Friday, April 07, 2017
QUIDNON: A Guided Tour
In this post I will provide a look at all the more important elements of the design by presenting and narrating detailed views of the 3D model.
We start our tour underwater, as a scuba diver would, approaching a floating QUIDNON from below.
The hull is shown as translucent, to allow you to see the very substantial internal structure. The two keelboards and the two rudder blades hang down at a 10º angle, which is optimal for when the hull is heeled, since a hull this wide (16 feet) isn't going to heel more than about 10º.
The circles on the keelboards (and the rudder blades further aft) are where plates of led ballast will be embedded in the plywood sandwich. The extra weight is enough to oppose the buoyancy of the blades, allowing them to drift down when sailing slowly, but keeping them light enough so that they can bounce off the bottom in the shallows without suffering damage. When sailing fast, downhaul lines keep the keelboards and the rudder blades down against the resistance of the water rushing past. The downhauls are secured using autorelease cam cleats that pop open if a keelboard or a rudder blade encounters something solid. The skipper would then wake up and do an emergency 180º turn, or look at the depth sounder, shrug, and re-tighten and re-secure the downhaul that just popped.
Along the chines between the sides and the bottom are chine runners. They are designed to provide lateral resistance when sailing through shallows, with the keelboards raised, or bouncing along the bottom ineffectually. This feature allows QUIDNON to tack through a shallow spot that only has around 2 feet of water and also allows it to sail off the wind with the keelboards raised, decreasing drag.
The propeller from the outboard engine, in its inboard outboard well, is visible further aft. The engine moves up and down on a track, and can be raised while sailing, to further reduce drag.
Floating gently toward the transom, we notice an interesting recess in the bottom just forward of the engine well. That is where the solid ballast is hung. It is externally mounted, so that it can be dropped before hauling out on a beach, then winched into place once afloat again. It consists of a cement block with steel scrap embedded in it. It's got an eye for attaching a line in its center and 4 pieces of threaded rod—one in each corner. To mount it in place, somebody has to dive down and tie a line to the eye, then stick that eye through a hole in the center of the chain locker, which is right above where the ballast block goes and right below the cockpit. The block is then pulled into position using a comealong. Once in position, the 4 pieces of threaded rod poke through openings in the bottom of the chain locker and secured using nuts.
Finally, we reach the transom, which is going to have a swim step and a boarding ladder, but they aren't shown because we aren't done designing them yet. Note that the bottom is slightly flared as it reaches the transom. This is to provide clearance for the rudder assembly, which is tilted 10º. Also note the recess in the center of the transom, which is to keep the stream of water from the propeller from hitting the transom. For those interested in QUIDNON trivia, the horizontal panel right above that recess is officially called "the taint."
The rudder posts (pipes, actually) are bent forward slightly, so that the pivot point of the rudder blades is forward of their axis. This is done so that it is possible to adjust the angle of the rudder blades so that the steering is as close to completely neutral as you like, to provide fingertip steering, and to keep the autopilot from wasting energy. Most rudders pivot around their leading edge, or close to it, and take a lot of power to deflect. Some people find that sort of steering "sporty." But what works best is when rudder blades are adjusted so that they trail in the water if allowed to move freely but can be deflected with hardly any effort at all.
Climbing aboard using the imaginary swim step and boarding ladder, we see the cockpit populated by two creepy mannequins (they are very useful for figuring out ergonomics, but we are looking for better-looking ones). The seated mannequin is holding onto an imaginary tiller. Yes, QUIDNON uses tiller steering instead of wheel steering, for the following reasons:
1. Whether wheel or tiller, hand-steering is rarely done, because most of the steering is done by autopilot. I generally turn on autopilot seconds after casting off and turn it off again seconds before anchoring or docking. But a wheel clutters up the cockpit the entire time, while the tiller can be folded away when it isn't being used.
2. When you do have to hand-steer it is usually when docking or casting off, and what you want is a tiller anyway, so that you can freely swing it from side to side, instead of having to spin the wheel.
3. Most of the reason to use a wheel is that it allows for a lot of leverage. But who needs leverage when you have neutral steering? The only time you won't have neutral steering on QUIDNON is when you are in the shallows and the rudder blades are kicking up, but then you should slow the heck down immediately. And if you are moving slowly you don't need amplification anyway.
4. If you find that you need to hand-steer for a long time—if the autopilot dies, or if you need to hand-steer because you are ghosting to windward in a fickle breeze and the "sail to wind" function isn't working—then what you want is a tiler, not a wheel. With a wheel, there is just one steering position: standing behind the wheel. With a tiller, you can sit, stand, recline, use your feet, use your hips, tuck the tiller extension under your armpit or rig something up using bungee cords and a line tied to one of the sheets.
