Model Ship Builder :: Forums :: Build Logs :: POF Build Logs 

<< Previous thread  Next thread >> 
H.M.S. Ontario 
Go to page 1 2 3 ... 11 12 13  
Moderators: Winston, aew, bikepunk

Author  Post  
dave1254 
 
Registered Member #2647 Joined: Fri May 25 2012, 08:08pmPosts: 450  I will be starting off this POF model, by laying down the foundation first. By that I mean, the calculations to determine actual sizes of members etc. that the naval architects at the time used. eg. Deanne, Steele, etc. The other information gathered along the way that helps define the actual drawing used for construction. eg. Admiralty drawings from Marine archives in England, Articles from Charles Davis etc. It must be remembered at the time the ship was first conceived and built, American and Canadian shipbuilding was under the influence of British naval architecture. A lot of the gentlemen who emigrated to both countries were trained in Britain. So their base knowledge of ship construction was British. It's not to say they did not add personal touches to their designs. That is what evolution of the design is all about. The Americans even set forth a book of rules, per say, that laid down how particular parts of the ship were made and what materials. A guide line. So enough of this, I could have opened up a big can of worms here, that could lead to major discussions. The purpose is the ship design. When I have enough calculations I will post and the matching drawing in CAD. Helping to prove that the Admiralty drawings are correct and possibly help clear up, for me, how some of the members are made and why. Dave  
Back to top   
knotian 
 
Registered Member #308 Joined: Fri Sep 18 2009, 10:48pmPosts: 92  Dave  I will be following your efforts with great interest. Ed  
Back to top   
dave1254 
 
Registered Member #2647 Joined: Fri May 25 2012, 08:08pmPosts: 450  What we know about the H.M.S. Ontario Length of lower deck  80' Length of keel for Tonnage 62' Extreme Breadth 25' Depth in Hold 9' Breadthen in Tonnes 226 tonnes Terminology needed to understand old english wording Besides thous and arts etc words like : Sided  the dimension of a scantling taken as depth Moulded the dimension of a scantling taken as width Scantling is all timber or pieces that are part of the makeup of a ship I will get into other definitions as they arise. Moulded Breadth Extreme Breadth 2x the Bottom thickmess = 25 2x3" = 24.5' Bottom planks ( not Garboard) = .0185 of the half Extreme Breadth = .0185 ( 25) = .232 ' which is approx 3" Keel as by definition shall be sided 1/2" for every foot of extreme breadth = 1/2 ( 25) = 12.5" Deanne states in his works that the sided dimension also includes the false keel . This is a normal practice in all shipbuilding of the time. But if you look on the draughts you will see no false keel. I don't know if Coleman didn't include it in the drawings but it is not assumed to be included. Most draughts that I have seen include it. Also Deanne states that the keel was basically square. Moulded dimension = 12" True length according to Steel: Measured from the back of the stern post at the level of the rabbitt , along the rabbitt to the perpendicular under the bowsprit on the level of the Hauseholes minus 3/5ths of the Breadth must equal the true length We need a dimension here which is called the Rake of the Stern by definirion is 1", 2" to every 6 feet of the length of the post. I have since upgraded this formula. It is more accurate. Length of stern post = Trim ( 1/50th' per1'Length of ship) + depth of hold + Aft deck rising ( 2"per10' of L) + height between decks + height of wing transom = 1.64' + 9' + 1.8' + 6' + 1.13' = 19.57' Rake of the Stern post = 1" to every 6' of 19.57'' = 3.26' = 63.3' I have also changed the length of keel formula. This L = 9/10 of length of ship = 9/10 x 80' = 72' Now we can turn our attention to the Load Water Line or L.W.L. Which by definition is 3/5ths of the Top Limber Line or T.L.L. which is for two decks or under 1/5th of the Length = 1/5 (80) = 16' therefore the L.W.L. is 3/5ths (16') this is at midships position = 9.6' The height of the L.W.L. at the perpendicular of the stern is the 9.6' + the sheer of the forward deck or forward rise of the deck. Which by definition (Steel) is 2 1/4" for every 10' in length. = 9.6' + 1.5' = 11.1' [ Edited Fri Jul 06 2012, 06:28pm ]  
Back to top   
dave1254 
 
Registered Member #2647 Joined: Fri May 25 2012, 08:08pmPosts: 450  here is the first cad image of using the data to draw  
Back to top   
GMintz 
 
Registered Member #197 Joined: Thu Aug 06 2009, 11:31amPosts: 25  Looking forward to your posts. Greg  
Back to top   
daves 
 
Registered Member #105 Joined: Wed Jul 15 2009, 12:01pmPosts: 2624  wrote ... It must be remembered at the time the ship was first conceived and built, American and Canadian shipbuilding was under the influence of British naval architecture. A lot of the gentlemen who emigrated to both countries were trained in Britain. So their base knowledge of ship construction was British. It's not to say they did not add personal touches to their designs. That is what evolution of the design is all about.
The Americans even set forth a book of rules, per say, that laid down how particular parts of the ship were made and what materials. A guide line.
So enough of this, I could have opened up a big can of worms here, that could lead to major discussions.
The purpose is the ship design.
i don't think this opens the can of worms but it does make for a good discussion. there were 2 major British shipyards on the lakes at the time Amherstburg and Kingston. Looking at the city records of Amherstburg over 50% of the population of the town were French the rest was a mixture of German, and America indians with a few British. Most of the people in town were employed in the Kings naval yard which were French carpenters the man incharge of the yard was Irish. Same at Kingston the yard employed French shipwrights from Quebec. The ship wrecks show ships built at these yards were not British design but French design. The General Hunter, Psyche, Princess charlotte, St Lawrence, prince Regient were all French design and built. All the admiralty plans were drawn "as built" and were not built from British designs. you have to remember the French established the region and shipyards over a 100 years before the British got to the lakes. The first French shipwrights were building ships in 1679 on the lakes. Records did say the British commented the French were better ship builders for ships on the lakes because they were at it much longer. [ Edited Thu Jun 07 2012, 02:20pm ]  
Back to top   
dave1254 
 
