Oil Canning?

Hank · Post by **Hank** » Tue Jan 30, 2007 1:08 pm

Hi -

Just found this place via wikihow.com (they have a how to build a canoe in a weekend entry that links out to here). I'm currently at step 0 (or maybe -1) of building myself a boat; I need to clean out the garage to make room for such a project. The cleaning out part will please my wife. The filling it back up again with boat parts will probably take a bit of explaining...

But back to the topic. I've read a large fraction of the posts here and have compiled a few questions. The first involves the dreaded 'oil canning'. People refer to it and grave noises are made and there might even be scratching of chins. But I'm still trying to figure out what it is. So, if I may be so bold, what is oil canning?

Thanks,
- Hank

Post by **jem** » Tue Jan 30, 2007 1:14 pm

It's when the bottom of boat flexes inward toward the paddler. I suppose this could happen on the sides of a boat too.

It can be unnverving to see but can also lead to hairline cracks in plywood not covered in fiberglass after a while.

Kayak Jack · Post by **Kayak Jack** » Tue Jan 30, 2007 2:43 pm

Hank,

If you haven't cleaned out the garage yet, you are at step -2. Next comes -1 and finally zero. Cleaning out the garage will generate at least two more projects that are currently laying in the weeds.

Are you planning to build a flat bottomed boat or a semi-rounded hull? If you plan a semi-rounded hull, forget the problem. They form a shallow arch and are self-bracing. Extreme force concentrated in one spot (like, when you run a fully loaded boat up onto a sharp rock) can overcome an arch momentarily. But, most times, a semi-rounded hull will simply slide off rocks and shrug them aside.

Flat bottomed boats are more likely to oilcan, and much more likely to get stuck on a rock. Simple slats on the inside or outside of the bottom can limit the oil canning. Polarized glasses and learning to read the water will limit, somewhat, running onto rocks etc.

Oldsparkey · Post by **Oldsparkey** » Tue Jan 30, 2007 2:46 pm

Hank

Matt explained what it is in reference to boats.

Now, you need to be ancient like me to know where the term originated.

It is from the old fashion oil cans that were permed shaped with a long spout on them ( I still have one) . A person would unscrew the spout from the can and fill it with oil , then screw the spout back on the can.

When using the can the person would invert it , put the spout where they wanted the oil to go and push in on the wide bottom of the can with there thumb to force the oil out of the spout.
This action would make the can have a thunking sound as the bottom was pushed in and then as the pressure on the operators thumb would relax the bottom would pop back to the original position so it could be pushed in again to release some more oil from the spout. The bottom of the can would flex ( with some thumb pressure) in and out.

OK.. Class is over now get back to work on your boat.

Chuck.

Hank · Post by **Hank** » Tue Jan 30, 2007 4:02 pm

Thanks for the responses. It makes sense now.

As to which boat, I am at the moment leaning toward a Merrimac (which isn't flat bottomed, so I won't need to worry about oil canning). I've got two young-ish boys so getting the whole family into one boat until the boys are big enough to paddle around on their own seems like the way to go. The Merrimac looks like it's big enough to fit the bill, not too hard to make as a first time effort, and small enough to fit in the garage during assembly (after the cleaning out and the other mystery tasks get taken care of).

- Hank

Post by **jem** » Tue Jan 30, 2007 4:26 pm

Merrimac is a nice choice.

You can get oil-canning any time you have a flat panel that is about 9" or wider. Many factors also go into that.

Merrimac has 2 wider panels on the bottom. You might see a little flexing inward, but the plans show you how to address it. You can add extra fiberglass or some flat bars ribs to the bottom.

It is not a hard problem to solve. I have a bunch of pictures of the merrimac I need to get posted.

Oldsparkey · Post by **Oldsparkey** » Tue Jan 30, 2007 5:11 pm

Most boats will have some degree of a minor flex to them because they are made from wood and not steel or iron. A fiberglass encapsulation of the boat takes care of that problem.

Remember the boat was made from something that was living and a part of Nature , Nature flexes , man made items usually don't , this is why I like to think of my boats as being alive and a part of me ... unlike asphalt , cement , plastic , steel or iron.

A wood boat takes on the qualities and character of the maker who eventually becomes the paddler when it is done , You are not paddling just a boat you are paddling yourself and for that reason they do have there own personalities , quirks and faults just like us.

On the other hand they bring beauty , comfort , relaxation and pride to the builder since each boat made from wood is totally different from any other ones. You will never find two made from the same plans exactly alike , this is the beauty of them , they have personality.

There is something intoxicating for the body and spirit to be in a wood boat you have made and are paddling , there is no other feeling like it in this world. You are one with the boat , not two separate alien items.

It is hard to put into words the only way to understand this is to build one and then see what I am saying.

Now if you build one then one of two things will happen .... You will say one is plenty or you will want to build a lot more. There is no middle ground when building wood boats unless you are a really rare type of person that only wants one boat.

99% of the time it is .. I want to build more boats, the simple fact is that you have a boat , custom made by you and it is one of a kind for a lot less then someone who went out and got one off the shelf made by a machine and is a clone of everyone else made. Plus the cost (besides your labor ) will be a lot less. I can build a canoe for $300.00 to $350.00 that you would purchase from a store for $1,200.00 to $2,500.00 , same type but not the same boat. Mine is custom made for me by me the way I want it.

Chuck.

Oldsparkey · Post by **Oldsparkey** » Tue Jan 30, 2007 5:59 pm

I sure hope Matt does not mind me posting this but it is a good item to show how the canoe looks and handles. With some of the BS we throw around on southernpaddler.

Here are the construction reports by the builder.

viewtopic.php?t=913

When it was done
http://www.neilbank.com/phpBB2/viewtopi ... 6a5167679a

1st trip.
http://www.neilbank.com/phpBB2/viewtopic.php?t=2781

Another outing.
http://www.neilbank.com/phpBB2/viewtopic.php?t=2891

Chuck.

Kayak Jack · Post by **Kayak Jack** » Tue Jan 30, 2007 6:15 pm

Hankus Paddleicus,

First of all, my sincere congratulations on undertaking a project with you kids. One of my tenets sez, "You won't be building a boat with boys - you will be building boys with a boat."

Chuck mentioned a concept - encapsulation. What that means in practical terms is, if you put epoxy and glass all over the boat - inside and out, it will become really quite strong. Glass inside is important; it completes the other half of the glass sandwich. Plywood is the peanut butter part. Also, inside glass will prevent cracking if you are somehow successful in impinging upon a rock.

hairymick · Post by **hairymick** » Tue Jan 30, 2007 8:36 pm

Yep Hank what Jack said, when translated into aussie speak is "good on ya Maaaaaate

"

Building boats with your kids is one of the most rewarding things a bloke can do. The merimac is a fine looking canoe and should suit your needs very well. Good luck mate.