Noodlin'...just a rough sketch

[Lewisboats]

Playin' with this very Bolger-esque type cruisin' shallow water boat hull design. It has a box keel and 7 ft headroom in the cabin along the 3 ft wide (center) box keel centerline. It is 30 ft long with an 8 ft beam and it should be trailerable. Lookin at 1/2" and 3/4" ply for construction, it drafts 33" @ 7 tons total displacement (salt). I was thinkin of a Gaff Ketch rig of about 350 sq ft with a very forward formast...similar to a Cat Ketch. This is to keep the cabin open. I was wondering if there are any thoughts on the thing...constructive critique so to speak



http://angelfire.com/ego/lewisboatworks/Stuff/Noodle.JPG

[P.L.Lenihan]

Looks very interesting! However,if I may, I would propose extending the boxkeel all the way up to the stem for maximum bouyancy where it will help the most toward helping the bow rise to/over the waves instead of punching through them. I hope you do not take this badly! Being a gaff -ketch with the mainmast well forward to clear the cabin, the added bouyancy of the box keel will help with the added weight of the forward placed mast.

Looking forward to your interior arrangement plan :-)


Peter

[Lewisboats]

I had thought of socketing the mast down thru the cabin and butting into the forward corner of the box keel, stepping it as low as possible in the hull. The design is inherently a water splitter rather than something that rides on the water and pounds. As the weight is rather optimistically heavy I would think that the forward buoyancy is correctly placed and with a small engine in the Box keel somewhat aft of center...fairly well balanced. I would expect having to add about 3 tons of lead (A shoe on the bottom of the box keel) and a bunch of interior ballast to get the proper displacement. The wood alone would probably only run 2500 lbs or so...if that. The problem with this is getting it heavy enough rather than the reverse.

Steve

[P.L.Lenihan]

Steve,

I understand your point. However, if I have understood Bolgers itterations regarding sharpie hulls and boxkeels, they work best when the curve of the hull sides ,in plan view, matches the rocker. Similarly, the box keel,particularly the forward half, benefits from more or less mirroring the hull it is attached to. Bolger suggests this to equalize the preasure of the water flowing around these shapes and to minimize eddies created from water flowing almost laterally from the high preasure side to the low preasure side, instead of the nice balanced slicing of the water we see in our minds eye,but which in fact does not occur if the hull sides and bottom are not perfectly matched in their curves.
He has several dozen designs which have put this to the test, if I recall correctly.
I am no designer and can only parrot what I have read.Nevertheless, I,for one, do like the look of your design proposal.....except fot the way the boxkeel is abbreviated back from the stem :-) and I hope you get lots of positive feedback to further encourage you in completing this design.
Now,hows' about the interior layout :-)

Peter

[Lewisboats]

I may have erred on the heavy side when I said this might be trailerable... I don't know many civilan vehicles that can tow 16000 lbs... An F450 perhaps...maybe a F550. Suffice it to say it is a bit too heavy to tow with your typical rig. I guess I will have to downgrade it to a manageable size.

[Lewisboats]

I'll play with what you suggest and see if I like it.

Steve

[paladin]

you could reduce wetted area, simplify construction and maybe a better sailing vessel by just making it a V bottomed single chine construction with a narrow "box" at the keel line to allow the engine and batteries in the box with the ballast...but what do I know......:D

[Lewisboats]

Now,hows' about the interior layout :-)

what would be your thoughts????

Steve

[Lewisboats]

you could reduce wetted area, simplify construction and maybe a better sailing vessel by just making it a V bottomed single chine construction with a narrow "box" at the keel line to allow the engine and batteries in the box with the ballast...but what do I know......:D

Now wouldn't that defeat the bolgeresque thinghy all to hell and gone? Besides...there goes all that lovely buoyancy that I have to contend with........

Steve

[Thorne]

I'm also no NA by any stretch of the imagination, but if you took the box keel all the way to the stem, the shape might be really nice for an electric launch -- batteries in the box keel like the one from OZ that WB showed in their Fall 05 issue.

[P.L.Lenihan]

what would be your thoughts????

Steve



Since you asked, I would plant a nice cozy eating nook all the way up forward with comfy benches facing each other and a table running along the centerline, secured at each end with stanchions rising from the floor up to under the cabin or deck structure.The table could be raised horizontally to creat a lounge space.
Just aft of this,say on the starboard side,I would have a big double bunk situated between two bulkheads and only partiallly closed off for "privacy". On the port side would be a longish counter and throughway, which would house drawers, directly across from the berth and,further aft, the basic elements of a galley right on back to the aft cabin bulkhead if need be. Hard to starboard,upon descending the companionway would be the head with possible shower too on the port side if the counter does not run all the way aft to the cabin bulkhead.
The berth would then be located closest to the pivot point and be less active,ie;less violent motion in heavy conditions, then a forward V berth. Also, having lots of room for both shoulders and feets it may represent a familiar sight to say,perhaps, a significant other or the like, new to boating but not wishing to offend:-)

That's my thoughts Steve...but I must say that your thoughts will be far better suited pour toi and besides,I always enjoy seeing other folks original arrangements.

So,your turn :-)


Peter

[JimD]

Paul Fisher uses scrap filled ballast box keels on many designs, both flat bottom and multichine. Have you had a look at them? Might give you some ideas: http://www.selway-fisher.com/Yachts.htm

[htom]

I think you're going to get a lot of slap noise from the overhangs, and think that the thing to do is to pull the ends of the keel out to the stems. Chinese schooner rig, to empty the cockpit and allow more lightair sail area.

[Lewisboats]

changed because I stuck my big foot in my bigger mouth

[Dave R]

Steve, I'm looking forward to seeing this boat of yours in a few weeks at the messabout on Lake Pepin. I suppose you won't be needing a campsite, huh? :D

[Lewisboats]

Due to overwhelming demand on this and other forums...an update with the Keel extended to the bows and angled aft. Displacement increased by 675 lbs.

http://angelfire.com/ego/lewisboatworks/Stuff/30BoxKeelBoxBoat.JPG


I LIKE IT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 1

[Lewisboats]

Steve, I'm looking forward to seeing this boat of yours in a few weeks at the messabout on Lake Pepin. I suppose you won't be needing a campsite, huh? :D


Yeah... right...Just come up with it today and ready for the water in 3+weeks...NOT!

I haven't even finished Guppy yet. In fact I might only be bringing my son's ScoutCanu...It is the only one that is in decent shape...and that is debatable.

Steve

I already talked my way into a tent spot...HA!

[Lewisboats]

Since you asked, I would plant a nice cozy eating nook all the way up forward with comfy benches facing each other and a table running along the centerline, secured at each end with stanchions rising from the floor up to under the cabin or deck structure.The table could be raised horizontally to creat a lounge space.
Just aft of this,say on the starboard side,I would have a big double bunk situated between two bulkheads and only partiallly closed off for "privacy". On the port side would be a longish counter and throughway, which would house drawers, directly across from the berth and,further aft, the basic elements of a galley right on back to the aft cabin bulkhead if need be. Hard to starboard,upon descending the companionway would be the head with possible shower too on the port side if the counter does not run all the way aft to the cabin bulkhead.
The berth would then be located closest to the pivot point and be less active,ie;less violent motion in heavy conditions, then a forward V berth. Also, having lots of room for both shoulders and feets it may represent a familiar sight to say,perhaps, a significant other or the like, new to boating but not wishing to offend:-)

That's my thoughts Steve...but I must say that your thoughts will be far better suited pour toi and besides,I always enjoy seeing other folks original arrangements.

So,your turn :-)


Peter

Na...I like what you have described... any chancy you could do up a sketch of what you have in mind and put it up here? You would have an 8 by say 20 ft space to work with...with 6.5 ft headroom along the centerline and 5 ft or so headroom along the chines/shear in the cabin area.

Steve

[Lewisboats]

Been doin' some refining of the hull and Keel shape based upon things pointed out to me. Here is the latest iteration (just the hull)

http://angelfire.com/ego/lewisboatworks/Stuff/DE3090SV_Linesplan.JPG

[Lewisboats]

More refining...trying to get the displacement down...the bloody thing is a cork! I took out some of the chine width, it is down to 6.5 ft now. Thinking about some water ballast to reduce possible trailer weight. The waterline shown still displaces 5.82 tons. If I could get unloaded road weight to 3.8 tons I could use a 1 ton pickup (10,000 lbs tow cap) to haul it.

http://angelfire.com/ego/lewisboatworks/Stuff/DE3090SVflare_Linesplan.JPG

[Bruce Taylor]

the bloody thing is a cork!

Well, that's kind of the point, isn't it? :D Somewhere, Bolger describes the box keel as the best way to get buoyancy into the ends without making them too blunt to slip efficiently through the water. (And, from what I've seen and read, they work admirably.)

If you want less buoyancy, why not opt for a simple deadrise?

One more thing: how about getting the forefoot out of the water? On Bolger's box keels (the ones I've seen, anyway) the bow sweeps up and the stem is dry.

[JimD]

One more thing: how about getting the forefoot out of the water? On Bolger's box keels (the ones I've seen, anyway) the bow sweeps up and the stem is dry.

Either well out of the water or well in.

[kenjamin]

I'm enjoying your doodling design. I vote for lots of water ballast. I'm using lots of it in my Caledonia Yawl fishing version. The centrally located water ballast on Xena will also serve as a live well for bait fish and a motor well too. I'll also be carrying enough jugs of air to float her above the sharks and cold water should I get a Titanic-like rip in her bottom. Water ballast is neutral and allows the wood to float with a little help from my eight six-gallon water jugs.

Personally, I'd like to see something like a Swaggie only more flat bottomed with Paradox's chine keels and Stone Horse's raised deck with lots of water ballast (half sink the thing) and a foam core upper half so you will always have a place to sit above the sharks and cold water no matter what shatters the hull. Oh, and also a shock protected dagger board for working to windward. A design trailer weight of 3000 lbs. (for like a crew cab Nissan Frontier) and unsinkable would be just peachy. That V-6 in the Frontier is a work of art.

[Lewisboats]

Well...here is the latest on the Noodle. I dumped the box keel as too much trouble. I couldn't get the displacement down to a decent towing weight. The picture shows a displacement of 10850 lbs in salt water drawing 21" without appendages. Reducing the draft to 19.5 gets me to 9570 lbs. Total height from external keel line to crown is 7 ft so headroom should be about 6.25 ft. There is a lot of windage with the vertical topsides but the slope of the cabin sides and crown should help a bit. I look for about 24"-27" draft with a small center keel and bilge keels with retractable boards for most of the LR. The design is more conventional...Bummer...but getting the box keel to work just doesn't justify the benefits. Getting the Bilge keels and center keel even and flat for and aft would allow for fairly level beaching/bottom resting... provided you have a fairly level bottom to rest on. Trailer weight should be somewhere around 8000 lbs in lightship form (only about 30% of stores and no water ballast). It should make for a decent camper on the trailer too.

Steve

http://angelfire.com/ego/lewisboatworks/Stuff/30ftboxboat.JPG

[JimD]

The box keel was a good idea, it was just twice as wide and twice as long as it should have been. As for the superstructure now the profile looks like an old car. Why do want a boat that looks like a '70s Buick? Critics everywhere, eh? ;)

[Steve Paskey]

Why do want a boat that looks like a '70s Buick?

That could be a real problem in the Florida straits ... the Coast Guard might stop you, thinking you'd set out from Cuba ... :D

[Thorne]

You are SO close....

;0 )

http://www.luckhardt.com/buickboat.jpg

[donald branscom]

I feel like that last drawing without the box keel is best. Too much wetted surface friction.

The cabin top forward slope is not practical. try walking on one.
AND when you are building the interior that rounded slope is hard to deal with.

i like the idea of water ballast because it can be used as drinking water too, and then filled with seawater as you go. Compartments.

[JimD]

Got a stability curve calculated yet? At what point would she roll right over and at what point would she roll right back up?

PS - No offence meant by the Buick quip. I like boxy looking cabins but to each his own and its your boat. Seven feet headroom? Impressive!

[Lewisboats]

Nothing wrong with Buicks...comfortable...powerful...elegant...and a Grand National goes for 100 Gs now. Flooring and tankage would reduce headroom to 6 ft along centerline. Bilge keels and boards were already mentioned in my last post...really the only way to get decent grounding with deadrise. I added a bit more deadrise, modified the rocker a smidge and managed to get down to 4 tons of displacement @ 19.5 in draft for the hull alone. Appendages would get it to about 3 to 3.5 ft. Now...if I can manage 1000lbs of water ballast and get supplies when launching I've got trailer weight down to 3.35 tons or about 7500 lbs. This is reasonable for a 30 ft shallow draft boat. BTW...there are no plans to rush out and build this thing...this is mostly an excercise but still may be a possibe build... behind a few others. I gotta get single first...:D :rolleyes: (two more years Wooo Hooo!!!). The cabin is flexible...I threw it on to give some perspective...I am more concerned with the hull shape. No stability curve yet but if it were to lay on its side...there isn't a whole lot to persuade it to go vertical in the right direction...except for the water ballast...then again...with a narrow cabin entry there isn't much place for water entry so the ballast should be enough to roll it back from at least 110 degrees. If I made the box keel too narrow it would only be useful for headroom for about 6 ft of its length and would be rough on the ankles. Otherwise it simply adds too much displacement without any other benefits...in this particular application. If the boat wasn't to be trailerable then it would be a good addition. I am considering a cutter style rig...with the mast fairly far aft and a couple of headsails. This would free up the bows for a decent Vee berth with no mast in the way.

Steve

http://angelfire.com/ego/lewisboatworks/Stuff/30ftboxboaNoKeeMoreRockerl.JPG

[JimD]

Re: Box keel. I had in mind filling it with ballast.

[Bruce Taylor]

And then there's this kind of thing:

http://www.imagestation.com/picture/sraid225/p0f04ebc90eccbc65ab0c8c2e9dd65b1d/e983822f.jpg

[Lewisboats]

Bruce...do you know someone who uses the handle L.P. on the Boatdesign forum? You are thinking alike...internalizing the box and using the enclosed space on either side as the tankage for the water ballast.

[Pericles]

Yesterday, I was directed here http://www.swallowboats.co.uk/component/option,com_frontpage/Itemid,1/

and viewed the videos of stability tests for the Recreational Craft Directive RCD. This could be the starting point for a much large craft.

Pericles

[Bruce Taylor]

Bruce...do you know someone who uses the handle L.P. on the Boatdesign forum? You are thinking alike...internalizing the box and using the enclosed space on either side as the tankage for the water ballast.

I hadn't thought about where to put water ballast, but that seems like a good idea. You'd keep all that headroom.

As for that basic hull type, it's one that Bolger uses fairly often (on Red Zinger, for example...though that one has a transom).

I drop by Boatdesign.net nearly every day, but the only section I check is the software sub-forum. I'll look for your other thread.

[JimD]

Steve, pardon my stoopid question but what software are you using? Looks like fun and I'd like to try my luck designing something similar but smaller.

[Bruce Taylor]

FREE!ship/DELFTship.

Steve moderates the FREE!ship group on Yahoo:

http://groups.yahoo.com/group/Freeship_HTandT_Group/

[JimD]

Are there instructions anywhere on how to use it? Ya know. Somthin that sez here's how you plot points and heres how you make calculations of what you've just plotted, and so on...?

[Bruce Taylor]

For DELFTship Free and DELFTship Pro, there's a downloadable manual and a couple of tutorials on the DELFTship site (under Support/Download/Documents)

http://www.delftship.net/

For FREE!ship 2.6, there's a manual on the sourceforge website:

http://sourceforge.net/project/showfiles.php?group_id=140466

Some time ago I put together a few simple tutorials and Steve has posted them in the Files section on his Yahoo site. There are a couple of other tutorials in circulation.

If you have specific questions, I can probably put together some step-by-step instructions (Chad and I did something along those lines a few months back, when he was designing a canoe).

[JimD]

Thanks, Bruce. I have downloaded the delfship free program. I didn't see the manual. Perhaps I just need a little help navigating around the software. I appreciate the help but don't want to impose and ask you and others to repeat things that have been covered elsewhere a million times (like posting pictures on the forum, etc) I will peruse the yahoo site and hopefully not get too frustrated.

[Bruce Taylor]

Everyone gets frustrated at first. When you get the hang of it, though, you'll have a blast.

[JimD]

Everyone gets frustrated at first. When you get the hang of it, though, you'll have a blast.

I dunno if I'm smart enough to figure this thing out :eek:

[Lewisboats]

Have you ever worked with Hulls?...if so do up a simple hull in it, import it into freeship and play with it a bit. You can also start with file new and accept all the defaults, then start working with the result. I use Carene to start most of mine...but that is personal preference having found that I think better in numbers (dimensions). Remember...the fewer points on a line, the fairer the line is...Additional points add additional bumps. Creasing lines makes them hard or soft and corners do the same for points. Always remember to "deselect all" (right click for this menu option in any frame) before selecting point (s) or line (s) so that you change only what you want to instead of that and the previous selection (s). You can only extrude open edges... not every line. To delete certain parts of panels turn on the faces and select the faces rather than edges or points. Try collapsing extra points get things together. If you have leak points, look for turquoise points under the waterline and set the Y value to 0. you will have leakpoints above the waterline along the edges of the boat unless the entire thing is enclosed. Don't worry about those unless they affect the hydrostatics. Oh...and read the manual to familiarize yourself with the buttons and commands. To scale something done in metric to feet is done by deselecting all, then going to Transform, Scale and entering .3048 in each of the three dimensions. Make sure to set the properties to feet too but only if the original is in meters. For example...Carene does things in metric and the default for Freeship is metric. After importing the file I go to properties, change things to feet, then do the scaling. I then correct the Max Beam location and Draft back in Properties and then my Hydrostatics are bang on.

[Bruce Taylor]

I dunno if I'm smart enough to figure this thing out :eek:

I had exactly the same thought at first, and I've watched a lot of others struggle with it. Once you "get it," it's really pretty quick and easy, and you won't remember what it was you used to find hard.

For people (like you and me) who are used to reading linesplans & lofting from offsets, the "control net" system used in 3D modelling is pretty confusing.

It took me a while to figure out that the control net isn't my boat, and that the "points" in it are not the same as the points one marks out when lofting (or drafting) a hull in the traditional way. The curves of the boat sort of "float" inside the control net, and the points exert control over those curves.

I kept wanting to "draw" the boat, and found it incredibly cumbersome to have to make new shapes by "extruding" edges and adding new faces. But eventually I figured out that it's really more like "modelling" than drawing. Once you've nailed down some of the basics -- what X, Y and Z are, how to close up the transom, how to eliminate leak points, etc. -- the logic of the method should start to become clear.

Sooo, then....questions?

[JimD]

I would like to start by using Matt Layden's Paradox for inspiration. (This is much more the boat I was thinking of when I started the ill fated Bolger Micro thread). As you can see she is very simple - a flat bottom, near plumb ends, near vertical flat sides - a real Bolgeresque box. Mine, however, will have a scrap filled ballast box bolted to the bottom and likely a couple bilge keels to keep her upright at low tide, adding perhaps 8 or 10 extra inches to the draft. Very shoal is not nearly as important as righting arm. Mine would also have a true self bailing cockpit, albeit a small one. She would also have auxilliary power from a 65# thrust minnkota troller run by two batteries that would sit in the bilge or perhaps even in the box keel. The motor and batteries I already have. If you can give me any more hints on how to manipulate Delftship toward this end please don't let me stop you. In the mean time I will try to get through the freeship manual. Sorry about the beeeeg pictures.

http://home.triad.rr.com/lcruise/Graphics/parad4-0002r.jpghttp://www.microcruising.com/Graphics/pdx25.jpghttp://home.triad.rr.com/lcruise/Graphics/parad4-0005.jpg

http://home.triad.rr.com/lcruise/Graphics/plans1r.jpg

http://home.triad.rr.com/lcruise/Graphics/plans2r.jpg

http://home.triad.rr.com/lcruise/Graphics/plans3r.jpg

[JimD]

Steve - in my enthusiasm I realize I just sorta stole your thread. Shall I start a new one or just carry on? :o

[Bruce Taylor]

One way to proceed would be to load the plans as "background images" and use them as guidelines for your own design.

First, start a new design. File --> New, and enter the main dimensions: LOA (4.2m) , beam (1.23m) and draft (.23m).

Then, right Click on mouse --> Background image --> load

To position the background image, Right CLick --> background image --> origin, and then use the mouse to drag the image into position.

Then, scale the image. Right click --> background image --> scale. Once "scale" is engaged, click on the bow of the background image and enter 4.2 in the "x" coordinate position on the popup dialog (the first of the two numbered coordinates in the dialog box). That tells DELFTship that the length of the image should be scaled 4.2 meters (the other dimensions will be scaled automatically).

http://www.imagestation.com/picture/sraid225/p05a9dcd4018973a8489594976b69ed50/e9740c29.jpg

Do the same for plan view, and bodyplan view, and then line up your control points until they exactly reproduce what you see in the background image.

http://www.imagestation.com/picture/sraid225/p5c9d42a95da4da1f5150969077514166/e97403a9.jpg

Once that's done, you can clear the background image and begin altering the design to suit yourself.

I made up a quick and dirty example, using the lines you posted.

http://www.imagestation.com/picture/sraid225/p9763fd36c85012499aa36164379c7fa6/e973ce80.jpg

PM your email address and I'll send you the .fbm file

[JimD]

Bruce, you old sea dog! PM with email address sent. :)

[Bruce Taylor]

You got mail.

[Lewisboats]

You got mail.


could you send me the .fbm too...I would like to compare it to my own attempt. I stretched it to 18 ft though with a 6 ft waterline beam.

Steve

[Bruce Taylor]

Steve, PM me your email address (it doesn't seem to be listed on your website & I've mislaid a lot of my old emails).

[JimD]

So I've made a few changes, I think. I'm going to print the manual in hard copy tonight and give it a good read. In the mean time I've just been having fun pulling a few lines around. Here is the profile Bruce sent me to get me going along with my changes:

http://www.imagestation.com/picture/sraid225/pcc75d79663b93d154e40d120e11f4226/e970affd.jpg (javascript:viewExifData())

http://www.imagestation.com/picture/sraid225/pe74b291bb1ae609ba48451c09d3a7852/e970aff3.jpg (javascript:viewExifData())

The cabin has moved forward to allow for a cockpit, freeboard at the bow is slightly increased and has also been pulled down a few more inches below the waterline. Next is to figure out how to add a keel and figure out how to interpret the hydrostatics.

[JimD]

Also, I may add a little flare forward to allow for a sharper bottom, and raise the side decks so the cabin is full width. The final version could end up looking a lot like a stubby, pint sized verion of the Atkins' 24 foot New Hope, less the raked transom:

http://www.boat-links.com/Atkinco/Sail/images/NewHope-3.gif

A keel something like this, but no centerboard:
http://www.selway-fisher.com/Simp20d1.gif

[Bruce Taylor]

Here's a rough-and-ready tutorial on keel-making in FREE!ship/DELFTship.

http://www.imagestation.com/album/pictures.html?id=2115454673

Since I put it together, Martijn has added a rather sophisticated "keel/rudder wizard" to his program, which enables the user to generate a variety of foils and estimate lift and drag. For generating a simple box keel, though, or a combined keel/centerboard assembly like the one in your last pic, you'd be better off to build the appendage yourself, as shown in the tutorial.