Groove for Garboard strake

[acaron41120]

i have several wood model ship building books and have read those and read many on-line sites on the subject of cutting the groove in the keel for the garboard strake. What I find interesting is that cutting the groove in the keel is never mentioned in the kit model instructions. Which leads me to my question. Are the kit instructions taking for granted that everyone knows to cut the groove for the garboard strake or is that groove really unnecessary? Just wondering is all. I’ve never cut this groove in my model ships until my current build, Mayflower and have had no problems.

[allanyed]

Allen,

The groove is called a rabbet which I believe comes from the French word rabbat, meaning a recess and is a dynamic landing space for the edge of the garboard.  The rabbet goes from the top of the stem, down to the keel, aft to the stern post, then up to the wing transom.  Along the keel it is shaped in conjunction with the frames (or bulkheads) so the garboard strake fits neatly and securely.  The sketch below shows where it is very dynamic aft to accept the garboard as it goes from near horizontal midships to near vertical.

 

Practically speaking, you can install the garboard any way you like and it may look OK if done with care.   Look at your models and compare to models with a rabbet.  There are MANY photos of models at the RMG Collections site that you can study.

 

Pic below may be of some help. The second pic is a contemporary model that happens to have drop strake.  Note how, every strake tapers and other than the drop strake ends at the rabbet.

 

Allan

 

 

 

 

Edited July 21, 2022 by allanyed

[mtaylor]

I believe that POB kits get around this by selecting their false keel, keel pieces,  bow, and stern thickness along with the planking wood thickness such that rabbet is ignored to keep it simple to produce the kit and also build it.  

[Gregory]

The only thing you might watch for is the bearding area, and not carry the first planking beyond the bearding line, as it might be difficult if not impossible to get the second planking flush with the stern post and keel in that area.

[Jaager]

A floating vessel is like a living thing.  It is subject to many forces that cause the structural parts to flex, rack, and twist.  The keel does not always move the same as the bottom planking.  The seam where the garboard plank meets the keel needs to be as strong and leak proof as can be had.  

A static model is only subject to micro movements.  As long as the joint of the garboard with keel looks as though it is secure and water tight, it does not need to be a rabbet.   

The rabbet is a "thing" with scratch builders whose object is to mimic actual practice.  With a POB or full planked solid or POF hull, a straight butt joint runs the danger of separating with an unsightly gap if time and temp and humidity flux acts in that way.  "You pays your money and takes your chances."

 

A hint for the garboard:  the edge that meets the keel, stem and sternpost is a straight line from tip to tip.  Any wood removal is done on the outer edge.  Removing wood from the edge where it curves up the stem gives it the wrong shape.  It really messes up the rest of the bow planking. 

[druxey]

Do read the planking articles posted on this site!

[catopower]

Hi Allen, I agree with Mark's explanation.

 

Many kit manufacturers have some way of getting around the need for cutting the rabbet for the garboard planks, which is probably why you've never really had to worry about it in your prior builds. I too have seldom found it necessary to cut a rabbet for the garboard strake for a kit model.