_47237068701103

That's a really Admirable gaff boom, at least while in use. The matching curve on the mizzen is cool too. And the way the rudder wraps around the transom.

If someone asked me to take that main sail down I think they'd just get a blank look.

Is that mizzen off-center?

Share this post


Link to post
Share on other sites
On ‎5‎/‎24‎/‎2019 at 10:41 PM, alphafb552 said:

The Netherlands are full of these traditional vessels - both of these are cargo ships by the way.

The second one, with the leeboards is a skutsje. During the summer they are raced fanatically in their native Friesland.

In 1977 I was living in Holland, went to Friesland for the skutjesilen championship. The sheer size of the booms and gaffs and mainsails was scary. The crews push them to the limit, and those big fat leeboarded hulls get up to some unlikely speeds.

Share this post


Link to post
Share on other sites
On 5/29/2019 at 2:18 AM, Importunate Tom said:

The main looks to me like it's attached to that yard with a bolt rope. So now I'm done lowering it and the top of the main is extending off the stern along with the end of the yard?

Yeah, that's what it looks like to me.  So much for a shorter loa for a slip...  I've seen these type of deals and having that yard limited to only one side or whichever side of the mizzen that it comes down on seems... well.... un-handy.

Share this post


Link to post
Share on other sites
On 5/26/2019 at 9:45 AM, Bob Perry said:

Interesting. I see no transom.

As we now see clearly, there ain't no transom.

Share this post


Link to post
Share on other sites

An infinite number of transoms will describe an arc

  • Like 2

Share this post


Link to post
Share on other sites
On 5/30/2019 at 12:45 AM, MFH125 said:

Is that mizzen off-center?

Better the mizzen than the companionway.   Offset companionway invites death and destruction, as confirmed by numerous SA threads!

- Stumbling

  • Like 2

Share this post


Link to post
Share on other sites
On 5/31/2019 at 7:18 PM, Elegua said:

An infinite number of transoms will describe an arc

And the inverse is true, an arc will describe an infinite number of transoms!

- Stumbling

  • Like 2

Share this post


Link to post
Share on other sites
22 minutes ago, stumblingthunder said:
On 5/29/2019 at 5:45 PM, MFH125 said:

Is that mizzen off-center?

Better the mizzen than the companionway.   Offset companionway invites death and destruction, as confirmed by numerous SA threads!

 

 

Oh yes. Offset companionways are an instrument of the devil, with pedals. They cause a disturbance in The Force. Boats with an offset companionway can only be redeemed if they are built in pairs, and turned into catamarans (which are also instruments of the devil).

FB- Doug

  • Like 1

Share this post


Link to post
Share on other sites
7 hours ago, alphafb552 said:

Redeemed??? With TWO offset companionways?????

How is that even possible...

They cancel each other out. Or not, depending on the orientation. 

Share this post


Link to post
Share on other sites
34 minutes ago, Ishmael said:

They cancel each other out. Or not, depending on the orientation. 

I see them a bit like imaginary numbers. When squared they are negative, and when you get rid of one, take the square root, it’s still negative. Either way, you’re going down. 

  • Like 4

Share this post


Link to post
Share on other sites
11 hours ago, Steam Flyer said:

 

Oh yes. Offset companionways are an instrument of the devil, with pedals. They cause a disturbance in The Force. Boats with an offset companionway can only be redeemed if they are built in pairs, and turned into catamarans (which are also instruments of the devil).

FB- Doug

Popular in Australia with lots of production Northshore 33s built although a later version went to a central companionway. Cavalier 37s  also have offset companionways. Works well for their interior layouts but not pleasing to the eye  for many who consider symmetry an important factor in yacht aesthetics.

Share this post


Link to post
Share on other sites
2 hours ago, Elegua said:

I see them a bit like imaginary numbers. When squared they are negative, and when you get rid of one, take the square root, it’s still negative. Either way, you’re going down. 

THIS !

Share this post


Link to post
Share on other sites
7 hours ago, SPORTSCAR said:
18 hours ago, Steam Flyer said:

... offset companionway ...    ...    ...

Popular in Australia with lots of production Northshore 33s built although a later version went to a central companionway. Cavalier 37s  also have offset companionways. Works well for their interior layouts but not pleasing to the eye  for many who consider symmetry an important factor in yacht aesthetics.

Well right, it's just a running insider joke around here. I am not sure how it started but offset companionways are ugly, prone to leak, cause warm beer, etc etc.

