Can my Keel be too stiff / ridged ???

[VKRUE]

I'm back to work on my 17 footer again...... I'm re-constructing the entire floor. This boat has been worked on in the past by who knows who, so I'm not sure what was original and what is not with regard to the few different pieces involved in the structure of the floor.
My question is this, can the keel become too ridged or stiff? I'm wanting to use blocks of wood to support the center of each cross brace between the brace and keel. I'm sure of one brace and block being an "original design" part but, the others have been replaced at some point in this boats past and did not have any blocking under the brace like the first one.
The pictures show the blocks and braces (sorry, I'm not that savvy regarding proper names of things in the boat world) that I've made so far. I have two more braces to install yet but, I've started to wonder wether or not the keel is supposed to be able to flex.

Any comments will be greatly appreciated.

vkrue

[VKRUE]

Well, maybe my question is too dificult for the folks here...
I'm not a designer or builder and have no experience in this area so, I thought it a simple thing to ask, and... better safe than sorry in my opinion. 42 people have looked at my thread over the past several days and not a single opinion
My boat is not as big and glorious as most around here and I'm not sailing in open waters of the coast of Thialand or Australia but, we all have one thing in common................................. we love to be out on the water !

Thanks anyway (for nothing), work will proceed as intended and with the grace of God, everything will work out just fine.

[Pete Dennison]

Having no "trained" or "certified" knowledge of an answer to your question, I'll try to give my opinion for what it is worth! I've owned 10 or so boats of various sizes over the years and currently I'm converting a 50" ex-fishing trawler for pleasure use. I've also owned (and worked on!) a few yachts and one thing is common to all these craft and that is the keels were STIFF! And I mean the stiffist, most solid aspect of each boat! My last yacht (a 38' sloop) had a 2 metre deep solid piece of cast iron and lead - now that's stiff! The mast step from the deck to the keelson had enormous downwards pressue so the keel HAD to be stiff! My current boat, the trawler, has a solid slipper of 10mm steel in a "C" section down it's entire 45' to make it stiff. I believe the keel is the base that the rest of the boat is supported on so it needs to be solid or stiff. If it flexes then the ribs and planks would work free and fall off! So brace away Vic! I reckon you're doing the right thing! If I'm wrong it might at least encourage a few more replies to your question!! Cheers! Pete.

[VKRUE]

Many thank u's Pete...

I had suspected it to be much as you said... STIFF - with a capitol STIFFFF. Like I mentioned, during one of the previous restoration / "Fresh Paint" jobs that this boat has had in the past, the blocking must have been removed or they neglected to replace them.
I've got this thing completely gutted and stripped so I want to do evertything to the best of my ability, therefore the only limits being my skills.

Again, thanks you for your reply.

[Pete Dennison]

No worries mate! At least there are two people in this world that agree on something! The only other thing you might want to consider if you are installing a bilge pump is the movement of water along the bilge to a central collection point. Couple of 1" holes drilled through your braces should do the trick there! Good luck with the project! Pete. (At least the thread's got 4 replies now!!! Hehehe.

[DanishBagger]

I would think (yes, I am no engineer nor naval architect), that stiff is good.

Unless, of course, that the stiffness is concentrated and not transfered over a wide area.

If not, it would strain /(stress?) the area where the part that is stiff is attached.

Did that make sense?

[VKRUE]

D. Bagger:
Yes indeed, it makes good sense. Thank you for your input.

Mr. Pete:
Yes, I do intend to incorporate a bilge pump... actually two !
The keel itself separates the bilge into two halves... Port & Starbard.
If the water gets higher than the keel (which is 1 7/8" thick as well as wide )then the two sides become one, more or less. So, I thought, rather than drill out the keel (lessoning it's structural integrity) to allow water to flow between the two sides, I would just use a separate bilge pump in each side.

Thanks again guys.

[emrenergiz]

i am a student in naval architecture, agreed with the opinions above, keel must be stiff and this part must be done carefully; the forces on the keel must be distributed to the hull so that there wont be any discontiniuties that thakes more pressure than other sections of the keel. keel keelson and stations and also the shell are supported by the keel. stiff is good. Sorry for my english and lack of vocabulary.
best wishes.

[VKRUE]

Thanks Emren...

She's not a big boat nor is she of special breeding but I hope to do her right just the same... I've got more time and money into her than she will ever be worth (being plywood and only 17' long and all...) but, I like to think of her as MINE .

Thanks again.................