Duckworks Magazine - Building the PUD-g

Building the PUD-g

Design by Warren Messer - Seattle, Washington - USA

Part 1

In the rush to build as many prototype hulls as possible this year; the completed FlyCaster was quickly removed from it's place of honor on my building platform so the two sheets of plywood for the PUD-g could replace it. Building new hulls has become an obsession with me this year, and building the PUD-g seems to have reached a peak. I hope. It may slow down a bit, as most of the hulls queued up are too long to fit in my current work space. I will either need to add on to the barn, or sell out and move down to the Texas coast where I can build and use my 18ft cat ketch, Raid design. Or go single hulling with my 15ft asymmetrical hulled catamaran. Where was I?

The layout of the hull panel outlines on the stacked plywood sheets when very smoothly, with only a couple of changes from the dimensions I had calculated off the computer drawings. Mainly it was adjusting two of the bow corner points so the "arc lengths" of the two mating edges were within 1/8" of each other. I had to use my layout batten, and measure the distances pencil marked on some masking tape. All my measuring tapes would cut the corners between the brad nails and give me a false distance. I have to get a cloth measuring tape and glue it to the batten for use on other hulls. Once all the adjustments were made, it was time to cut out the panels.

It had been a while since I had worked with 4x8 sheets of plywood, and they looked so small compared to the 5x10's I had been using on the last three hulls. Moving the clamped pairs around on the work platform was a lot easier. I was also chuckling to myself about how small the panel pairs were after I had cut them out and set aside; and kept asking myself if this was really something to spend so much time on. Since this PUD-g is not the same hull as the PDF model you can download in my area of the "Plan" section.

That PUD-g, wasn't. Once I think I am done with the basic hull design, I print, glue, cut out, and assemble the latest model; then hang it by a thread over my kitchen counter where I eat all my meals. I then spend days/weeks looking at it as the model spins in any chance breezes that pass by. Or I just blow at it. Sooner or later, some thing about the hull just doesn't look right, and I give it a good "eye balling". Turning it around in my hands and wondering what's wrong with the hull, that it makes me second guess what I have already done. This time the hull just didn't look big enough. I didn't really want to make any changes, because it was too pretty now. But I know now that a small boat, (less than 10ft) can not be really sleek and have the volume to carry any kind of load. A small pretty boat is actually just a scaled down version of what it should be to do the job.

To prove to myself that I needed to make some major changes, I laid out the hull outline on my kitchen floor with bits of masking tape and then sat in the middle of it. Yep, too small. Time to add some steroids to PUD-g's diet. Now I get to spend even more hours at the computer, then the making of seven more models until I was happy with the design. Which meant throwing away several pages of completed detail drawings. :(

But as a confirmed scab scratcher, I had to do it. Nobody is going to be more critical of my designs than me. No one! This pudgier PUD-g is not as pretty as the first, but can more than stand up to the demands placed on it, and still be true to the "mission statement" that I set out with when I first though of designing this hull. (see the cover letter on the PUD-g in my plans area)

With the hull panels all cut out, it was time for the "outside" photo. I was still wondering what the heck I was doing when I saw the photo, but that changed to fatherly love when I had the panels all wired together. Like babies, kittens, and puppies, something about miniatures brings out a protective instinct, and an obsession to nurture. It became necessary to force myself not to work on the boat and live "my" life. Even as I write this I am way behind on the plan drawings and updating the text instructions; and the hull is 90% complete.

Hull assembly when smoothly, with no problems. I did find a couple of flat spots along the hull seams, but some 1/8" shims fixed those. I wasn't sure if it was from the design or cutting out the panels. Judging from their locations, it had to be me moving slightly inside the line as I cut. No big deal. GelMagic and EZ-Fillet can cure all my mistakes.

