Where Should You Place The Oar Sockets?

Sorry i know this is an over aksed question but I cannot find the answer i'm looking for. I have a few questions. What is the aft? and Where should the oar sockets be installed? how far from the seat? inside the boat or outside the boat? where should the seat be? I'm building a 6.5' flat bottom Jon boat, and i have everything done but the seats and sockets.

Thanks,
skid

 

The average height is about 8" above the thwarts. The fore and aft depends a lot on the kind of seat or thwart you have. If they are sliding seats, about 10" aft of the middle of the travel. If they are fixed about 10" aft of them. However, depending on the freeboard and your preferences that changes quite a lot. For example whether you use thole pins, a thole pin and strop, oar locks, etc. will affect location.

 

Forgive me if you already know this, but it appears you are asking something very basic.

The "aft" is a direction, it means towards the rear of the boat. It is not a part of the boat, but the term sometimes get used that way. You can "move aft" or you can "store your tool box aft".

towards the front is the more obvious "forward".

Bow is the front, sometimes they call the front the "stem", this is a term referring to specific part of the bow (hence the term "stem to stern", ie. front to back). the stern is the rear of course. the Stern is always "aft" and bow is always "forward".

"Starboard" is the right side as you face forward (it is an ancient term for the side of the boat where the "steering board" or rudder was mounted). On larger boats it is not useful to refer to the right side as the right side because you could be below decks and facing any direction in a large boat without reference to the "bow" or front, so the actual left and right side of the boat is named. the "port" side is the left side when facing forward, and it was the traditional (and often still used) side that you bring the boat to port (because the "starboard" was in the way on the other side). Interesting btw, that all commercial aircraft load passengers to this day from the "port" side, even though they never really had a "steering board". the other side on an aircraft is still called "starboard" as well.

It is important to know these terms even if you do not do much boating. If there is an emergency and others or the Coast Guard comes to rescue you, you may be given instructions using these terms.

Welcome to the forum BTW.

 

In a boat as small as 6.5' the single most important location would be the longitudinal or fore-and-aft position of the seat, which in turn depends on the shape of the boat.

The height of the seat could depend on comfort and rowing efficiency in a boat with adequate stability, but preventing the boat from flipping over might be more important. Depends on the shape of the boat, especially the width or beam.

The values for distance from seat to the oar sockets (are you using oarlocks?) that Gonzo provides are reasonable for most boats and people but again, in such a small boat compromises are often needed.

As a simple example of the compromises that may be needed, if the boat is narrow short oars are needed (Google "oar length") but short oars are inefficient; there is the option of rowing with hands overlapping allowing longer oars to be used, but if the seat position is low the knees may interfere with the rowing action.

These matters are normally figured out by the designer and provided on the plans, if you have them. If you don't, I suggest you show us a picture or drawing of the boat and also provide your own size so we can form some opinions. Once the seat is in place eveything else can be determined.

 

I never get it right the first time. The location is dependent on the boats shape at your geometry and rowing style. An inch or two this way or that way makes a big difference.

Since I know that the location is critical I prefer to use this style oar lock because its simple to move.

A thwart that allows fore and aft movement, to fine tune the rowing geometry, is also a nice detail

http://

 

First if this is a single hull rowing boat the oars should be about twice the length of the boats width. My twelve foot rowboat which is exactly 4 feet wide, has 7' 6" oars. (I couldn't find 8 foot and I didn't want to make them myself) To determine position of the oar locks, sit in the rowing position facing aft (the back of the boat). With the oars straight across the boat (not angled aft or forward) they should be just slightly aft of where your hands are when your upper arm and forearm make a right angle. Or with arms full extended, the oars should be angled at about 45 degs to the side of the boat. Find a comfortable position. Mark it on the gunwale of the boat.

Whether the oar lock sockets (tholes) are on the inside or outside depends on the balance of the oars when your are holding them in the sitting position. They should have about 2/3 of the length outside the boat, but you don't want the grips to hit each other. You want enough weight in the blade end of the oar so it just normally falls into the water, but no so much that it is hard to elevate the blade. I just experimented with inside and outside and ended up mounting them on a block of wood about one inch wide on the outside of the gunwale. I wish they were about two inches higher or the seat was about two inches lower. But for my wife the position is perfect. With me, my hands hit my knees when I am extending my arms (the oars are tilted up out of the water on this part of the stroke)

By the way, I just bought some new sockets that have a plastic or teflon insert, and these are the smoothest, quietest oar sockets I have ever had. My old ones had no inserts and the oar locks were kind of loose in them and popped out too easily, and rattled when using a small outboard.

 

More on oar length here http://www.shawandtenney.com/wooden-rowing-oars.htm

 

Skid; That's a tiny boat. Can you post a picture. Please do so if you can.

Your question about seat placement is important. It should be placed so that the boat is almost level when you sit in it. On such a small boat, that location (fore and aft) will be very important. Maybe you could rig a seat cleat so that the seat is movable until you find the right place for it. A few inches this way or that will matter.