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Anchor Hoy by Maurys - POF Harbor craft c. 1825 -- 1:48 - Finished


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Anchor Hoy / Water Tanker c. 1814 -1825 Designed and built by Francis Grice in the Norfolk Navy Yard.

Grice designed and built many ships for the US Navy and was appointed Chief Naval Constructor in 1847. He headed the Naval Construction Department until his death in 1859. Grice is among the few who have left tracings and papers describing work boats. They were preserved by the national government in the Office of Naval Records and Library and were subsequently transferred to the National Archives. They were reproduced in part in Grimwood's American Ship Models. Grant Walker at the Naval Academy Museum referred me to a source for the plans.

 

Anchor hoys were designed to carry and recover huge anchors and many had large water tanks to service ships in the harbors. This boat has a length between PP of 56' 9” and a breadth of 20'. At a scale of 1:48, overall length of a model (with spars) will be less than 24”. Some of the reasons for choosing this vessel were the sloop rig, double capstan and gearing system used to hoist the anchors, the running rigging of the shrouds and the shroud supports for the main mast supporting the weight of the anchors.

 

There is little known about the actual construction of these boats, so the frame and spacing is conjectural. After reviewing the series Shipyard and Service Craft: A Portfolio of Plans by Robert Cairo in the Nautical Research Journal from June, 1976 through September. 1979 (eight installments), one can extrapolate many dimensions of various parts and Scantlings of Royal Navy Ships 1719 – 1805 by Allan Yedlinsky provided many particulars even though it does not directly address work boats such as this anchor hoy. While the water tank can be seen in the profile drawing, there is nothing that indicates its width.

 

The plans I acquired were conjectural so I used them along with copies of the original Grice drawings to start to loft a more complete set for the 1:48 scale I have chosen to use. This will be a plank on frame model with partial planking to expose the details of the framing and the gears attached to the capstans. That process involves using a CAD program. While I have drawn house and furniture plans, I have never tackled ship plans before. There is an article on this site by Wayne Kempson titled Drafting Ship Plans in CAD. http://modelshipworldforum.com/ship-model-plans-and-research.php  While I am only partially into the lofting process, that report has been invaluable. The skills I've acquired on several POF models I've build over the years and particularly the recently completed Echo Section from Admiralty Models have emboldened me to take on this new challenge.

 

Pictures of the Grice drawings from the National Archives follow: 

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Since the weather was so nice yesterday, I spent some time in the garage (shop) making the building board and gantry (mostly per Ed Tosti's plans in his Naiad book).   The paper plan shown on the board is preliminary, just to see how things lined up.  I'm a long way from getting the frame layout finalized in CAD.  With the supports on the underside raising the board about 2 1/2", the working height on my work table seem awkward (too high).  I may have to build another table to hold the building board...oh well.

Maury

 

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Lofting:  After several practice runs the process is coming together...slowly.  I'm following "Drafting Ship Plans in CAD" by Wayne Kempson (WRKempson on this forum).  I've traced the original drawings by Grice as I think that is more reliable than the nice set of plans that were provided to me (in theory lofted from the same drawings).  Everything has been re-scaled to "full size".  The profile, body and half breadth have all been synchronized to keel and mid-lines and the process of projecting waterlines to the half breadth is underway.  Pause...Look at the two halves of the plan below. The upper half shows the waterlines as traced from the plan sheet (drawn in 1997??).  The lower half show the waterlines as projected from the body plan per the instructions.  There is quite a divergence at the lowest (inner most) waterline.  If the lofting process is to be trusted, I think I have to go with the lines I lofted and delete the traced lines.  Anyone with lofting experience please feel free to comment.

Maury

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I go through this same process with every boat I build.  I have yet to see a printed set of lines that are correct in all three orientations.  Keep on with the instructions.  You will have to adjust some lines to get things to line up correctly but eventually everything will line up and you will have a correct set of lines.  It all takes time and work.

 

Bob

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The left set fair with the station lines.  No diagonals avail and I don't know how to introduce them.  Could the inner most line on the right half be a buttock line?  Notice how the WLs on the right (traced from old plan) meet the keel much farther forward than the ones I lofted (on the left).

M

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From a quick glance at the original plan, it seems to me the waterlines you have drawn (on the left) are misplaced.  It is not apparent why this is, but I think I would draw another set.  If the second set comes out like your first lofting, then we are in trouble.  I suspect a second effort might come closer to the original, however.  Again, a quick glance says to me that something has been missed along the way.