 

9 hours ago, Elegua said:

I see them a bit like imaginary numbers. When squared they are negative, and when you get rid of one, take the square root, it’s still negative. Either way, you’re going down. 

Not only that, but it is impossible to properly make French Toast on a boat with an offset companionway

FB- Doug

  • Like 1

Share this post


Link to post
Share on other sites

There are some legitimate concerns with offset companionways, where they present potential vulnerability during a knockdown.

I seem to recall it was a factor in the rapid sinking of the Pride of Baltimore

Share this post


Link to post
Share on other sites
12 hours ago, SPORTSCAR said:

Popular in Australia with lots of production Northshore 33s built although a later version went to a central companionway. Cavalier 37s  also have offset companionways. Works well for their interior layouts but not pleasing to the eye  for many who consider symmetry an important factor in yacht aesthetics.

Could we now call them "Asymmetric" companionways?

  • Like 3

Share this post


Link to post
Share on other sites
36 minutes ago, woahboy said:

Could we now call them "Asymmetric" companionways?

Mono-quantumametric gateway?  An unbalanced quantum relationship (sans-entanglement.)  Once you enter, you remain in a void you cannot escape, as the other end does not exist...

-Stumbling

 

  • Like 2

Share this post


Link to post
Share on other sites
7 hours ago, stumblingthunder said:
8 hours ago, woahboy said:

Could we now call them "Asymmetric" companionways?

Mono-quantumametric gateway?  An unbalanced quantum relationship (sans-entanglement.)  Once you enter, you remain in a void you cannot escape, as the other end does not exist...

That sounds worse than a Schrodinger companionway... or Klein bottle companionway, at least those don't leak

FB- Doug

 

  • Like 1

Share this post


Link to post
Share on other sites
2 hours ago, Steam Flyer said:

That sounds worse than a Schrodinger companionway... or Klein bottle companionway, at least those don't leak

FB- Doug

 

An Escher companionway would be a major obstacle. "I'm going downstairs, I'll drop you the chute."

  • Like 1

Share this post


Link to post
Share on other sites
34 minutes ago, Ishmael said:

An Escher companionway would be a major obstacle. "I'm going downstairs, I'll drop you the chute."

I have sailed with quite a few crew over my lifetime would would think that an Escher companionway and interior would make perfect sense...

Relativity-escher.jpg

(Hell, I would find it rather entertaining, myself!)

- Stumbling

Share this post


Link to post
Share on other sites
3 hours ago, Steam Flyer said:

That sounds worse than a Schrodinger companionway... or Klein bottle companionway, at least those don't leak

FB- Doug

 

Schrodinger companionway - its both offset and centered, you just don't know which it is until you try to use it?   Or is it that once you enter it, the rest of the crew on deck can assume you are both sleeping and awake (dead and alive,) but don't know until they go down below to check on you.   But then, the checking crew member now becomes both sleeping and awake and the rest of the crew on deck is now debating that both of you are both sleeping and awake below...  

Sounds like they spent a little too much time in a safety meeting before heading out!

- Stumbling

  • Like 1

Share this post


Link to post
Share on other sites
5 minutes ago, stumblingthunder said:

I have sailed with quite a few crew over my lifetime would would think that an Escher companionway and interior would make perfect sense...

Relativity-escher.jpg

(Hell, I would find it rather entertaining, myself!)

- Stumbling

I would like to be able to change out the masthead bulb by taking up a floorboard, but so far it's just been olfactory challenged water.

  • Like 1

Share this post


Link to post
Share on other sites
4 minutes ago, Ishmael said:

I would like to be able to change out the masthead bulb by taking up a floorboard, but so far it's just been olfactory challenged water.

Thats because you keep going to the wrong place, its in the right hand portion of the 2nd shelf in the medicine cabinet in the head!

- Stumbling

Share this post


Link to post
Share on other sites

The Kronecker Delta companionway is there when you need it, and not when you don't.  Or vice versa,

  • Like 2

Share this post


Link to post
Share on other sites
8 hours ago, stumblingthunder said:

I have sailed with quite a few crew over my lifetime would would think that an Escher companionway and interior would make perfect sense...

Relativity-escher.jpg

(Hell, I would find it rather entertaining, myself!)

- Stumbling

image.png.9bfb06e8aefc7d733cc6d4d36113f9be.png

  • Like 2

Share this post


Link to post
Share on other sites

The Dunning-Kruger companionway is so offset that it doesn't know how offset it is.

