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Keel footprint.

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Created by NowandZen > 9 months ago, 22 Sep 2020
stray
SA, 316 posts
26 Sep 2020 10:29PM
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NowandZen said..
G'day salty sea dogs!

You might look at the title of this thread and think WTF?
Let me explain and ask what maybe a stoopid question.

Let's say I was looking to buy a 40ft+ yacht and one of the items on the wish list was that it had to have a deep draft - say at least 2.0m+, is it possible to make a deeper draft vessel out of a shallow draft??
I'm obviously talking about bolt on's and I prefer encapsulated keels, but the choices of yachts in that area seem limited.

I don't really wan't to discuss the pro's and con's of deeper keels vs shallow - it's been done before.

Cheers!!


Cant you just buy a boat with a deep keel.
just a thought.

Donk107
TAS, 2446 posts
27 Sep 2020 2:31PM
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This is my mates Farr 30 which is on the slip at the moment compared to my Sailmaster

The Farr points pretty well but is a bugger to work on as everything is above head height

Regards Don




NowandZen
WA, 384 posts
27 Sep 2020 5:45PM
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stray said..


NowandZen said..
G'day salty sea dogs!

You might look at the title of this thread and think WTF?
Let me explain and ask what maybe a stoopid question.

Let's say I was looking to buy a 40ft+ yacht and one of the items on the wish list was that it had to have a deep draft - say at least 2.0m+, is it possible to make a deeper draft vessel out of a shallow draft??
I'm obviously talking about bolt on's and I prefer encapsulated keels, but the choices of yachts in that area seem limited.

I don't really wan't to discuss the pro's and con's of deeper keels vs shallow - it's been done before.

Cheers!!




Cant you just buy a boat with a deep keel.
just a thought.



Great idea!! .......If I could find one that has all the features I'm looking for that is.
I see so many that look like good yachts in every other aspect, but have a shallow draft keel.
That's why I started the thread - to see what people thought about the viability of extending or swapping out a keel on a yacht that otherwise appeared suitable.

Yara
NSW, 1250 posts
28 Sep 2020 1:00PM
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Thing is, you want internal ballast integral keel. Me too, but that precludes a high aspect ratio (tall and skinny) keel, due to the difficulties of fabrication, and high stresses at the keel/hull joint. Life and boats are a compromise....

One compromise could be a fairly deep integral stub with a bolt-on lead lower section. Use bronze bolts, and IMHO it is a good as an integral keel.
SS30 Yankee comes to mind.

lydia
1659 posts
28 Sep 2020 3:48PM
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Yara said..
Thing is, you want internal ballast integral keel. Me too, but that precludes a high aspect ratio (tall and skinny) keel, due to the difficulties of fabrication, and high stresses at the keel/hull joint. Life and boats are a compromise....

One compromise could be a fairly deep integral stub with a bolt-on lead lower section. Use bronze bolts, and IMHO it is a good as an integral keel.
SS30 Yankee comes to mind.


Problem with big stubs is that only one side is in tension.
You get the Mutiny 28 problem.

lydia
1659 posts
28 Sep 2020 3:49PM
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Donk107 said..
This is my mates Farr 30 which is on the slip at the moment compared to my Sailmaster

The Farr points pretty well but is a bugger to work on as everything is above head height

Regards Don





Pop quiz, pick the most sea worthy boat.

Donk107
TAS, 2446 posts
28 Sep 2020 6:21PM
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lydia said..


Donk107 said..
This is my mates Farr 30 which is on the slip at the moment compared to my Sailmaster

The Farr points pretty well but is a bugger to work on as everything is above head height

Regards Don






Pop quiz, pick the most sea worthy boat.





Hi Lydia

I would like to think the Sailmaster but i suspect it might be the Farr

Happy to be told I am wrong though

Regards Don

DrogueOne
VIC, 197 posts
28 Sep 2020 6:59PM
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One thing I found sailing on a Mt Gay 30 is that the groove is very narrow, With a high performance slender foil like that Farr/Mumm 30 you really have to be focusing to keep the boat moving well. Mess up a tack , let your attention wander and you are stalling it out, goodbye boatspeed hello leeway.

So NowAndZen, If a boat has almost all the features you find desirable except a deep keel, what is it about the lack of deep keel that makes you continue looking? Are you looking for more righting moment/better stability curve? Better windward performance? some other characteristic? It's kind of odd that there isn't something in the corner of the design box that meets your requirements. Pushing into the corners doesn't come free, you are going to get some other compromise that you will have to live with - like the easily stalled foil.

r13
NSW, 1427 posts
28 Sep 2020 7:02PM
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Believe Lydia would suggest that your's is the more sea worthy boat of the 2 Don - it will have a lot more comfortable motion. Obviously won't be nearly as fast as the Farr 30 but you'll still have your teeth in after a day's battle against a 30kt breeze upwind.

Yara
NSW, 1250 posts
28 Sep 2020 8:22PM
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lydia said..

Yara said..
Thing is, you want internal ballast integral keel. Me too, but that precludes a high aspect ratio (tall and skinny) keel, due to the difficulties of fabrication, and high stresses at the keel/hull joint. Life and boats are a compromise....

One compromise could be a fairly deep integral stub with a bolt-on lead lower section. Use bronze bolts, and IMHO it is a good as an integral keel.
SS30 Yankee comes to mind.



Problem with big stubs is that only one side is in tension.
You get the Mutiny 28 problem.


What is the Mutiny 28 problem? Most structures have one side in tension and the other in compression at some load condition?

lydia
1659 posts
29 Sep 2020 5:25AM
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It is a loaded question!

Yara
NSW, 1250 posts
29 Sep 2020 11:39AM
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lydia said..
It is a loaded question!


I once had a boss who told me there is no such thing as an embarrassing question, just an embarrassing answer.
Starting with IMHO or "alleged" might get you off the hook.

lydia
1659 posts
29 Sep 2020 10:22AM
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Yara said..

lydia said..
It is a loaded question!



I once had a boss who told me there is no such thing as an embarrassing question, just an embarrassing answer.
Starting with IMHO or "alleged" might get you off the hook.


As I remember, the keel stub and floor was quite flexible.

lydia
1659 posts
29 Sep 2020 10:26AM
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lydia said..

Donk107 said..
This is my mates Farr 30 which is on the slip at the moment compared to my Sailmaster

The Farr points pretty well but is a bugger to work on as everything is above head height

Regards Don





Pop quiz, pick the most sea worthy boat.


Depends on what you call sea worthy.
The Farr kills it on resistance to capsize and engineering.
but all 30 footers feel very small in a 6m sea.

NowandZen
WA, 384 posts
30 Sep 2020 4:34PM
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Thanks for all the comments.



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"Keel footprint." started by NowandZen