Keel Inspection/Removal

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Keel Inspection/Removal

Postby Rakozy » Sat Oct 10, 2015 9:09 am

A few months ago, I purchased Roger Conrad's PDF book on all things DS II related. He goes into great detail on how to inspect and if necessary, remove the keel to swap out the ropes which control the up/down movement. (By the way, Roger Conrad's PDF download book is excellent and well worth purchasing a copy. You will learn a great deal about the inner workings of your DS II.)

I recently carefully "careened" my DS II in my driveway in order to remove 33 years of oxidation and check out the keel operation at the same time. I have attached a photo of what I found upon removing the keel from the bottom side of the boat.

Instead of finding the keel held in place by a stainless steel pivot bolt, there was no bolt to be found! In my boat, the keel pivots on a 4" round nylon core and held in place by two trapezoid shaped fiberglass blocks.. These blocks are held in place by the two stainless straps and bolted to the bottom of the hull.

At first I thought a former boat owner installed his own "midnight engineering" only to find that the two cores which support the weight of the keel are formed into the fiberglass bilge itself... so it had to be factory-built this way. I figured, "if it ain't broke, don't fix it". And I reinstalled it as it was.

I hope this attached photo is useful to someone else in understanding your DS II.

Any comments?
Attachments
DS2.1.jpg
DS2.1.jpg (32.94 KiB) Viewed 3567 times
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Re: Keel Inspection/Removal

Postby GreenLake » Sat Oct 10, 2015 9:11 am

Nice picture.

Small point: it's usually called a centerboard and not a keel.
~ green ~ lake ~ ~
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Re: Keel Inspection/Removal

Postby jeadstx » Sat Oct 10, 2015 11:47 am

Earlier DS II boats used a centerboard bolt (like my 1976 model), the later ones used the setup you have. Your setup is easier to work on than mine, since I have to reach in thru 4" inspection ports to get at the bolt. Unlike most boats, I also have the added pleasure of dealing with some really hard goop that was put over the bolts and will need to be ground off before I can remove the bolt.

John
1976 Day Sailer II, #8075 - Completed the 2011, 2012, and 2013 Texas 200
1952 Beetle Boat Swan Catboat
Early Rhodes 19
1973 Mariner 2+2, #2607 - Completed 2014, 2015 and 2016 Texas 200
1969 Day Sailer I, #3229
Fleet 135; Canyon Lake, Texas
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Re: Keel Inspection/Removal

Postby TIM WEBB » Sat Oct 10, 2015 9:56 pm

The change seems to have been made between the '79 and '80 model year boats, as TRW is a '79 with the bolt (also covered in goop), while ChrisB's boat is an '80, with wedges.
Tim Webb
1979 DS2 10099 The Red Witch
(I used to be Her "staff", in the way dogs have owners and cats have staff, but alas no longer ... <pout>)
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Re: Keel Inspection/Removal

Postby talbot » Sun Oct 11, 2015 1:17 am

I used to have a '79 with the new-style pivot, so I think the 79-80 year for the transition is correct. I suspect they changed because it avoids putting a big hole in the boat below waterline. The bolts that hold the retaining plates in are easier to seal than the gasket/washer around the old steel pivot. I've never heard of the nylon pivot failing, so I think it was probably a good change.
While we're on the subject, anyone got any advice on keeping the inside of the CB trunk in good shape? I got gel-coat blisters in there some years ago, and they were really difficult to repair because the damage was so inaccessible. Someone recently asked me how I would handle an invasive species inspection if I ever took the boat out of Oregon and tried to bring it back in. I was stumped. I suppose they could make me set up the mast, drag the boat off the trailer on the side of the highway, and careen it right there.
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Re: Keel Inspection/Removal

Postby Alan » Sun Oct 11, 2015 2:51 pm

I've been through two invasive species inspections with the Daysailer, one in Santa Clara County, California, and one on the California side of Lake Tahoe. None of the three total inspectors asked about the centerboard trunk. The biggest excitement was at Tahoe, where the inspector thought some little styrofoam crumbles in the bilge might be shells. He decided they weren't, and we went on our way.

