Shape of Rabbet on False Keel

[Bob in MO]

I'm starting on my first model the, MS 18th Century Long Boat 1:24.

After reading through the instructions and looking at the drawings, I'm a little confused on what the shape of the rabbit should be on the false keel. Please see the attachment. Which of these is the correct shape, A or B?

 

Thanks

 

[Thunder]

Hi, both may be right depending on where on the hull the profile is for. Possibly A where the planks terminate at the stem and B along the lower keel.

[Matrim]

The angle does change as it moves. I tend to simplify buy having 3 angle cutters to do the line dependant on where it is.

[allanyed]

As mentioned above, the angle changes as it should be close to the angle of the frame (or bulkhead) where it meets the keel.   Perhaps the below sketch

will help you a bit

Allan

 

     

 

[wefalck]

One should perhaps also mention that the included angle should always be more or less 90° (as per your sketch A above). However, the angle by which this corner intersects with the keel/false keel changes (as mentioned by others already) along the keel-stem/stern assemply as the angle by which the planks intersect with these changes.

 

The best thing would be to take a 'spline', i.e. a thin straight plank with clean sides at right angles and have it aligned to the outside line of the rabbet as per your drawings. This allows you to estimate how much wood you need to cut away for the inside line so that the spline butts nicely against the rabbet.

[Bob in MO]

Thanks, I think the light bulb just came on. 

[Jonesey]

So if you're double planking, presumably you would need to cut away enough material from the keel to accommodate both layers yes?

[wefalck]

Actually not. The under-planking is just there to allow better fairing of the real planking. So, the rabbet should be cut, after the under-planking is on.

[bruce d]

8 minutes ago, wefalck said:

Actually not. The under-planking is just there to allow better fairing of the real planking. So, the rabbet should be cut, after the under-planking is on.

That is the way I have drawn my plans without actually stopping to think about it. Thanks for the confirmation.

[ccoyle]

Forgive me, I couldn't help myself.

 

This is a wooden rabbet...

 

...and this is a wooden rabbit.

 

Subtle difference. 😉

[bruce d]

23 minutes ago, ccoyle said:

Subtle difference. 

Groan.

[Gregory]

The angle of the rabbet may not be as critical in modeling as it is in actual ship building..

Once a plank is in place, the angle is not apparent..

 

I prefer the easy way out of attaching a small strip along the false keel, which I learned from Chuck's models.

 

[wefalck]

Building up the keel and stem-/stern-posts this way certainly is an option, particularly, when you paint the model afterwards. If you opt for an 'artisanal' kind of model that shows your skill at woodworking, you probably would need to go for cutting a real rabbet into massive wood.

 

BTW, I did not understand the above picture: the actual keel and the posts should be wider than the 'false' keel plate in order to provide a step against which the planks can land.

[Jonesey]

4 hours ago, wefalck said:

Actually not. The under-planking is just there to allow better fairing of the real planking. So, the rabbet should be cut, after the under-planking is on.

Thank you.

 

That makes sense!

[Gregory]

17 minutes ago, wefalck said:

BTW, I did not understand the above picture: the actual keel and the posts should be wider than the 'false' keel plate in order to provide a step against which the planks can land.

As an example, say the false keel, stem and stern post , etc. are 3/16" thick.  The strip would then be 1/16" and centered on the edge of the false keel, leaving a groove ( rabbet ) of 1/16" on each side for fixing the planks.  

Here are more images from one of Chuck's builds that illustrates this better..

 

 

 

Of course, the bearding line and tapering the false keel to meet the stern post would be similar to the usual practice.

Edited July 30, 2019 by Gregory

[wefalck]

That makes sense now  👍

 

Edited July 30, 2019 by wefalck

[Mark P]

Evening Bob;

 

Speaking of 'Rabbets' vs 'Rabbits', and other terminology, the keel you show is actually the main keel, not the false keel.

 

The false keel is a thinner strip fixed to the underside of the keel, designed to break away in the event of the ship grounding accidentally, thereby avoiding excessive stresses being transferred to the main structure, and giving the vessel more chance of sailing free. This false keel is shown in Alan's post above (no 4) showing a ship's keel. I am not aware of longboats ever being fitted with a false keel.

 

It is fair to say though, re 'rabbits', that the word is frequently spelt this way in contemporary contracts describing ship-building. The only version I have never seen amongst the many spellings, is the modern word 'rebate'.

 

All the best,

 

Mark P

[Gregory]

Exploring my notes led to page 1 of the Syren instructions from ModelExpo

 

Syren Instructions authored by Chuck Passaro.

 

It has some excellent details about the rabbeting strip, and also the actual " false Keel " that Mark gave a good description of..

A lot of kits do not include that feature which probably existed on 99% of these wooden ships.

Edited July 31, 2019 by Gregory