Keel taper

[Redshirt]

Hi,

After reading both the Triton plans and Modelshipbuilders amazing Eagle practicum ( and the MA thesis on which it is based) i came to finaly realize that keels aren't uniformly thick but taper at the bow and stern. Since im a completel newbie when it comes to scratchbuilding im not quite certain on how to achieve this effect or if a tapered keel is even necessary/ desirable on a scale model.

Can you please give me some advise on that matter?

 

Thanks in advance,

Daniel

[druxey]

There has been much discussion on where the taper begins. In a large scale model it will be apparent if the keel is not tapered: the stern post will be too wide at the bottom, and the fore end of the gripe (lowest part of the stem timbers) will appear too 'fat'. I taper my models' keels starting where the cant frames  (those that are placed at varying angles to the keel) commence fore and aft. 

 

May I recommend you read some books on the ships of the era you are interested in?

[Redshirt]

Thanks for the quick answer. I have read a number of books, guides and shipplans for pof scratchbuilding yet non have so far mentioned the taper of a ship's keel. For example, I plan to build Victorine (once i have assembled the necessary tools) but Portia Takakjian's plans, while otherwise excelent, don't seem to give any information regarding that problem either. Now i wonder if i am missing something or if this detail is just usualy not included in sheer/half breath and deck plans and has to be found in secondary literature about the desired ship itself.

[druxey]

Most modern texts don't deal with this issue at all, and it is not well described in primary sources.

[allanyed]

Daniel,

I don't know if they are appropriate to the Eagle, but the scantlings in the 1719 Establishment, the 1788 Shipbuilder's Respository and David Steeles Elements of Naval Architecture all include the sided dimensions of the keel afore, midship and aft.  As Druxey mentions above, none of them indicate where the taper begins, and I agree with the assumption that it begins at the cant frames, but it is obvious from these dimensions, there definitely is a reduction in siding.

Allan

[trippwj]

While the following doesn't provide any guidance on where the tapering starts, here is an example of how the keel, stem and stern post for a US 44 gun frigate of 1794 were described -

Keel - sided 17inches stem and post 19 inches midships
Stem - in 2 pieces, sided 17 inches,
Stern post - 18 inches square at the head, sided 17 inches 3 1/2 feet below, etc.
Inner post - sided 20 to 24 inches at the head and 12 inches at the keel.

Keel of good sound white oak in 3 pieces. The middle piece to be not less than 80 feet if to be had. Scarphs not less than 12 feet to be kept clear of the main and fore steps sided in the midships 19 inches at the stem & post 17 inches and as deep as can be had. The scarphs all to be tabled and bolted with 5 bolts 1 1/8 inch diameter. False keel 6 inches thick but not to be put on until after the floor & keelson bolts are drove and riveted.

Stem in two pieces if to be had the lower one of good white oak sided 17 inches and moulded not less than 12 inches clear of the rabbet scarphs not less than 4 feet to be tabled and bolted with 3 bolts 1 1/8 inch diameter.

Stern post 18 inches square at the head sided 17 inches below by 3 ½ feet fore & aft including false posts and 10 inches thick on the aft side at the keel to be fitted for a crooked headed rudder.

Inner posts to be 12 inches for & aft to run from the transom to the keel to be of live oak sided at head from 20 to 24 inches and at keel 12 inches.

 

Wayne

Edited September 24, 2014 by trippwj

[Redshirt]

Thanks for the answers guys, they were definately helpful.

Now i know where to begin the taper and, judging from Eagle, the US 44 gun frigate and the Triton plans here, that the taper won't be much more than one or two milimetres at the stem and stern at the usual modelling scales. Even without definite informations for all ships, this will probably give adecent result.