Skeg and Rolocks

Couple (more) dumb newbie questions, if someone doesn't mind answering them.

I'm building a 'Summer Breeze' - 12ft sailing skiff.
Mine has changed a little from David Beedes design - mostly because I'm adding a centreboard.

First Question: What does a skeg do?
The plans include one, but things I have read elsewhere give the impression that it is mostly a benefit for rowning and doesn't help sailing much? - I intend to do no rowing at all (wind permitting), or even less.

Second Question: Does it matter where the rolocks go.
If I've gotta have them they may as well go in the right place - if there is one.
I know a lee board has to go at the widest part of the boat, a cenreboard/leeboard has to be aligned with the sails COE - is there a right and wrong place for the oars/rolocks??

 

It helps tracking, and if deep enough it also protects the rudder. Not to mention it might strengthen the bottom.

Yes, it does matter where the oar locks go.
Take a look here:

http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=00AvXF

It's important you place them in relation to the seat, not the boat, all other things being equal and within reason. To have them fit both would be best, but don't place them somewhere awkward in relation to yourself while seated merely because it will fit some rule of thumb about boats. Because if you do,you will certainly never row, being uncomfortable, resulting in backpains etc.

You have to think weight distribution of yourself into that context. You don't want your only rowing seat to be placed in the front of the boat.

Take a look at these boats:

http://www.adirondack-guide-boat.com/vermontfishingdory.html

Most have two sets of oar locks – one being aft of the middle if rowed alone, and the other set is used if more than one is in the boat.

To be even less precise, it also matters how long legs, or rather how long of an upper body and arms you have to be perfect in relation to you personally. One placement might be perfect for your neighbour, but a little too close or far away from you. Your weight or lack thereof might also be in the equation.

What I am saying is: Look at other boats, and then try to do the same on yours - sit in the boat, see if the weigt distribution is okay, lay the oars and see if you get it right, and when pretty sure, add the oar locks.

 

oarlock placement

Yet another item to throw into the mix on oarlock placement is the boats beam. you will find that a beamier boat will require you to place the locks further away from the thwart. This is necessary to give you enough room to be able to get a long enough pull on the oar handles to move the blades far enough to provide efficient power. On my competition double; our locks are at 18" and 21" aft of the back of the thwart. The difference is due to differing body size and style of rowing. boat beam at the locks on that boat is 51". It's probably not necessary to spread things that far; as we are going for maximum power. Just don't crowd yourself too much. We have found that the old "chestnut" rules of thumb for oarlock placement don't take into account beam amd physical size of the oarsman.

 

Might as well throw in my 2c. If you want a tighter turning circle under sail (or quick tacking in narrow channels) leave the skeg off. If you want the boat to track well on longer legs leave it on. This is assuming rowing isn't a priority. You can always use the rudder to make the boat track under oars.
As for rowlock placement, like the others said it should be in relation to the seating. Presumably this skiff already has a thwart on the plans. I find about 650-700 mm from the centre of the thwart works well. Go the lower figure if you're average height or less, the upper if you're taller.

 

Leave the skeg on and as designed (profile) as it's very likely it is accounting for a substantial amount of lateral area. Removing it may cause enough of a change to dramatically affect the balance of CE over CLP. Your centerboard also has to be positioned accurately, preferably with the same amount of lead developed into the daggerboard placement.

 

Here's a link to plans for the boat in question: http://simplicityboats.com/summerbreezetemp.html

The skeg is very small and would make little or no difference to the sailing qualities.

 

Thanks again for the input.
I mostly relied in info picked up from Jim Michelak's news letters to work out the positioning of the centreboard/mast, so hopefully I got that right. It kind of dictates the best (easiest) position for the seat. I think sitting in it and and positioning the oar locks relative to the seat by trial and error sounds a reasonable approach. At the end of the day I'll only use them when I run out of wind )

As to the skeg, I will be in narrowish channels (Pummicestone Passage, Qld) but the prime purpose of this boat is to learn to sail, so stability is probably more important than speed or manouverablity. There will probably only ever be me in the boat. Which I think means leave the skeg in?

 

You could also fit a removable rowing seat in order to get a better position when rowing. That seems like a better solution than placing the seat in an awkward position because it interfers with the sailing.

The thing is, if it's crap to row, you won't. And then your statement, that it will be used seldomly is a self-fulfilling prophecy.

I'd personally leave the skeg in. No sense in removing it. If the designer didn't think it was important in some form or fashion, he properly wouldn't have included it. I don't think you should handicap the boat on purpose.