Registered Member #2647 Joined: Fri May 25 2012, 08:08pmPosts: 450  You are absolutely correct. The further I dig into the actual drawing of the ship, I was finding that formulas were closer to continental design factors. Some French and some Dutch so far. The figures are coming out real close to the measured Draughts. Starting with Deanne and Steel, assumption I found errors that were not jiving to the Draughts. Once I figured that the formulas were closer to europe I am proceeding faster now but still cautiously. Thanks for confirming this.  
Back to top   
dave1254 
 
Registered Member #2647 Joined: Fri May 25 2012, 08:08pmPosts: 450  What I have done next, was to check my results with the actual Draughts. I am wrong on a couple of places. Or should I say that the formulas I used were wrong. The Keel length formula is wrong. I instead used Van Yk a Dutch shipwright, and determined that the length of keel is = 9/10 the length of the lower dec . He uses the length marked from the outside of the stem and the stern post at the level of the lower deck.. Since the perpendiculars are set up to the outside of the stem and the inside of the sternpost. We can add approx. 1' to the length of 80’. So therefore the equation now works out to 9/10 of 81' or 72.9' This coincides approx. with the draughts. The scarph is next. The minimum of any ends of the scraph is 6" and a length of 4' bolted at 6" intervals; according to Steel. The rake of the sternpost is right, I just put it in the wrong place. The rake measures from the back of the sternpost at the keel height to the perpendicular at the height of the stern post. This puts the intersection of the sternpost perpendicular with the lower deck at the front or inside of the sternpost. So now I turn my attention to the stem post. I have to determine my height first. If you notice on the draughts, the stem post almost is straight at a point at the crutch of the curve of the figurehead knee. When I use the formulas to calculate the height of the stem they all seem to point to this area. Therefore I will use this as my base point Therefore stem height = to 11/60 of the length. The length determined from the above calculations as 81' therefore the height is 14.85'. Now I must determine the intersection points to draw the curves of the stem. ( apron, rabbitt and outside of stem) all related to the keel and scarph. 1st. I extended the line at the end of the keel 6" up ( the beginning of the scarph) past the perpendicular. 2nd I made another perpendicular 1.15' past the first one. This is the width of the stem. 3rd. I made another line parallel to the bottom of the keel at the top of the keel, extended past the perpendiculars 4th. From the intersection of the 2 lines of the perpendiculars and the bottom of the keel draw a line the height of the stem. 5th. Measure the distance from the intersection from the stem height and the first perpendicular to the height of the scarph at the top of the keel. 13.85' .Draw an arc from the top of the stem at the first perpendicular into the hull. Now draw an arc from the intersection at the top of the keel and the scarph until the 2 lines x. From this intersection draw an arc of 13.85'. 6th. Add .25' to 13.85' and draw another line from this intersection. This will give you the rabbitt. 7th Now measure down from the height of the stem to the line at the keel from the start of the Scarph. This along the outside perpendicular. 14.35' Draw an arc into the hull. 8th. Now draw an arc from the top of the scarph at the keel the same distance 14.35' 9th. At the intersection draw the arc from the top of the scarph at the front of the keel to the height of the stem. This is the outside of the stem. You will notice it does appear right. We are not finished. 10th. Draw a line from the intersection of the lines of the beginning of the scarph front of the keel to the intersection of the lines we just finished drawing. 14.35' ones. Now draw a perpendicular line from the top of the scarph at the top of the keel, until it intersects this line. 11th. From this intersection draw an arc 8.33' and then add .25 for the rabbitt and draw another arc. Then draw another arc 9.69' and this is for the front of the stem 12th. Trim all extraneous lines for your finished shape of the stem. 13th. You will notice that the lines to the top of the stem at the 14.35' mark extend past the 2 perpendiculars. The beauty of autocad is you can trim where the lines meet. This just so happens to be the height of the lower deck at the stem. 12.22' If you look at the draughts you will notice that the stem is so close to being vertical here. If we had left the lines of the stem curved at the perpendiculars the stem would have been raked back to the stern and this is a no no. I am going to leave the apron for now.  
Back to top   
knotian 
 
Registered Member #308 Joined: Fri Sep 18 2009, 10:48pmPosts: 92  Daves In your post "The Americans even set forth a book of rules, per say, that laid down how particular parts of the ship were made and what materials." To what are you referring? Ed  
Back to top   
dave1254 
 
Registered Member #2647 Joined: Fri May 25 2012, 08:08pmPosts: 450  here are the cad drawings  
Back to top   
Go to page 1 2 3 ... 11 12 13  