Need advice on keel fixture

[BaikalPeter]

Hey, everyone!
We are finished with our hull, with foil for the keel ready to accept the bulb.
There's no a question about how to fix the bulb, it is the upper end that arises questions...

How do I fix the keel in "down" position?
I attach pics of our keelbox deck aperture, note that I can only use bolts/screw on the cockpith floor level, not in the recessed area.
I will appreciate your suggestions or maybe ready solutions for the task.

DSC02551.JPG

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I would like to keep the floor as "flush" as possible and avoid any bulky installations...

[micah202]

.

...VERY nice work--almost looks like it's pulled from a mold!?

...with the foil-shaped trunk,,the keel blade will stay tightly in place unless -perfectly- lined-up with the trunk,,so there's little chance it'll slide when the boat's inverted!! ....

...but if you -want- to add a lock,,,how about a steel plate that's through-bolted on one side,which can swing across and slot into a bolt on the other side?

[ryderp]

I'm planning on using a swinging stainless steel plate to secure my keel down - I haven't gotten to it yet, but will some day. I'm thinking that it would be about 5" X 3/4" X 3/16". I'm thinking about using nylon washers to provide some resistance for the swinging motion, and that the strap wouldn't really be fastened on the other side.

I have had the boat over on its side a couple of times and the keel has stayed in place (huge spinnaker and lots of wind).

I second the comment on the beautiful work that you've done.

[Chad]

Assuming the rectangular recess will be for a plate on top of the keel? Then, I'd put 2 rabbeted rails on each side, so that a retaining plate could be slid under them and over the keel plate. Recessed fasteners, rounded edges, could be hardwood, glass, or machined G10, and hold it in place with a bungie...

[i550sailor@aol.com]

Great work, your boat looks beautiful. Here is a side view of an Ultimate 20 keel, it has an aluminum plate that bolts the keel down to the boat, it usually has (2) bolts screwed into the keel trunk. I am going to attach my keel like this, the crane works well also.

[micah202]

.

...VERY nice work--almost looks like it's pulled from a mold!?

...with the foil-shaped trunk,,the keel blade will stay tightly in place unless -perfectly- lined-up with the trunk,,so there's little chance it'll slide when the boat's inverted!! ....

...but if you -want- to add a lock,,,how about a steel plate that's through-bolted on one side,which can swing across and slot into a bolt on the other side?

...in addition to what I'm saying above,,,I really suggest a more -open- box design as I've mentioned before,,,I have a mold for the trunk,,,happy to share at a nominal cost....this design adds much convenience in raising/lowering the keel compared to a tighter foil-shaped trunk,,and adds a lot of safety in the event of a 'grounding'

...............the white blocks visible,,bolt onto top of keel,,slide into slot and lock the keel in place.,..the bolts holding blocks to the keel can sheer if run aground,,while the keel's top-plate keeps the keel from disappearing in such a mishap

.......pour-in-place foam ,visible at front of keel,was poured into 3 plastic bags ,,nicely filling the trunk so water doesn't bubble around.

[noemar]

micah,
I would be interested in acquiring information on your trunk mold.
Noemar

[micah202]

micah,
I would be interested in acquiring information on your trunk mold.
Noemar

...first off,,,I don't want to be competing with 'justwanna',,,I'd be happy to provide a sample trunk to him if he wants to replicate,,,,,
,,,,,,,,,but otherwise,,,I'd say that it'd be ~$250 plus shipping to mold a trunk,and custom shape the 2 hard plastic blocks to fit your blade thickness.

[jray]

Looks like a great setup! I knew you were doing some mods to the Offset. How far forward did you move the cockpit? It will be interesting if it helps upwind. Do you have any pictures?

[micah202]

Looks like a great setup! I knew you were doing some mods to the Offset. How far forward did you move the cockpit? It will be interesting if it helps upwind. Do you have any pictures?

...I posted these before,,but here yer go again...
...the bottom pictures show the difference in profile the most,,,be sure to 'click' on pics to get descriptions....
http://www.flickr.com/photos/59103003@N ... 076955693/

....in the 2nd pic,,the blackline(moving to red pen-line to accommodate the jib track) on sidedeck,,and tape line on the cabin show the cuts---quite a difference
.......you can see the keeltrunk sitting on it's own on the sterndeck.