I think if they did ask about it, I'd point out that the trunk doesn't retain water, and hope that was enough.
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Re: Keel Inspection/Removal

Postby IslandFarmer » Mon Jun 21, 2021 8:45 pm

FYI, there are more drawings and photos illustrating the chronology of DS II centerboard systems posted by Rod Johnson in 2005 on this thread.
Picture of DSII centerboard downhaul
viewtopic.php?f=2&t=4378&start=15

Keel Inspection/Removal
Post by Rakozy » Sat Oct 10, 2015 9:09 am
Rakozy wrote:In my boat, the keel [centerboard] pivots on a 4" round nylon core and held in place by two trapezoid shaped fiberglass blocks.. These blocks are held in place by the two stainless straps and bolted to the bottom of the hull. [...]
I hope this attached photo is useful to someone else in understanding your DS II.


SUNBIRD wrote:Re: Picture of DSII centerboard downhaul
Postby SUNBIRD » Mon Mar 24, 2014 7:31 pm
https://forum.daysailer.org/forum/download/file.php?id=243


Followup question.
Assuming the stainless plates holding my CB are held in place by screws as shown in Sunbird's photo (and that the threads are intact), do I need to do anything to the screws or holes when I put the CB back? (to ensure a good seal)
1983 DSII 12250
Stonington CT
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Re: Keel Inspection/Removal

Postby talbot » Wed Jun 23, 2021 1:14 pm

I would use a below-waterline, nonadhesive caulk. 3M 4200 probably.
Do NOT use 3M 5200, which will make it difficult to work on the CB in the future.
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Re: Keel Inspection/Removal

Postby IslandFarmer » Wed Jun 23, 2021 2:15 pm

Thank you very much, Talbot. I had a feeling I shouldn't just put them back with nothing!
1983 DSII 12250
Stonington CT
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Re: Keel Inspection/Removal

Postby GreenLake » Wed Jun 23, 2021 5:07 pm

On big boats, people prefer butyl tape when betting metal hardware. Easily removable and stays flexible.
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Re: Keel Inspection/Removal

Postby IslandFarmer » Thu Jun 24, 2021 10:34 am

Thanks GL. Interesting and I'm learning new vocabulary every day.

When my brother sent me this link,
https://www.westmarine.com/WestAdvisor/How-to-Select-Sealants-and-Caulk
I decided to do some research on my own . . .
For a current round-up, I prefer this website.
https://www.ridetheducksofseattle.com/best-marine-sealants/

After a lot of reading and some YouTube watching, I decided to go with Sikaflex 291, but it seems to be harder to find here in New England, so I'll be going with 3M 4200. : )
1983 DSII 12250
Stonington CT
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Re: Keel Inspection/Removal

Postby GreenLake » Thu Jun 24, 2021 3:47 pm

You basically have sealants and adhesives.

When you bed a bit of hardware on a fiberglass surface, if that hardware is held in place by strong bolts, you don't need an adhesive (it just makes taking things off harder).

What you want is something that can be compressed, but stays elastic (never hardens).

That's the combination of properties that you find in Butyl (commonly sold in tape form).

It's a different application from caulking or sealing an open gap, like around your bathtub. (And, incidentally, there's a reason people warn against silicone caulk on a boat: it gets into the fiberglass and makes it difficult if you ever need to paint it, even anti-fouling paint,if you keep your boat in the water).

4200 would be classified as an adhesive; even though it's not as bomb proof as 5200. 291 may be more simply a sealant, if I remember that correctly.
~ green ~ lake ~ ~
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Re: Keel Inspection/Removal

Postby IslandFarmer » Mon Jun 28, 2021 12:26 pm

Thanks for your thoughts GL.