  • Like 3

Share this post


Link to post
Share on other sites
33 minutes ago, monsoon said:

The Dunning-Kruger companionway is so offset that it doesn't know how offset it is.

And it's unfortunately all the rage these days.

Share this post


Link to post
Share on other sites
40 minutes ago, monsoon said:

The Dunning-Kruger companionway is so offset that it doesn't know how offset it is.

I know a few boats that have raced like that their whole existence...

- Stumbling

Share this post


Link to post
Share on other sites
1 hour ago, SemiSalt said:

The Kronecker Delta companionway is there when you need it, and not when you don't.  Or vice versa,

Depends on whether the orientation is synchronous or 180o out of phase!

- Stumbling

Share this post


Link to post
Share on other sites
12 hours ago, Steam Flyer said:

That sounds worse than a Schrodinger companionway... or Klein bottle companionway, at least those don't leak

FB- Doug

 

Surely a Schrodinger companionway would only work on a Cat?

  • Like 4

Share this post


Link to post
Share on other sites
10 hours ago, stumblingthunder said:

I have sailed with quite a few crew over my lifetime would would think that an Escher companionway and interior would make perfect sense...

Relativity-escher.jpg

(Hell, I would find it rather entertaining, myself!)

- Stumbling

I sailed with Esher's grandson. There was a distorted sense of reality on that whole delivery trip. It extended well beyond the bounds of the boat too. I would go off watch and get up 4 hours later and we would be 20 miles further away from our goal than when I went to sleep! There may have been drugs involved...

  • Like 2

Share this post


Link to post
Share on other sites
3 hours ago, SemiSalt said:

The Kronecker Delta companionway is there when you need it, and not when you don't.  Or vice versa,

In mathematics, the Kronecker delta (named after Leopold Kronecker) is a function of two variables, usually just non-negative integers. The function is 1 if the variables are equal, and 0 otherwise:

 
 
δ i j = { 0 if  i ≠ j , 1 if  i = j . {\displaystyle \delta _{ij}={\begin{cases}0&{\text{if }}i\neq j,\\1&{\text{if }}i=j.\end{cases}}} \delta _{{ij}}={\begin{cases}0&{\text{if }}i\neq j,\\1&{\text{if }}i=j.\end{cases}}

where the Kronecker delta δij is a piecewise function of variables i and j. For example, δ1 2 = 0, whereas δ3 3 = 1.

The Kronecker delta appears naturally in many areas of mathematics, physics and engineering, as a means of compactly expressing its definition above.

In linear algebra, the n × n identity matrix I has entries equal to the Kronecker delta:

I i j = δ i j {\displaystyle I_{ij}=\delta _{ij}} {\displaystyle I_{ij}=\delta _{ij}}

where i and j take the values 1, 2, ..., n, and the inner product of vectors can be written as

a ⋅ b = ∑ i , j = 1 n a i δ i j b j . {\displaystyle \mathbf {a} \cdot \mathbf {b} =\sum _{i,j=1}^{n}a_{i}\delta _{ij}b_{j}.} {\displaystyle \mathbf {a} \cdot \mathbf {b} =\sum _{i,j=1}^{n}a_{i}\delta _{ij}b_{j}.}

The restriction to positive integers is common, but there is no reason it cannot have negative integers as well as positive, or any discrete rational numbers. If i and j above take rational values, then for example

δ ( − 1 ) ( − 3 ) = 0 δ ( − 2 ) ( − 2 ) = 1 δ ( 1 2 ) ( − 3 2 ) = 0 δ ( 5 3 ) ( 5 3 ) = 1. {\displaystyle {\begin{aligned}\delta _{(-1)(-3)}&=0&\qquad \delta _{(-2)(-2)}&=1\\\delta _{\left({\frac {1}{2}}\right)\left(-{\frac {3}{2}}\right)}&=0&\qquad \delta _{\left({\frac {5}{3}}\right)\left({\frac {5}{3}}\right)}&=1.\end{aligned}}} {\displaystyle {\begin{aligned}\delta _{(-1)(-3)}&=0&\qquad \delta _{(-2)(-2)}&=1\\\delta _{\left({\frac {1}{2}}\right)\left(-{\frac {3}{2}}\right)}&=0&\qquad \delta _{\left({\frac {5}{3}}\right)\left({\frac {5}{3}}\right)}&=1.\end{aligned}}}
 
 
 
 
I knew that.
 

