Keel of Adelie 16

Sail Boats 15' and up. Please include the boat type in your question.
terrulian
* Bateau Builder *
* Bateau Builder *
Posts: 2084
Joined: Sat Dec 07, 2013 11:29 am
Location: Marin County, CA
Contact:

Re: Keel of Adelie 16

Post by terrulian » Thu May 18, 2017 12:06 pm

jbro
I admire your careful thoughtfulness about this issue, good on you.

But perhaps you may want to consider that Jacques has many, many years of boat design behind him, and his designs have resulted in thousands of boats all across the globe. I mean no offense but it does seem peculiar to me to be trying to second-guess him. Perhaps you are a naval architect with equivalent experience; I don't mean to presume you have no knowledge of this area. But I would trust the design, build on, and you will have a fine, stable boat. It's a tiny boat anyway and isn't meant for open ocean voyages, which is the only place you'd run into conditions that may result in the boat becoming inverted. I sail a Catalina 22 nowadays, a bigger, heavier boat. I wouldn't consider taking it outside the Golden Gate although others have without incident on mild days.

Specifically, I think the 135 is the degrees off of vertical where the boat will right itself. I've been sailing a very long time and have never had a ballasted boat get close to 90 degrees. The boat will round up long before that. (If it didn't, there would be more serious problems with the design than how much ballast there is.) Otherwise, the only thing that could capsize the boat would be breaking waves.

I don't know about the design of the keel on the Adelie but having the centerboard at an angle increases its fore-and-aft profile, making it more weatherly--in other words, reducing leeway. Getting the keel further underwater provides more of a righting moment at the expense of upwind performance. I may be wrong about this as, unlike Jacques, I do not design boats. It is the same arrangement used in the Catalina 22 and other designs.


Tony
Image

Jaysen
* Bateau Builder *
* Bateau Builder *
Posts: 2337
Joined: Wed Aug 05, 2015 7:59 am
Location: St Helena Island, SC

Re: Keel of Adelie 16

Post by Jaysen » Thu May 18, 2017 12:16 pm

I would also think that keel depth, when adjustable, is generally minimized to reduce drag (optimize efficiency of hull). Maybe that's more of a "go fast" mentality though.

terrulian
* Bateau Builder *
* Bateau Builder *
Posts: 2084
Joined: Sat Dec 07, 2013 11:29 am
Location: Marin County, CA
Contact:

Re: Keel of Adelie 16

Post by terrulian » Thu May 18, 2017 1:00 pm

This is done downwind with a dinghy to reduce wetted surface.
Are you going to race this boat? How fast do want to go? Maybe an extra 1/10 of a knot?
Tony
Image

Salvatore
Frequent Poster
Frequent Poster
Posts: 194
Joined: Thu May 01, 2014 5:35 am
Location: Sydney, Australia

Re: Keel of Adelie 16

Post by Salvatore » Thu May 18, 2017 2:53 pm

G,day Jbro,

All sailing boats suffer from side ways drift, unless sailing with the wind. If you don't lower the CB all the way this will increase side ways drift and you will have to tack more often especially when the wind is on your beam. If the CB is half way up you will have less drag and a slight increase in speed, professional boat racing people carry this to a fine art the SB18 is better suited if you have a need for speed, if you are after a small pleasure cruiser the AD16 or the VG18 is best

I increased the weight of my CB with no trouble, but I installed a winch to lift it. I too considered a way of locking the CB at the full position but I never did it and now that I have sailed the boat for 3 seasons I am happy I didn't do it. This was my idea; I would make a acme screw that would push down on the CB so that it could not come back up, the screw would have a hex head so that I could use a removable winch handle. the skew bolt the the acme screw moves up and down on would be bolted to a metal plate that was attached to a few small screws in case I ran aground and the force of the sea bed would push up on the CB breaking the small screws loose.

Image
Regards Salvatore
Building Angelina
https://youtu.be/plQZZJgnWzk

User avatar
gonandkarl
* Bateau Builder *
* Bateau Builder *
Posts: 805
Joined: Sat Mar 16, 2013 10:25 am
Location: Wels,Austria,Europe

Re: Keel of Adelie 16

Post by gonandkarl » Thu May 18, 2017 6:00 pm

Hi Jbro,
Glad you got an answer from Salvatore who spoke of a fully down board. Yes it can be fully let down and it will not jam against the centre board case. It is important to position the pivot point correctly then the board is hanging down completely on its ss rod. To add an extra 60 pound lead pie is definitely not necessary except you want to sail even in a bad storm with the disadvantage you have to pull up a centreboard that weighs 180 pounds not to be done without a winch. I am sure Jacques the designer will tell you that his 3 designed lead weights in the centreboard are perfect for this type of boat. Before I started building my Adelie I always caught myself thinking far ahead and what will the behavior of my boat be in all possible situations or how often will I have a knock down or even worse a capsize. I got so paranoid that while waiting for the plywood and epoxy to arrive I bought 2 life jackets for my wife and myself. Luckily since I have started building the Adelie all thoughts of safety and worries about the hull and my future sailing on it have disappeared and changed to fun, excitement and pleasant anticipation to splash and use it with all design faults if there should be any and all my mistakes during the build just to enjoy to be with my boat and my granddaughter ( it will be her boat ) on the water away with a nonracer daysailer. Building an Adelie 16 will give you a lot of pleasure and will let you forget worries about is it the right design and other worries disappear on top of it.
Greetings from Karl
All pictures of Micro Petrel AD14 and FS13 :

http://gallery.bateau2.com/index.php?cat=87433

terrulian
* Bateau Builder *
* Bateau Builder *
Posts: 2084
Joined: Sat Dec 07, 2013 11:29 am
Location: Marin County, CA
Contact:

Re: Keel of Adelie 16

Post by terrulian » Thu May 18, 2017 7:44 pm

Karl: Wearing life vests is not paranoid. It is prudent boating.
When I learned to sail decades ago in SF bay, it was considered too wimpy to wear them and literally no manly sailor did. But one incident completely changed the culture and now it is required in every race on penalty of disqualification. What happened was there was a race along the City Front, a heavily trafficked area. There were lots of boats in the race, crewed by very experienced sailors. On one boat a wing collapsed and about four guys went into the water (this was 20 years ago so forgive me for not knowing the exact number). Despite all the boats out there attempting a rescue, by the time the last person was pulled out of the water--with full foulies but no life vest--he could not be revived. So much for manliness.
Don't go to sea without them.
Tony
Image

jbro5000
New Poster
New Poster
Posts: 7
Joined: Thu May 11, 2017 11:16 am
Location: Manila

Re: Keel of Adelie 16

Post by jbro5000 » Thu May 18, 2017 9:13 pm

Yes, thanks, I saw that.

There is no hurry for an answer but the issue remains:

Were the stability calculations done for an indicated design draft of 35" (ie with CB vertically down), or at what appears to be half way down,which looks like a draft of around 24" but could mean fully down from the drawings?

Kind regards

User avatar
gonandkarl
* Bateau Builder *
* Bateau Builder *
Posts: 805
Joined: Sat Mar 16, 2013 10:25 am
Location: Wels,Austria,Europe

Re: Keel of Adelie 16

Post by gonandkarl » Fri May 19, 2017 2:22 am

Hi,
I know it is not paranoid to wear a life jacket at all times but it is to buy it 3 years before you get the boat finished and also no chance of Noahs big flood nearby. I just wanted to emphasise that building a boat keeps you all the time in thought about the finished product of your own hands and lets you look all the time positively into the future. Good when you are as old as me because if I am realistic my future is limited because of backache, arthritis, wheather sensitivity, overweight and concentration gaps hopefully never long enough until a bus gets the better of me running me over.
For Jbro s info on my plan 264/8 Appendiges it was also not quite clear where the pivot point of the keel should be as well as the rounding off of the front of the keel not to let it jam against the top or the front of the trunk. I also missed a measurement of the centreboard which I got posted later by Jacques. With the help of a then excellent builder Bondo and Jacques advise I got it right and realised that boat building is not an accurate science and the shaping of the centreboard can be slightly adjusted to ones personal liking. The 135 degrees righting arm will be in half down position of the centreboard but I am sure Jacques will answer you much better than all of us when he is back end of June. We all are trying to convince you that you will be building a safe comfortable sailboat which has lots of fun in store once it is in the water. Start building the boat the plans for it exist since 2005 and you do not have to make them over again and do not get hung up on small details they can throw you back for days I know for sure. But all of us worldwide will help you to master any detail problem when you get to them.
Greetings from Karl
All pictures of Micro Petrel AD14 and FS13 :

http://gallery.bateau2.com/index.php?cat=87433

Salvatore
Frequent Poster
Frequent Poster
Posts: 194
Joined: Thu May 01, 2014 5:35 am
Location: Sydney, Australia

Re: Keel of Adelie 16

Post by Salvatore » Fri May 19, 2017 2:55 am

G,day Jbro,

I think now I understand your question :D the CB does not go all the way down as in "vertical" If it did it would rip itself out by the pin with the force of water pressure against it. It is only designed to go as far as when the front end of the CB touches the front end of the CB case. I cant recall how many degrees of movement that is but it is not a lot. The CB does not have a 90 degree swing on it. If you look at the crude drawing in the post I did this morning it is not much variance from that, when the CB is fully down it has like a v shape to it under the boat.
From the study notes: for AD16
Draft: 13" CB up
35" CB down
33 cm CB up
89 cm CB down

So from the waterline to the bottom of the Fixed part of the Keel with the CB inside it is 13" when the CB is let down all the way is another 22" that's it, Total 35" from the waterline.

Because the AD16 and AD14 have a solid/fixed keel even when the CB is all the way up it is working, it is not like other sail boats that have no fixed keel at all. I had a sail boat that had zero fixed keel on it, (just a smooth bottom) once and it would slide sideways without the CB down. The AD16 and AD14 will sail well in a light breeze with the CB up and will not slide side ways or should I say move to Lee :)
Regards Salvatore
Building Angelina
https://youtu.be/plQZZJgnWzk

terrulian
* Bateau Builder *
* Bateau Builder *
Posts: 2084
Joined: Sat Dec 07, 2013 11:29 am
Location: Marin County, CA
Contact:

Re: Keel of Adelie 16

Post by terrulian » Fri May 19, 2017 8:00 am

Yes, Salvatore, I was also confused about the "vertical" idea...and therefore may have given improper responses.:?
Still, I'm with Karl that it is best to trust the designer here. Boats that are dangerous--which are very rare, slow is much more common--quickly become known in the nautical world and go off the market. No naval architect or boat manufacturer wants to get that reputation.
Tony
Image

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest