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View Full Version : A Split Keel, and a Perfect Transom. Ingenuity and lack of experience!!!!!



SeaDreamz
09-02-2014, 09:56 PM
So in attempting to bend my keel, I've managed to split it. It seemed to have no problems during the bending, but as it was cooling it cracked and split in a VERY loud fashion. In research on these forums, I've found I made a few mistakes. No backing blocks on the 'tight' portions of the bends. I also didn't fair the floor frames to match the bend prior to trying to make it.... Anyhow, here is what the keel looks like now:

http://i.imgur.com/yoWRILU.jpg

It does not appear that the split has gone deep enough that it cannot be fared out. However, I would rather not worry about any sort of weakness at the bow of my boat. That said, as I see it I have the following options:

#1 Fair it in as it lays, and forever have concerns about the strength of the bow of my boat

#2 Remove ALL of the split wood and add another scarf joint just behind frame #4 And re-bend the keel properly, without splitting it (hopefully)

#3 Remove everything to aft of the original scarf joint and start over (majority of the keel).

What do you all think?


I also cut my transom this holiday weekend. I was not about to risk screwing up plywood that cost me $170/sheet and a 6hr round trip to New Orleans. I made every cut 1/4"-1/2" wide, marked the angle with an adjustable square. Then brought it closer with the jigsaw and closer still with a belt sander. Once I was no longer comfortable with the belt-sander, I made some interesting tools to get it 100% perfect.

What I did was measure the 3 angles out perfectly on a table saw with a compass style angle finder. I cut some small blocks of hardwood to the perfect angle, and used them as "backers" on a 'long-block' for sanding. Here is a pic of the blocks and their backers I used to set the angles:

http://i.imgur.com/C2yCxTD.jpg

Getting the initial angle was tough, but using this adjustable square was a GOD-SEND!!!! Also, I initially tried to set the Arc for the top of the motor outlet using the "nail and string" method I used during my House Framing days.... Not nearly accurate enough, the 'large circle compass' in the pic with my adjustable angle finding square made it happen!

http://i.imgur.com/TbLxxwT.jpg

Here is what we ended up with. I may have split my keel.... But I do believe I got this part right!

http://i.imgur.com/2PZhbO0.jpg

Skiff Man
09-02-2014, 10:53 PM
Runout! Why not laminate the stem out out of 1/4" slivers of Southern Pine? Extremely strong, durable and gluable if heartwood.

TerryLL
09-02-2014, 11:05 PM
Does the SSS20 really have that much bend to the froward keel? The plans for this boat show a very gradual bend to the forward keel with evenly spaced floors. Those two forward floors look way too close together. Might be time to recheck the floor layout.


http://www.timelessboatworks.com/sites/default/files/images/SimmonsSeaSkiff/lines.jpg

SeaDreamz
09-02-2014, 11:21 PM
Does the SSS20 really have that much bend to the froward keel? The plans for this boat show a very gradual bend to the forward keel with evenly spaced floors. Those two forward floors look way too close together. Might be time to recheck the floor layout.


http://www.timelessboatworks.com/sites/default/files/images/SimmonsSeaSkiff/lines.jpg

Double and Triple checked before I cut the slots. From the build guide provided;
"Aft Edge From End of Jig"
Stem Heel: 168 1/2"
Frame #1: 164 1/2" (6" difference)
Frame #2: 159 13/16" (less than 5")
Frame #3: 142 15/16" (~17" the largest gap)

SeaDreamz
09-02-2014, 11:24 PM
Runout! Why not laminate the stem out out of 1/4" slivers of Southern Pine? Extremely strong, durable and gluable if heartwood.


The "Stem" is already built from laminated Red Grandice... It's the keel that split. Really don't want a laminated keel, or chines.

TerryLL
09-02-2014, 11:33 PM
Double and Triple checked before I cut the slots. From the build guide provided;
"Aft Edge From End of Jig"
Stem Heel: 168 1/2"
Frame #1: 164 1/2" (6" difference)
Frame #2: 159 13/16" (less than 5")
Frame #3: 142 15/16" (~17" the largest gap)

Can you post a pic of the floors in profile and plan view from the plans?

Skiff Man
09-02-2014, 11:35 PM
If it broke then you needed to laminate it. There is no shame in it.

Peerie Maa
09-03-2014, 06:13 AM
I would cut away the run out wood and laminate in a replacement layer. It will need to be about three feet long or more to ensure that the ends stick down. With the new layer glued in and solid, refair to the specified thickness.

wizbang 13
09-03-2014, 06:40 AM
The "Stem" is already built from laminated Red Grandice... It's the keel that split. Really don't want a laminated keel, or chines.
The whole boat is laminated, it is plywood.
Steaming could be your mistake.
The split is long , stick some epoxy in there are clamp it up .
and for gawdsake build a proper strong back.
When ply comes together, at stems and chines, is where it is STRONGEST! . The wood that makes up a stem or a chine log gives no strength, it is only there to hold the fastenings. A chine log is not a stringer.
bruce

wizbang 13
09-03-2014, 07:03 AM
http://i.imgur.com/J7xaDsC.jpg

wizbang 13
09-03-2014, 07:05 AM
WTH is up with the fwd floors so close together? It broke right ON the second one in .
Chine logs are not stringers .
S n G boats have no chines , and they do not need stems.
Just extra wood in an old fashion boat construction.