Here are the details of QUIDNON's steering linkage. Rudder arms and the tie-rod that connects them are shown in purple. The tie-rod is slightly shorter than the distance between the rudder posts. This is called Ackermann geometry, and allows the boat to efficiently pivot around the keelboards without generating drag, because the rudder blade closer to the center of the circle is deflected farther than the other. Along the centerline is the tiller, connected to one of the rudder arms using a diagonal linkage which allows a certain amount of amplification, to limit the swing range of the tiller to the confines of the cockpit. The tiller is a telescoping tiller that consists of a housing, the tiller itself, and the tiller extension.
Below the steering linkage is the equipment chase. QUIDNON's aft section consists of 2 aft cabins, and between them is a wedge-shaped space taken up by everything that doesn't belong in the cabin. Working from the transom forward, the rearmost section houses the gas tank and two 20-lb. propane cylinders. Forward of that is the engine well. Forward of the engine well, we have the solid ballast block at the bottom, the chain locker above it, and the cockpit well above that.
Here is another view of the cockpit. Note that there are lots of places to sit: down below, with your feet in the cockpit well; up above, on the raised lazarettes, with your feet on the seats, and inside the dodger if the weather is nasty. And you can hand-steer using the tiller extension no matter where you sit.
But you will probably be spending most of the time down below in the cabin, which is accessed using the companionway hatch and the companionway ladder.
This ladder is built right into the structure of the boat and is much more comfortable to use than most companionway ladders found on sailboats of this size. It is also much more than the ladder. At the bottom it has a footwear locker. Next, behind the first step, is a row of plumbing valves. Above it is a row of switches that control various pumps and alarms. Above it is the AC 110V/220Vcontrol panel, for shore power. And above that is the DC 12V control panel. This is a very convenient place to put all this stuff, from every angle.
To port and to starboard aft of the companionway ladder are the two aft cabins. Each has a double berth and a table, and is suitable for a couple. The aft cabins have doors, which aren't shown, because we haven't designed them yet.
Forward of the aft cabin on the port side is the heads, which has a full-size shower stall and can also be used as a sauna. We are trying to design other things into it: a bathtub, a washbasin big enough to bathe infants are both on the list. It will contain a stove that will work either on solid fuel (wood, charcoal) or propane, heat water and provide warm air that will be circulated throughout the cabin by injecting it under the cabin sole.
On the starboard side, across from the heads is the galley, which I won't show you because we are not done designing it yet. It will include all the usual stuff: a sink, a propane range and a fridge, but it will also include a stove, similar to the one in the heads, that will boil water and can be configured to be used for cooking, baking or smoking.
Forward of the galley and the heads is the salon, occupied by some more creepy mannequins. It is large enough to throw dinner parties for up to a dozen people. Above the drop-leaf table there is a large hatch, so that the space is very well lit. There is plenty of storage space behind the backs and under the seats of the settees.
To port and to starboard of the salon are the two pilot berths. They are large enough to sleep one adult, a couple who are intimate and as many as 4 children. They have a sliding door, which allows some amount of privacy. Here is another view of the pilot berth, this time looking forward.
The pipe you see is used to route uphaul and downhaul lines from the keelboard to the deck, and from there to the cockpit.
Below the pilot berths are the ballast tanks, filled with seawater. Freshwater is stored in bladders that float within the ballast tanks. Since seawater, even if strained, contains some number of living organisms who will take up residence inside the tanks, consume nutrients and oxygen and then die, periodically these tanks will need cleaning out. This is done by draining them one tank at a time, then climbing inside and scrubbing them down. Here is a mannequin bravely going where no mannequin has gone before.
And here is the view from the pilot berth looking forward toward the U-berth. Most sailboats of this size has V-berths: awkward, wedge-shaped spaces that offer the best place to sleep in spite of having too little room in the leg area and not enough headroom. Since QUIDNON's bow is not V-shaped but U-shaped, it has a U-berth instead.
We haven't quite worked out what to do with it yet, but the space definitely has potential. For example, it can be set up with sliding doors and used as a master bedroom, at which point QUIDNON becomes capable of housing 3 couples and their children. Here is a view of the salon looking from the U-berth.
Finally, here is a top view of the entire cabin. As you see, QUIDNON can house an awful lot of creepy mannequins! (Prompting one wit to declare that it may be suitable as a slave ship.) But here is the really important point: this is an awful lot of boat in a 36-foot package.