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I-28 Keel stub construction?

7K views 16 replies 6 participants last post by  downeast450 
#1 · (Edited)
I am wondering if the 1/2" steel plate I have inside the keel stub of my I-28 is standard construction. Please take a look at the photograph and share your thoughts.



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#2 ·
Keel Stub Compression Plate & hull id

I replaced the broken FLOORS in our i28. The bottom of our 1979 keel stub has an eighth inch thick resin coating so I was unaware of a steel plate but now suspect it is there. Now I can see why it was impossible to run a screw in to mount a bilge pump switch.

If the plate you see is in good shape, it goes a long way toward explaining why the keel stays attached so well...

You may have heard of the "Catalina Smile" which occurs when the piece of plywood they used as a crush plate - crushes ! The smile is seen along the front of the keel to hull joint. Literally, the front of the keel hangs down on the bolts as the plywood insert crushes.

Islander made a better boat.

Does anyone know if our sail number 2879 (from hull number) identify it as hull twenty eight of 1979?

Paul Comte
Milwaukee WI
SSYC
MASTracing.org
 
#3 ·
Paul,

If the "stuff" in my photo is a 1/2" steel plate that was attached to the bottom of the stub during layup of the hull with 5200 or a thickened epoxy mix and then glassed over, as would be necessary, before attaching the lead, it is one hell of a strong keel stub. I have been looking at keel stub construction in boats under 30' and have found nothing approaching this.

Do you have the "bead" of "sealant" running around the perimeter of the floor of your bilge? Mine was painted white and there were remnants of a layer of resin over the steel. The "sealant" looks like it was squeezed into the bilge around the stub's edge as things were tightened up.

Thanks,

Down
 
#4 ·
Down,
I believe that "sealant" is thickened resin which the builders probably mixed up and poured in the stub as a leveling agent / bedding compound. On top of that thickened resin, they "float" the plate which is cured into the hull. An extra step with better materials for a great boat...

If we cut the boat in half, top to bottom, I would expect to see the hull layup runs down the sides of the stub and are folded across its bottom. The plate provides an excellent loading point for the nuts of keel studs. Between the plate and the keel, the "bottom" of the stub distributes the loads to the hull.

If you get the opportunity to ride a few examples of i28, when driving hard to weather lift the cabin sole hatch, sit down and watch the stub work. An i28 I ride which has been raced summers for 25+ years, flexes to the degree it is easily noticeable to the eye. Another much less so and ours, since replacing the floors, very little. Not "rock solid" however as I think it needs to flex a bit to "save itself" from overloading the next link in the chain...
 
#5 ·
Down,
I believe that "sealant" is thickened resin which the builders probably mixed up and poured in the stub as a leveling agent / bedding compound. On top of that thickened resin, they "float" the plate which is cured into the hull. An extra step with better materials for a great boat...

If we cut the boat in half, top to bottom, I would expect to see the hull layup runs down the sides of the stub and are folded across its bottom. The plate provides an excellent loading point for the nuts of keel studs. Between the plate and the keel, the "bottom" of the stub distributes the loads to the hull.

If you get the opportunity to ride a few examples of i28, when driving hard to weather lift the cabin sole hatch, sit down and watch the stub work. An i28 I ride which has been raced summers for 25+ years, flexes to the degree it is easily noticeable to the eye. Another much less so and ours, since replacing the floors, very little. Not "rock solid" however as I think it needs to flex a bit to "save itself" from overloading the next link in the chain...
 
#6 · (Edited)
Paul,

I have finally come to the same conclusion. The keel stub on these boats was built very well. I have been corresponding with Bob Perry and he thinks so, too. I have not noticed the flex you describe under sail but will do as you suggest. I am finally relieved to understand that the keel stub and bolts are secure.

What was the source of the leak you discovered at the aft end of your keel/floors?

Thanks for sharing.

Down
 
#8 ·
Couldn’t find a photo of my bilge in the dry state. I do have the steel plate, and recall some sealant, but not as much as yours. I’ll look closer next week.

Interesting location for the knot meter; mine is under the starboard settee, where I believe many boats have a holding tank.
 
#9 ·
Charlie,

The knot meter has been relocated up on the hull and a little aft of this, the old, location. I am going to glass this hole in. There has been a dummy plug living in this hole since I got this boat. One less hole in the hull.

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#10 ·
I've got images of the before, during and after replacing the floors etc. Building a place to post, will advise when complete.

BTW, I had composed a couple of paragraphs on the rudder thread but lost them when this site didn't play nice...

I am also putting together some notes on plugging holes in the hull, will advise when posted. I'll try to get the rudder tube stuff in there too.

Also, the the very best things about i28 are Bob Perry design inspired. I understand he gave them the design and then they did the engineering. The few problems we face stem from construction and engineering which were the respobsibility of Islander yachts. The keel stub, floors, mast strut footing (on the plywood cabin sole) were all theirs (financial choices no doubt) and we are given opportunities to address these issues as required. An i28 could be made perfect but then we wouldn't have time to sail them. I prefer the manageable "working toward perfection" approach.

Thanks Bob Perry, I think of you each time I sail my most excellent boat.
Paul Comte
Milwaukee, WI
 
#13 ·
Hi, not a I-28 owner but this construction is first class.
The plate distributes the keel force more evenly and properly bedded would be a great improvment on the single heavy washers on my Westerly.
I have been thinking along these lines for a permenant cure to seepage into the bilges due to keel/hull flexing.
Can only link pairs of keel bolts at present due to bilg strengthening struts but it may be worth removing these as they require repair anyway.
I would be concerned about the amount of corrision visible on your keel bolts and nuts. It could be worse were it can,t be seen.
Regards
Brian
 
#14 ·
Down,

I’m glassing over and finishing all the fiberglass surfaces, I want to see the structure of the boat not cover it up. Inside the head I’ll finish the surfaces smooth and use a two-part paint system. In the other areas I’m not going to try to smooth things up much more than is shown in the pictures – will probably use a high build epoxy primer followed by a satin one-part top coat. The sole will be finished smooth and painted with a two-part paint system with some sort of non-skid.

The mast step was rebuilt using solid fiberglass for the section of sole and the floor beam below the compression post.

Mark
 

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#16 ·
Mark,

That is impressive work and a lot of it! I like the way it looks. I am going to do something about my ceilings because of other work I am doing but I had not considered glassing it all. Do you think you have added much weight? My 1977 hull has a vinyl ceiling with access zippers. A couple of the zippers are fused and the edges of the ceiling is coming loose in places because the staples holding it have rusted. I am considering teak or mahogany lath and trim.

Consider a Lavac head. I installed one and am very happy with it. it adds an emergency manual bilge pump, too. I will collect some pics of that install.

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