|Nov 20, 2006, 12:27 PM|
Plenty of hard tack and rum to go round thar mate. Of course a little extra protein comes with that hard tack too. Just be sure you get the fat weevils...the skinny ones get stuck in between the missing teeth...and it looks a little strange when ya smile with that weevil wiggling its head around at everyone...lol
|Dec 07, 2006, 10:01 AM|
Effect of adding buoyancy to keel?
I was reading another thread and part of the discussion was the "Effect of adding buoyancy to keel". It was suggested that by making the keel more buoyant, the boat would tend to tilt more, if it already had a tilt.
I had never considered that, and now am not sure if I want to plug my keel ballast holes with styro, wood or at all. Even if I tape over them (to reduce drag) I would have air pockets (I could poke a pin hole to allow them to fill with water, but that would not help make the ship ride higher in the water, which is what I am also looking to do).
My question is...by doing anything to add buoyancy to the keel ballast such as filling the 1/2" holes I drilled in it with a buoyant material, would my ship tend to try to roll over? My first thought is yes?
Any experience or expertise here is most definitely solicited.
"Always choose the lesser of the two weevils!"
|Dec 07, 2006, 12:10 PM|
I decided to ask the expert himself, and as per usual received a very professional and timely response:
By reducing the weight (or adding buoyancy, which has a similar effect) of the keel or shortening its depth you will of course reduce the force needed to heel the ship. But what you are doing will not be enough for you to sense any difference whatsoever in heeling in the water (unless you were measuring things very carefully in a test tank!).
Thirty 1/2" holes through an average keel thickness of 0.65" will decrease the keel weight by 1.57 lbs. Not filling them with wood will effectively reduce the volume of the ship by 3.85 cu in. This counteracts the weight reduction by 2.5%, a trifling amount. However filling them with wood restores the laminar flow of water along your keel and rudder which should be quite significant.
I did these calculations quickly and haven't checked them, but they sound about right. Certainly none of this will have an appreciable effect on heeling.
There is no special significance in the fact that the wood plugs you add are buoyant - the forces and densities are averaged out over the entire element - your actions will be like reducing the density of the lead the keel was made from from 11.37 g/cc to 10.7 g/cc, still heavy and effective!
Thanks once again goes out to Philip Roberts for such a wonderful product and caring enough to help us with our endless questions. 3 cheers!
"Weevils...the breakfast of iron men sailing wooden ships!"
|Feb 08, 2007, 07:35 AM|
I could use some help on this one guys.
I'm ready to add some detail to the tiller. The original setup had a working tiller that was connected to the rudder. I decided to add the crew and the addition of a helmsman forced me to disconnect the tiller and glue it down. That being done, I think the addition of the tiller tackle is something that would help the looks and not add any weight.
My problem is... my lack of detailed information on how I should rig it. I have found one photo (below) but it is rather unclear and I am at a loss.
Anyone have a detailed pic or drawing and or link?
oh and yes...Dan...my name is Robert...lol
"Weevils................the breakfast of iron men sailing wooden ships!"
|Feb 08, 2007, 11:31 AM|
Here's a diagram from Petrejus of the Irene tiller rigging. Also is a pic of a rigged wheel and tiller from this site: http://www.modellmarine.de/phpwebsit...N_position=9:9
The line is wound around the drum 5 times, and is stapled to the drum in the center.
|Feb 09, 2007, 07:16 AM|
Thanks Dan...that is an interesting site.
The Prince tiller is not connected to a wheel so the rigging is going to be a little different. Once again I have picked Philip's brain for some historical expertise and once again he has enlightened me with his vast knowledge on the subject. (Thanks Philip)
Attached is another photo of a modern schooner and Philip says this would be the way the Prince would have been rigged. He also says the rudder stock is a little far forward on the more modern ship and should be only 3" (full scale) forward of the front face on the Prince. He also says the one on the model is not correct.
My deck misalignment caused my rudder stock to end up in the front face too far aft. It was a lot of trouble drilling that thing out and making it work. But, now that I have a crew and dont have it swinging from side to side like it did when attached to the rudder, I will move the rudder stock out to its correct position and fill in, sand and paint the front face. I dont think I will put another hole in my deck like in the photo but try to give an illusion a hole for the rudder stock to come out of.
This is the way I picture the rigging:
1. Tie the line to the tiller handle (a 1/3 of the way back from the end),
2. Run it through a double block attached to the bulwark just above the waterway,
3. Run it back through a single block attached to the tiller handle, just forward of where we started on the handle,
4. Run it back through the double block again,
5. Then coil the rest on deck next to the double block.
Philip also gave me another interesting tid bit on the use of these things. He said the in time of battle the tiller was unshipped and an iron tiller bar was used below deck.
Seems I too have endless things yet to do on this model...but that is one reason these things are so great...we can just keep on changing them and making them better.
"Weevils........the breakfast of iron men sailing wooden ships!
|Jun 12, 2007, 10:39 AM|
Additional discussion about this ship and several other beautiful 1/24 scale SC&H square riggers can be found in this thread...
(Edited to link the 2 threads.)
"Weevils...the breakfast of iron men sailing wooden ships!"
|Jul 06, 2007, 08:19 AM|
Rescue of stranded sailing ships
Posted by Brooks on this thread and moved here.
You could predetermine the max wind your tug would be able to handle, in a manner similar to figuring out it's ability to haul the Schooner off the sandbank:
1. measure the bollard pull of the tug using a fisherman's scale.
2. measure the windage of the Schooner, ie it's pull on the fisherman's scale, when sitting at anchor at various wind speeds.
3. As long as the windage is less than the bollard pull, the tug should be able to handle the job.
The farther apart the 2 numbers are, the faster the tug will get the tug&schooner combo up to "hull" speed. The hull speed will be reached when the form drag of the 2 hulls plus the windage drag of the 2 boats equals the bollard pull. Once the the thrust and drag vectors are equal, no further acceleration is possible, for the mathematically inclined :-)
As you know, it takes very little force to move something floating in water. Even a pixy tug would be able to move your schooner in still air, provided you gave it enough time to accelerate the combo. The hull speed of the pixy tug combo would be less than that of your tug&schooner because the form drag and windage drag both increase with speed, and the equilibrium point would be lower for the pixy.
A long, slick hull like your schooner's should be towable with little force in still air, I would think. Anyone with a valuable sailboat like your's has an interest in rescue techniques. If you were to figure out the numbers and capability for tug and Schooner, I think we'd all be interested, particularly Phillip so he could put the info in his advertisements.
Even if you find that the tow ablity of your tug is limited to light airs, I would not be too discouraged. Your tug may still perform useful rescue service. For instance, if you lost RC control of the Schooner, you could still sail the Schooner back home by using the tug to turn the Schooner on course by pushing on it's bow. Depending on the sail configuration when the RC crapped out, you might have to wear ship, rather than tack, with the tug's assistance. And your zigzag upwind might not be composed of equal angle legs if your squares are set (since they'd be aback for one set of legs). But even a sawtooth recovery course taking lots of time might be preferable to having to chase the ship downwind to a lee shore.
While on the subject of rescue, may I suggest that you install a marker buoy on your Schooner, with a line long enough to reach the surface of whatever water body you are traversing. The buoy could be a freely detaching fitting of some sort, something you'd normally find on deck. The line needn't be strong enough to haul the ship back to the surface, just something strong enough to support a buoy to let you know where to dive to recover the ship. Accidents happen: I read of a guy whose schooner was run down by a paddle boat - it remained floating, fortunately, but if it had sunk, a marker buoy would have been comforting, I bet.
Yes...it would be interesting to know the amount of pull the schooner has and the tug has. I don’t think a fishing scale would be sensitive enough in the lower range needed to gage the force each exerts, at least none of the ones I have will work.
I did devise a marker buoy system for the Privateer Schooner Prince de Neufchatel…but never installed it. The reason being that the small lake I used to sail her in was drained and the only other place I sail her, due to lack adequate launch sites, is in a pond at the park. The pond is only 3 ft deep according to the engineer that built it, so theatrically if she goes down she should still have masts sticking out of the water. The biggest problem with the pond is NO shade trees and as you know…it gets very hot and humid here in Alabama. So…I choose not to sail her right now, opting to work on other boats and sail in another pond nearby that does have lots of shade but no place to launch deep drafted large ships. Another problem is the pond has an island that makes it possible to run aground and is inaccessible, as is one whole side of the pond due to a shallow weedy area. I don’t care to get in the water due to rather large Water Moccasins that I have observed in outings past. The ponds are no fishing, boating or swimming posted and I am the only one I have seen to use RC boats in them. I was told that someone with RC Nitro go fast boats tried to use the ponds, but got run off. They are loud and a problem for the wildlife. These ponds are in a park that contains the Alabama Shakespeare Theater and is one of Montgomery’s tourist attractions. Sooo…if I want to continue to use them, I need to be kind to the ponds and stay low profile with wind power and slow electric boats.
One other solution I thought of to rescue my ship is to attach a line to the tug, the other end in my hand and try to encircle the schooner (if it runs aground) release the line from the tug and pull the ship by hand off of the shoals. The line would need to have a small treble hook to snag the tow line as I cross back over it. I just need enough force to get the ship free again. It might work?
So…I feel like I will have several systems in place the next time I go sailing the schooner and not have to worry about the shoals any more.
For a look at my tug tow line release system, go to the thread posted above.
|Jul 06, 2007, 05:45 PM|
A low tension "fishing scale" could be made from a ruler and a rubberband. Attach the rubberband to the 0 end of the ruler, then run a line from the band to the boat. Measure the stretch of the rubber band = bollard pull or windage. If the band is too weak (tug pulls band to the end of the ruler), just doubleup the band. You could calibrate the band with a known weight, or just use the raw measurement eg. if 2oz lead pulls the band 3 inches, your scale calibrates at 1.5"/oz. For your own purposes, an uncalibrated inch measurement would suffice; the calibration would be more for reporting your results for others on the forum to consider for devising their own rescue setups.
Your long-line-to-boat-and-back-to-shore is an accepted rescue method for models. If the rescue line is long enough (think kite string), you can dispense with the fishhook: you hold one end of the string in your hand, while the tug travels around the Schooner (carrying the reel of string) and then travels back to shore. Pull both ends of the string to retrieve the Schooner. Or you could just hold the reel onshore, if the tug is strong enough to haul the 100yds or so of string out and back while dragging it through the water.
If your Schooner falls over when it hits the bottom, the masts might not stick up high enough to break the surface. One tip on marking the location of a sinking object: don't stare at the water bubbles, stare at the opposite shore, picking out a landmark. Drop a handkerchief where you are standing, then dash off 50yds down the shore and do the same (drop another shore mark where you stand for this 2nd line). This will give you a triangulation, details of which you should write down before attempting a rescue. It is very easy to forget just what marks you were looking at, in the stress of the moment, so write them down for safety.....been there, done that.
I once swam for a prop adapter that had fallen off my RC floatplane. It was October in Montana and the pond was very cold. I almost did not make it back to shore...hypothermia hits very fast in water, even if you are well blubbered as I am. The sunken object was only 20yds offshore, I thought, so I did not think of the danger. Before I even got half way there, I was wondering if this was stupid (it was). Pride drove me on. I could not have driven home in the state I was in when I did get back to shore. I spent the next half hour in my friend's hottub. Lucky.
|Jul 11, 2007, 11:48 AM|
I made a mistake in the above post concerning how to use a rubberband to measure bollard pull. I give the corrected method in a new Dock Talk thread "Measuring and increasing a tug's bollard pull."