In my research last week I turned up this 2012 post:
The Hull Truth - Boating and Fishing Forum > BOATING FORUMS > Boating How-To’s : The Kerno Memorial Forum > What sealant to use around screws?
https://www.thehulltruth.com/boating-how-s-kerno-memorial-forum/466901-what-sealant-use-around-screws.html

which referred to this excellent, illustrated step-by-step 2003 article about butyl tape by someone in the business, 'MaineSail' (a "Super Moderator") on SailNet:
Bedding Deck Hardware With Butyl Tape
https://www.sailnet.com/threads/bedding-deck-hardware-with-butyl-tape.63554/
in which he addresses when he does not use butyl tape:
Stuff under the water line, through-hulls near the water line, and anything that may be exposed to significant amounts of fuel, like the diesel deck fill, should also not be bedded using Butyl, since butyl dissolves in petroleum products.
[...]
While you probably could use butyl below the water line I don't, and use marine sealants instead such as Sikaflex 291 or a Polysulfide instead. 3M-101 is no longer marketed so you are left with Boat Life Life-Calk as the sole marine grade polysulfide. I never liked Life-Calk as much as 3M 101 but it's still better than "Satan's Glue", AKA 3M 5200.

#5 Tube Caulks - When you need to use a tube caulk for deck fittings choose one with LOW ADHESION. Polysulfides like Life-Calk are generally the lowest in adhesion but Sikaflex 291 @ 260 PSI and 295 UV @ 160 PSI are both less than 3M 4200 @ 300 PSI or 3M UV 4000 @ 300 PSI and a better choice IMHO. I generally prefer Sikaflex 295 UV for deck stuff and Sika 291 for below water, both 295 UV and 291 are polyurethanes with a 500% elongation rating.

It was this butyl tape article that led to my choice of Sikaflex 291, which I ended up ordering.
Sikaflex®-291 is a 1-component, marine grade polyurethane elastomeric adhesive and sealant. Used by many boat builders, its fast cure time makes it ideal for applications where speed is important.

https://usa.sika.com/en/industry/global-industry-content-pages-to-keep/commercial-vessels/elastic-sealing-bonding/watertight-sealingbonding/sikaflex-291.html

Having now removed the centerboard, whose setup is identical to Rakozy's 2015 photo, I found that the stainless plates were bedded with a white compound that is still soft and pretty sticky too. The bolts (not screws) appear not to have anything on them ... save perhaps a little of whatever was used to bed the plates. I hadn't actually thought of putting anything under the plates. . . . (Regarding exposure to fuel . . . although I don't have a motor on my boat, it is moored for 2–3 months in an area highly trafficked by motor boats.)

It was great having Rakozy's photo. Since the CB set up is functional, I decided to leave the centerboard resting on the inverted hull with the cable attached while I put 5–6 inches of antifouling paint in the CB trunk and the leading edge of the very top of the CB. Then replace the CB and paint the leading edge while vertical. Lastly paint the rest of the bottom, but that's another thread I'll read up on. . . .
1983 DSII 12250
Stonington CT
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Re: Keel Inspection/Removal

Postby GreenLake » Wed Jun 30, 2021 3:20 am

On thing we don't have on the DS is a bilge full of diesel fuel.

I like that guys thinking about low adhesion value. Your CB wedges are an interesting application, because they are below the water line, but unless you keep your boat moored/docked they are so only temporary. That might make all the difference.
~ green ~ lake ~ ~
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Re: Keel Inspection/Removal

Postby IslandFarmer » Wed Jun 30, 2021 8:13 am

Hi GL— Just to clarify. Posting here and there, I sometimes forget to include relevant information.
1. The CB wedges had minimal algal growth. They were loose in the space between the pivot and the plates. I'm planning to put them back just as I found them. (The centerboard worked fine last year, just didn't go up all the way by the end of the season because of algal growth and some barnacles on the sides.) I don't think the minimal algal growth on these wedges impacts CB operation.
2. My boat is moored in salt water for about 3 months — maybe a little less this year because I am repainting the bottom :) — so that is why I'm following MaineSail's advice to use Sikaflex 291 under the stainless plates.
Thanks for your replies. Great moral support in this endeavor with family pressuring me to just put the boat in the water ASAP!
1983 DSII 12250
Stonington CT
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