 

Diagonals can be thought of as a cross between buttock and water lines.  Draw a diagonal line on the body plan.  This is normally drawn through the turn of the bilge.  The angle is somewhat arbitrary.  Anyway, draw a diagonal line on the body plan where it will be a straight line.  Then project this line to the half breadth plan with the same procedure as projecting a water line.  This gives you the look of the diagonal as if looking at it from above.  It will be a curved line, but will not match the waterlines because it isn't one.  Then project the diagonal line from the body plan to the sheer plan using the same procedure as you do for a buttock line.  This will result in a curved line that does not match the buttock lines because, well, it isn't one.  Then check for fairness on these two curved lines.  If you have done your station lines correctly the curved diagonal lines will be fair.

 

Employing multiple diagonal lines offers multiple checks on the fairness of the hull.

 

This is one reason for lofting or laying off the lines on the floor.

 

Wayne

 

PS on further reflection, your lines seem to treat the stern post as if it were perfectly vertical rather than angled.  Is this so?

 

PPS an image of your body plan (station lines with the waterlines) might help analyze what is going on.

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Thanks for the input and help.  The stern post is off-set by about 3.5 degrees.  The body and all three plans attached.  Sorry about the orientation on the first one.   Construction lines were run from body water line / section intersections to the half breadth station lines and those intersections were plotted.   Everything is square and aligned...distortion from camera.

Maury

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Druxey, The smooth blend to the deadwood was what I was hoping for.  Instructions say to start where the horiz. Construction line from the profile rabbet lines up on the half breadth and then connect the dots as you move from one waterline / station line /  intersection to the next.  Clearly I'm doing something wrong in the aft area.  Wayne, the body plan matches the original scaled and leveled picture  (traced line for line).  I've done a screen grab and got a cleaner but smaller picture.  Maybe it should start where the half frame intersects the deadwood rather than the rabbet.  More playing with it tonight.

Thanks for all the comments.

Maury

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I think I found my misteps.  The halfbreadth was erased and started again.  I tried to work backwards from the traced lines on the right side with vertical construction lines up to the body plan to see where the WLs began and ended.  This time, on the halfbreadth, I started the lowest aft waterline from a point projected from the bearding line on the (vertical) profile.  While the new lofted WL (on the left) is a bit wider than the traced line (on the right) amidships, the line does blend into the deadwood smoothly.

Thanks for the comments and tips.

Maury

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I spent many hours working with TurboCAD transferring, projecting and cleaning up the lines.  They look pretty good.   I have saved a separate copy of just the keel plan and the problem I'm having is determining at what height the Wing transom should be.  My best guess is at the top of the deck beam level, and resting on top of the inner sternpost.  Any thoughts?  Thanks,

Maury

 

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I would say that he upper face of the wing transom at the post should be at the base of the lower counter, that is, at the top of the stern post rabbet.  In addition to supporting the stern, it beds the ends of the fore and aft hull planking and marks the beginning of the athwartship counter planking above.  This planking transition is usually covered by a tuck rail.

 

Ed

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A lot of back and forth regarding the height of the wing transom (and hence top of the inner stern post).  There is nothing definite I can find so with the helpful comments of a few and some more research, I've decided to place it with the bottom just below the transition from counter to transom.  That's where the fore & aft planking changes to athwartship on the counter so it will provide support in three planes.

  The keel is 12" tall, the rising wood another 12" and the Keelson will be 12".  Frames are 6" (paired to make them 12" sided).  When I get tired of doing the computer work, I've gone into the shop and built some mini clamps (per Ed Tosti's plans).  Second Mate thinks they're "cute".

Maury

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Thanks again for the comments and all the "likes".  I started on the frame lofting to get a sense of the procedures.  Instructions were followed from Lofting Ship Plans, aided by the comments in Ed Tosti's  Young America vol. I using a pin alignment system.  A few mistakes and lessons learned along the way in dealing with the parts of the frames.  A point here is that once the parts are separated, you can't fix something on a futtock-- like pin alignment. You have to discard the part, fix the item on the full frame and take it apart again.  I'm not going to loft the beveled frame sides at this stage.  Most of the frames are very close to DF until you get to the foremost and aft most frames.   The dead flat frame and parts seem finished.  If anyone notices a fatal flaw along the way, please "speak now or ....."

Maury

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