..the 1st pic shows the trunk in place,,I put the port side-deck back in place to show the huge difference in designs.

.......my resulting side decks are a fair bit narrower than anything else I've seen,,,,,,helps encourage crew-weight outwards,,,not a bad thing! ......and there seems to be no detriment in waterflow,etc for having such narrow deck,tapering to ~7-8'''' width at the stern....
........I can't for the life of me find a reason to justify sleeping space for the 3rd and 4th person belowdecks(!!!) over the sailing qualities of the boat--i.m.o,,you'd have to be planning a LOT more family cruising than racing to warrant the wide side-decks as in the plan choices..........but of course that's the beauty of 550's --you build to your choice!

[jray]

Thanks for the picts. I'm happy that it's not in my garage. Lots of work ahead. I just have to ask is that a live well for bait forward of the strut? Going fishing between races?

If you've posted these up before I must have missed them. Since my build is done I don't look at blogs often. Looks like your going to frame 89 with the cockpit.

[micah202]

Thanks for the picts. I'm happy that it's not in my garage. Lots of work ahead. I just have to ask is that a live well for bait forward of the strut? Going fishing between races?

If you've posted these up before I must have missed them. Since my build is done I don't look at blogs often. Looks like your going to frame 89 with the cockpit.

...don't worry those pic's are -old-!!..completed ~july '12........hmmm,Jray it seems you haven't been using your resperatereraterator!....your comments are all over that thread!

..the whole story's at 'carbon offset's reno' thread ........ http://i550class.org/forums/viewtopic.php?f=3&t=177

and 'continuing adventures of carbon'........... http://i550class.org/forums/viewtopic.p ... 3392#p3392


.......it's probably best to let -this- thread get back to topic,,,go have a visit--there's a lot of lessons learn't and shared there,,might save a few some time if yer willing t'learn from my mistakes!

[Tim Ford]

SO, instead of drilling vertical, threaded rods into the keel foil to attach a plate or "cap" to keep it from falling out of the boat, I thought I'd go with a cap on the top of the keel with rods or pins inserted
horizontally, such as in the drawing. Question is: what sort of plastic do you think would work well with this and where can one get it?

It can be pretty wide, I have some latitude at the top of the keel b/c as it is, I'll draw ~ 3 inches more than the class maximum.

I think Chad used this kind of arrangement, too. (Can't find the thread or photo)

whatta ya think?

SomeKind of Plastic.jpg

[ryderp]

I would use Garolite G10 for that design. You can buy it pretty thick.

Phil

[Tim Ford]

Problem is with G-10 is I can only find thickness to 1"
If I use 3/8 inch pins, then that only leaves 5/16ths of thickness above and below the pin, or with 1/4 inch pins, then 3/8ths thickness above and below. Is that enough? I was thinking more like at least 1.5" thickness to get 5/8ths thickness over a 3/8inch pin hole.

OK, I guess I'm only supporting 170 pounds, but that doesn't include the dynamic load when the boat slams in a seaway....

[ryderp]

McMaster Carr has G-10 up to 2" thick, but it isn't cheap. Here is a picture of my keel cap. I made it with a sheet of 316 Stainless inside of a bunch of layers of carbon fiber. I used 1/2" stainless bolts, washers, and nuts. I like the "ikea" method because it's easy to take the cap off if I ever need to remove the keel (which unfortunately I did have to do).

KeelCap.jpg

Phil

[Chad]

Ugh, Tim- I don't like that!
(I did a plate on top with a big ol' honking threaded rod epoxied vertically into the foil. I also added some cross-bolted delrin shims to take up the slop at the bottom of my rectangular keel box- maybe you're thinking of that.)

Problems with this cross-bolted plate design are as you describe- not enough meet for the plate or keel end to develop enough sheer strength. I suppose the plate might be alright if the pins are big enough, since the plate is just acting as a spacer to keep the pins from resting right on the deck. But unless you've got some meat above the pins on the keel end (end distance of 7 fastener diameters is a general engineering minimum), the keel will be swimming with the fishes all too soon.