Share this post


Link to post
Share on other sites
2 hours ago, monsoon said:

The Dunning-Kruger companionway is so offset that it doesn't know how offset it is.

They seem to really like them in Florida.

Share this post


Link to post
Share on other sites
1 hour ago, SloopJonB said:

In mathematics, the Kronecker delta (named after Leopold Kronecker) is a function of two variables, usually just non-negative integers. The function is 1 if the variables are equal, and 0 otherwise:

 
 
δ i j = { 0 if  i ≠ j , 1 if  i = j . {\displaystyle \delta _{ij}={\begin{cases}0&{\text{if }}i\neq j,\\1&{\text{if }}i=j.\end{cases}}} \delta _{{ij}}={\begin{cases}0&{\text{if }}i\neq j,\\1&{\text{if }}i=j.\end{cases}}

where the Kronecker delta δij is a piecewise function of variables i and j. For example, δ1 2 = 0, whereas δ3 3 = 1.

The Kronecker delta appears naturally in many areas of mathematics, physics and engineering, as a means of compactly expressing its definition above.

In linear algebra, the n × n identity matrix I has entries equal to the Kronecker delta:

I i j = δ i j {\displaystyle I_{ij}=\delta _{ij}} {\displaystyle I_{ij}=\delta _{ij}}

where i and j take the values 1, 2, ..., n, and the inner product of vectors can be written as

a ⋅ b = ∑ i , j = 1 n a i δ i j b j . {\displaystyle \mathbf {a} \cdot \mathbf {b} =\sum _{i,j=1}^{n}a_{i}\delta _{ij}b_{j}.} {\displaystyle \mathbf {a} \cdot \mathbf {b} =\sum _{i,j=1}^{n}a_{i}\delta _{ij}b_{j}.}

The restriction to positive integers is common, but there is no reason it cannot have negative integers as well as positive, or any discrete rational numbers. If i and j above take rational values, then for example

δ ( − 1 ) ( − 3 ) = 0 δ ( − 2 ) ( − 2 ) = 1 δ ( 1 2 ) ( − 3 2 ) = 0 δ ( 5 3 ) ( 5 3 ) = 1. {\displaystyle {\begin{aligned}\delta _{(-1)(-3)}&=0&\qquad \delta _{(-2)(-2)}&=1\\\delta _{\left({\frac {1}{2}}\right)\left(-{\frac {3}{2}}\right)}&=0&\qquad \delta _{\left({\frac {5}{3}}\right)\left({\frac {5}{3}}\right)}&=1.\end{aligned}}} {\displaystyle {\begin{aligned}\delta _{(-1)(-3)}&=0&\qquad \delta _{(-2)(-2)}&=1\\\delta _{\left({\frac {1}{2}}\right)\left(-{\frac {3}{2}}\right)}&=0&\qquad \delta _{\left({\frac {5}{3}}\right)\left({\frac {5}{3}}\right)}&=1.\end{aligned}}}
 
 
 
 
I knew that.
 

Now my head hurts. Thanks SJB

Share this post


Link to post
Share on other sites

Aww man.  I am still falling asleep during math class.  :D

Share this post


Link to post
Share on other sites

can we get back to boats.....sails are under load and seems overpowered in light breeze

foto04.jpg

Share this post


Link to post
Share on other sites

Lots of wind and flat water.

Purrfeck.

  • Like 1

Share this post


Link to post
Share on other sites

I know it’s a trimaran, but I had a great ride on the trimaran Skateaway yesterday and enjoyed sailing a beam reach at 19-21 knots sustained in a 15 knot southerly. 

C0C45CAD-45E8-40C4-884E-875365712069.jpeg

939EA3B6-5AE3-457E-BDC8-DDFD686C9DDB.png

A319CC05-6A3A-49B5-AF3D-1DACB6E6C382.jpeg

  • Like 2

Share this post


Link to post
Share on other sites

It's a trimaran, but it is still the sum of two offset companionways. 

  • Like 2

Share this post


Link to post
Share on other sites
1 hour ago, Sail4beer said:

I know it’s a trimaran, but I had a great ride on the trimaran Skateaway yesterday and enjoyed sailing a beam reach at 19-21 knots sustained in a 15 knot southerly. 

C0C45CAD-45E8-40C4-884E-875365712069.jpeg

939EA3B6-5AE3-457E-BDC8-DDFD686C9DDB.png