Towable layout bottom

Nick Zito

Active member
Curious if anyone has a towable layout they'd be willing to send a photo of the bottom. Tried search and Tony H mentioned a photo but I can't find it.

We have a big two man that we tow our but it's pretty slow. Was wondering if the bottom could be changed slightly to tow a little faster (not 30mph)
 
Nick, there is nothing you can do to a current hull that won't significantly affect how it will lay on anchor. Because of the deck shape, falling to the waterline, it will submarine. Unless you can get the bow raised so it can not submarine, and that takes some real shaping of the bottom of the hull which all adds displacement. Though while I am typing this I wonder if a hydrofoil could be added? Anyway, on a Kalash that I reburbished a few years back I added a skeg so that when we lifted the bow out of the water to tow, the stern would track. Without it it was real squirrely and wanted to twist and roll under the wake from side to side.
 
Nick~


Like Dave, I immediately thought of a skeg. Here's the one I put on White~Wing:


17 - No, not copper bottom paint on a winter boat.  Just red primer - because I had it on hand - and



I tracks and tows beautifully - about 40 feet behind the tow vessel:



13 - Towing true..jpg



But - more important - I am wondering what problem(s) you are experiencing. Does she dive?


Where is the attachment point for the tow line? Can you mount one beneath and behind the bow/stem? Do you tow with a single line or a yoke?



As with Dave's thoughts about a foil, I can imagine a "step" added up forward on the bottom.


Got photos?


All the best,


SJS


 
Steve/Dave.

Apologies for the picture quality. The layout has got to be 400lbs and my right arm is in a sling after getting my bicep attached, so the tractor isn't working today. I wasn't sure how well the thing could be towed with the box that extends into the water, certainly doesn't have a skeg either. Wasn't sure if the bottom needed to be made more like yours Steve. I could see attaching a ring or cleat below the bow that would raise the thing above the water. Don't mind the hasty dripping epoxy patch, I haven't had time to clean this thing up. It needs a real overhaul.

Typically we don't haul this very far, but there's a new spot I want to try that's a bit of a ride and there's no way in hell this will be lifted off the water onto our boat
FD6013D0-3F10-4C36-A756-DB583A8A95A3.jpegD2A5680A-11AC-41ED-BAFD-E679F9C42676.jpeg63585E90-8045-4EF9-BF3F-35EFFF0813E1.jpegF0372989-12A8-4D35-9852-A3AB416FB5D0.jpegB28883B7-2D36-4790-AEDC-46CCF3D4207C.jpeg
 
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Nick~


I'm still wondering (from photo #3) how you flipped the trailer over onto your vessels.....


I would change the shape of the bottom with a little bit of framing, some urethane foam, and some heavy 'glass (1708 biaxial).


The new "keels" would be treated 2x4 on edge. The perimeter could be 1/2" PVC lumber, tapered from the depth of the box (well) and diminishing to nothing at the bow and stern. I would fill the space with urethane foam (insulation board) and fair it with a rasp, Surform and sandpaper. The framing could be attached to the hull with thickened epoxy. The 'glass would cover everything and fair out onto the bottom by about 2 inches all around.



Zito Layout - Plan View.jpg

A screw eye or towing ring should be fastened into the 2x4 - and set in 3M 5200 - about 12 inches aft of the bow. Similarly, the skeg should be added after all the 'glassing is done, fastened with s/s lags and set in 5200.


Zito Layout - Profile .jpg



Make sense?


SJS
 
Steve,

Mostly. Would the foam also go on the sides of the well? That is to say, would it look like this from below (photo below).
image.jpg
 
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Nick

Jeff Smith designed a towable layout and I saw the plans many years ago. The aesthetics were impressive and the design was ingenious. When he passed away I looked all over his house for the plans but could never find them. He talked about building the boat for many years but never made it past the drawing stage and some concept experimentation. But from what I remember he incorporated a bladder in the bottom of hull that filled with water. The hull had two skegs that were actually passage ways for water to enter the bladder area under the occupant. Once in place and with empty bladders the hunter would open a flapper valve on the top deck that resulted in the bladder filling with water entering through the skegs. Until the valve is opened water can't get into the bladder even though there is a passage through the skegs. The flapper valve gave air a way to escape letting water rush in and thereby lowering the profile and making the boat very stable. When it was time to leave the tender boat would simply start towing the layout. Water in the bladder would then be drawn out through the skegs. Rather quickly I might add due to the massive sucking action involved. I think Jeff calculated the empty time to be well under a minute. The upshot of all of this is the hull could be designed to be a planing one and thus quite towable, yet capable of nestling down in the water when it was time to hunt.

It's a shame I couldn't find the drawings. I do remember Jeff built a prototype skeg and tested its water throughput which was amazingly fast given the pressure differentials involved. Jeff was convinced his design would become the gold standard for towable layout. It wouldn't surprise me...

Eric
 
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Search my name and Kalash and see how we towed at speed (BBSB speed) the Kalash with a cheap aluminum V hull full of decoys.

Something I considered, but never tried.... is: I set a pr of pad eyes under the deck about 3ft back and intended to add a bridle that had either a jumbo pot buoy or similar under the bow of the layout, so that the bow was floated by it. What I could not figure out was how to remove it to hunt without getting real fancy, or wet.

Tony Homer applied for a patent on a apparatus that is supposed to work with all layouts, that I think snubs it close to the tender and keeps the bow high.

Anything added to the hull that offers any buoyancy, will make the layout not sit well I am afraid.
 
I'd be curious how much buoyancy it would take to get tank to float. Though I guess a bunch of foam would probably be enough. Maybe a few milk crates of lead in there...
 
Steve,

Realized I never answered your question. She does try to dive when we pull her. I've also not pulled her at any speed because of this. Even if the diving was corrected, I imagine a skeg would need to be added. The spot I want to go is 6 miles from the launch. 2 of that is slow on the river getting out, but another 4 going 10knots would be less than ideal. I know I could also snag a few lighter ones but that defeats the fun, and it's much more costly.
 
Nick~


As Dave mentioned, any volume added below the waterline will add buoyancy. Therefore, I would limit the filled area to the width of the well - mostly so that water will flow beneath and beside it.



So, you might try adding just the bow area first - and then see how she handles. You could certainly add a skeg behind the well without adding the filled stern area. I do not know what sort of turbulence would be created right aft of the well if you approached planing speed.



Eric's description of the fillable chambers makes me smile. When these new-fangled layout boats came on the scene with the wells that put the gunners' bodies below the waterline, I wondered how they complied with the long-standing prohibition on batteries and sinkboxes - which prohibit "concealment of the hunter's bodies below the level of the waters surface" (or legalese to that effect). Batteries used ballast weights - most often in the form of cast iron "wing ducks" to get the cockpit almost awash. Sinkboxes used floodable/pumpable chambers to get the same effect.


On Great South Bay, gunners turned to "scooters" to shoot open bay after batteries were outlawed. Although some (especially those of whaleback design) float with their chines close to the water, many wanted the nose to rise up when towed - and so shaped the forward hull sections accordingly.


IMG_7945.JPG



Note the skeg. This "flattie" was often hauled up on the stern of the mother ship - but was also towed. (And removable ballast is used to get the stern down so it won't slap on the water.)



6 Bottom from stern 1.JPG



I know that thousands of Broadbill were shot from this vessel. Note that we almost never have dead calms on Great South Bay - and so shadows from plumb sides, et cetera are of little concern.



1 sm Strung - Sports Afield November 68.jpg



Any way you like at it - you've got yourself a fun project!


All the best,


SJS



 
David Clark did it. It tows at 40 or 10 miles per hour. I can not find a picture of the bottom but I now David has pictures of it.
Phil
DSCN2142.JPG


WhiteCap 14 002.jpg
 
Phil~


Gorgeous vessel! My knowledge of "contemporary" duckboats is limited. Did Dave make the whole thing - or modify an existing design?


I wonder if he can bring some photos - of the all-important bottom - to Hauppauge next week.....



All the best,


SJS





 
Agreed. Steve if I have any further questions I'll hunt you down at the show so we can discuss in person. I'll be fresh out of the sling after 3 weeks, which will be a welcome relief.
 
Steve, considering the bow portion of the well slopes towards the bow itself, like a ramp, should I be continuing the "bow" to about 2" from the edge of the where the front of the boat meets the water, or just adding a tow ring and a skeg to its current condition. The drawing you made shows both bow and stern of the well being truncated, the bow is not, but the stern is.
 
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Steve, The bottom is what makes Dave's boat work the way it does. The top of his boat is 2 Estuary boats laid up cut in Half and glassed back together up side down. The cockpit is cut out of the now top. I know I have seen the bottom pictures some where but can not seam to find them. He is going to the Long Island show next Saturday.
Phil





Steve Sanford said:
Phil~


Gorgeous vessel! My knowledge of "contemporary" duckboats is limited. Did Dave make the whole thing - or modify an existing design?


I wonder if he can bring some photos - of the all-important bottom - to Hauppauge next week.....



All the best,


SJS




 
Good morning, Nick~


I see that now - from one of the inverted photos. So, yes, it would seem that you can mount towing hardware below up forward. Can you reach in - from within the boat - to back up the hardware? (If not, you could install a deck plate (Beckson) through the foredeck so you can be sure the towing eye is backed up, secured and waterproof.)


I look forward to seeing you at the Show. I'll be sure to bring a sketch pad and pencil!


BTW: Just to be clear, the gunning vessel I showed in one of my earlier replies was not a Scooter. Rather, it was a skiff or flattie - much simpler and cheaper to build than a true Great South Bay Scooter - and most likely built after WW II. Here is a Dodge & Krowl Great South Bay Scooter - from the 1920s or 30s:


Canvas cover full.JPG



It trims closer to the water with a gunner providing some ballast.....


sm P - ACH 07.JPG





See you soon!


SJS





 
I'll have to crawl in there after the sling comes off. Not sure how far I can reach, it's been some time.
 
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