It's useful to minimize the profile of the keel top, and soften and round all the edges, and even pad the whole package a little. I speak as one who has crewed on my own boat, and crossed over the keel and under the boom a few times. My knees left a bloody path from side to side...

If you want a cross bolt solution, maybe two pads of delrin, maybe 3/4" thick x 6" long x 2" high, with at least 3) 1/4" machine bolts all the way through, and leave at least an inch of keel above the delrin. The 3/4" delrin will bend to the relatively flat middle part of your keel. Tell your crew the protruding keel is a foot chock, and give them a sharpie to sign their name next to the blood drops...

Or just get a plate of 1/2" G10 and drill and epoxy from the top. If you don't trust the glue by now, you've chosen the wrong boat (I tell my crew that occasionally too).

Edit- I see Phil's pic. That works too. Mine is similar, but I just bonded a piece of all thread into the keel, and I use a nut to secure the plate.

[Mist]

When purchasing G-10 from McMaster-Carr be careful to get the right stuff. I purchased tubing once, mistakingly I ordered G-10/FR4. The FR4 specifies flame resistant and the product description mentions 'brown'. You don't want this FR4 stuff. It is fiberglass reinforce with a varnish substance not epoxy, which is much stronger. Just make certain you order the yellow-green stuff and you'll be ok.

[Tim Ford]

Thanks for the replies everyone. Here is a better drawing, does this seem more sound? I think the first drawing was poorly done and poor in concept. How does this stack up?

Someone on another super-secret forum (bunch of cruisers) said they DID like the pins in sheer more than bolts in suspension....this sorta employs both, from a belt and suspenders perspective.

keel stop.jpg

[Chad]

Is there any radius around the opening at the top of your keel box? -if so, make sure the HDPE reaches beyond that/is thicker than the radius so it does wedge in there.

Bolts and pins in shear are great, but the end of a wood board (keel foil) isn't. A wide band with several small fasteners will work, as you show, since it ensures a bunch of end distance. But the whole thing sticks way up outta the cockpit sole this way. Bloody knees.

Instead, it takes no additional effort to just upsize the plate rods until you're not worried about it, and then the plate can sit nice and flat on your sole. I used a single 5/8"ø piece of all thread, and it is crazy stout, by a factor of about 30.

[i550sailor@aol.com]

Thanks for the replies everyone. Here is a better drawing, does this seem more sound? I think the first drawing was poorly done and poor in concept. How does this stack up?

Someone on another super-secret forum (bunch of cruisers) said they DID like the pins in sheer more than bolts in suspension....this sorta employs both, from a belt and suspenders perspective.

keel stop.jpg

Tim,,, I am not too sure if your plan will work, the drawing is not to scale,,,,, jut kidding,,, I think all this sanding and dust are getting to me. I am going to do my top plate in aluminum, topped with a piece of EVA foam to keep the crew from getting bruised.

[Tim Ford]

Chad, I forgot to tell you. My keel box is recessed by more than a few inches, and has a cover plate that fits flush with the cockpit sole. (see foto)

i550oct11aa.jpg

CompressPost.jpg

No cuts and bruises there. It's recessed b/c the first thing I ever did is build my keel. I built the keel to fit in a keelbox spec'ed for the Long Cabin variation of the original boats. They used a 9 inch high keel box that sat down inside the cabin. Then, months later, I received the kit from Watershed and it was a short cabin kit! So I built the boat as it came and figured, if a 9 inch tall keelbox was sufficient for the short cockpit version, why wouldn't it be sufficient for the long cockpit version? The added bonus is it sits out of the way.

and hardly any radius at all, it's pretty much a 90 degree angle. I ran material out to the sleeve and cut it off square with a dremel tool. If there's any radius, it's less than 3/32nds.

HAH! you and me both, i550sailor. I was sanding my bulb this past weekend (the nasty 2-part epoxy paint) and realized after about 2 minutes that I didn't have a dust mask on. Another 50,000 brain cells bite the dust....

[Chad]

Sheesh- yeah, just bolt a couple cheeks of delrin, HPPE, or even kitchen cutting board- to each side. Forget a cap plate. The plastic needn't be the full foil length, 6 or so inches on each side is plenty. Easy!