TerryLL
09-03-2014, 07:07 AM
Double and Triple checked before I cut the slots. From the build guide provided;
"Aft Edge From End of Jig"
Stem Heel: 168 1/2"
Frame #1: 164 1/2" (6" difference)
Frame #2: 159 13/16" (less than 5")
Frame #3: 142 15/16" (~17" the largest gap)

There is a problem with the position of the forward floors. Here is what they should look like:

http://photoutback.com/wp-content/gallery/the-boat/pict0017.jpg

wizbang 13
09-03-2014, 07:42 AM
...But filets have ho fore n aft strength, that comes from the ply making an angle. A wood chine log could be built of many one foot long pieces, other than not running fair,no problem.
All it does is hold the fasteners, like I said.

Peerie Maa
09-03-2014, 07:53 AM
...But filets have ho fore n aft strength, that comes from the ply making an angle. A wood chine log could be built of many one foot long pieces, other than not running fair,no problem. All it does is hold the fasteners, like I said.That is true if the ply is thick enough to do all the work of the web or flanges of the hull girder. If it is marginal keel, chines, and gunwales also add longitudial strength, like the bilge stringer of a round bottomed hull.

SeaDreamz
09-03-2014, 08:00 AM
It's apparent that there is something off with both the spacing and depth of the first two frames in the strongback. Which is fantastic, as I followed the build guide table EXACTLY. I have no idea what "right" is or looks like. Hopefully the transom dimensions were correct. I laid out the motor well last night, but I didn't cut it because there is NO WAY the dimensions of the sides were going to line up with the forward part of the well.... An accurate set of plans & build guide would make this a lot easier. Guessing is not in my nature.

TerryLL
09-03-2014, 08:03 AM
It's apparent that there is something off with both the spacing and depth of the first two frames in the strongback. Which is fantastic, as I followed the build guide table EXACTLY. I have no idea what "right" is or looks like.

Again, can you post some information from the plans? A profile view of the forward floors would help a lot.

SeaDreamz
09-03-2014, 08:12 AM
I won't be able to post photos from the plans until I get home this evening. This "Job" thing really gets in the way of my boat building!

wizbang 13
09-03-2014, 08:16 AM
No erster , I am not going to forgo filets in my plywood boats.
But I am not going to use wood chine logs or wood stems in them either.
This is a 50 year old design here ,no?

SeaDreamz
09-03-2014, 08:19 AM
A lot of the wood along each side in the forward area is removed . This also will remove a lot of the stress in the grain. Try shaping before you do anything. And don't use SYP.


Erster, what is "SYP"? Also, being that you've built a few of these does there look to be something off about the spacing and depth of the forward frames? After looking at TerryLL's photo closer, I wonder if he and I are even using the same plans. His floors seem to be MUCH deeper than mine.

Ryan

TerryLL
09-03-2014, 08:33 AM
After looking at TerryLL's photo closer, I wonder if he and I are even using the same plans. His floors seem to be MUCH deeper than mine.

Ryan

It's a photo of typical SSS bottom framing. All the examples of SSS bottom framing I've seen show evenly spaced floors.

SeaDreamz
09-03-2014, 09:23 AM
So, I'm doing all this from my phone so we will see how it works. Below is the table from the build guide, along with a table I built to verify the spacing. So, according to this and if my math is correct, either the build guide is wrong (definite possibility) or the floor spacing is anything BUT even

http://i.imgur.com/qutrkCe.png

http://i.imgur.com/KJIFDC6.png

TerryLL
09-03-2014, 09:36 AM
So here's another pic I came across of the SSS-20 building jig. I does appear that the forward floors are closely spaced on the 20. I still would like to see a forward profile view from the plans.

http://www.timelessboatworks.com/sites/default/files/images/SimmonsSeaSkiff/Floors/floors16.JPG

pvg
09-03-2014, 10:05 AM
I won't be able to post photos from the plans until I get home this evening. This "Job" thing really gets in the way of my boat building!
In the angling community, we used to say, "Work is the curse of the fishing class..."
pvg

Gib Etheridge
09-03-2014, 10:15 AM
That's not enough runout to have caused that splitting in a well steamed piece of green lumber of a species that lends itself well to bending. I don't recognize the species, and my first thought was "Kiln dried".

Like Erster said, if you remove most of what you'll need to remove to shape the bevel before bending that will relieve some of the stress.

Also, as Terry pointed out, the bend looks more severe than the bend in the plans. Perhaps your heights are exaggerated? Maybe it's just camera angle.

And I agree, those 2 floors seem unnecessarily close together, but that didn't cause the fracture.

I would start over with green lumber, no big deal, and don't be discouraged, just go at it slowly and carefully,

It would be a really easy one to laminate.

Skiff Man
09-04-2014, 10:24 AM
Go with option #1 above. The compression face of the keel has made the bend without visible damage. The bottom ply and outer keel will splice over the tension face of the keel with the runout failure. There isn't that much stress in the center of the keel assembly in any case.

On a side note...If you prebevel the keel you would increase the stress on the tension face during the bend. Centroidal axis would move away from the narrowed tension face, yet structural depth and bending curvature would stay the same. So strains and stress would go up on the narrow face, and down on the wide face.

Phil Y
09-04-2014, 04:17 PM
I don't know how you guys cope with imperial measurements. That table does my head in just looking at it.

Gib Etheridge
09-04-2014, 06:18 PM
Use it or lose it!:) (javascript:void(0))