With the PUD-g, I wanted to make a pure "deck" boat in the ongoing wars over hard-shell or inflatable tenders. As a ships tender, I wanted a strong workable solution, that was 100% practical. No extra fancies on the interior, and lots of secondary flotation in case of a breaking wave on a beach landing. I also needed room for people and their supplies. As a seakayaker, I knew the benefits of watertight storage compartments, and the extra flotation they have built in. As a whitewater canoeist, I know of the added safety that buoyancy/displacement air bags give in keeping you and the canoe on the surface in big water. With that insight, I made the interior seating on the PUD-g part of the hull, with storage, and reserve flotation.

On the Laura Bay, I had boxed in the area around the daggerboard case to use as extra flotation. I now wished I had added a 4" quarter turn hatch to each side in the plans. I will do this to my own hull later. On the PUD-g, I have added the four inch hatches, plus two six inch hatches on either side, of the forward seat compartment. If you so chose, you can add an extra bulkhead to divide it again. Just offset one hatch forward of the other. That forward hatch may be reduced to a four inch model to fit better. The stern seat box is wider than the main center seat, and is fitted with a larger eight inch hatch. All the seat panel to hull seams are filleted with EZ-Fillet, and a layer of 2" glass tape on the outside. World cruisers can add a fillet to the inside seams if you chose to do so for added strength.

Because of the heavy curvature near the bow with this design; I have gone to the "spaced rail" gunnel system. All the rail parts are ½" x ¾", ripped out of Philippine Mahogany. Once I have ripped out the rail stock, they are stacked into two pairs. Port and starboard, with the "inner" rail on top, to form to it's mate. The bow ends are tied together and raised at least 18" off the floor. The stern ends are raised about 8" off the floor. I added some loosely tied cord at three places along their length to keep them together, but able to slip independently. I then placed some sandbags on the rails, and closer to the bow end to induce curvature. More bags are added and moved closer to the bow end over several days as the wood takes a set. You could also do this by making up a jig out of an eight foot 2x4 with the two risers nailed at each end. Then the rails could be tied to the jig, and forced into a curve over several places. You do not want any "point" loads. A light spraying of water at the start can help too. The rails need to be kept this way for a week or more to take on a set and keep from "snapping" when you go to install them.

Another problem I encountered was fitting the spacer blocks to the heavy curvature. I didn't want to put excessive pressure on the hull panel and the outer rail by just applying massive clamping pressure to make the spacer block conform to the hull. To get around this, I placed "relief" cuts on the outer side of the spacer blocks; and this let them easily flex to fit the curve of the hull. I only had to do this at the #2-3-4-5 station lines. The other blocks glued up with no problems. I did change the block spacing in the plans drawings, from what I used on the prototype hull, after rethinking the spacing pattern. The new scheme is a better fit.

With every new hull prototype, I spend a lot of time thinking about seat height, and how to make sure that measurement will remain the same from bow to stern. Half the battle is making sure the hull is sitting (to what I think it will be) on it's lines. Serious head scratching, but I am usually on my (it's) mark. With that information, I then set up a (rubegoldberg) series of strings and scrap sticks to project that idea to the hull. Then I go about measuring all the heights and widths for the various parts that make up the seat and daggerboard assemblies. After a few cardboard cutout mockups, I can then mark and cut out the plywood pieces. Sometimes they become backing plates for future projects, and I go scrounging around the shop looking for more bits leftover from previous hulls.

The stern seat assembly went together smoothly, with a couple of adjustments to the bottom edges of the panels to fit the hull. The whole assembly was jump stitched, filleted, and glass taped on the inside before I attached it to the hull. With 6mm plywood backing plates for the top seat panel, and for the 8" hatch area. I also added a layer of 6mm ply, and a piece of ¾" x 1" rail material, to the inside of the stern panel to give extra support to the area where the rudder gudgeons are mounted. The rail material and the set assembly had to be relieved to fit this addition.

In order to judge how the "main" seat assembly would go together, I had finish the daggerboard case. The PUD-g is using a NACA 0010-8" cord daggerboard. So I needed to figure out and design the shape, find the overall width of the foil, and then determine the case's open length and width to have room for the daggerboard to "gybe" inside it. Once that was done, I could cut and assemble the case.

One of the things I remembered to do this time, was to measure and mark a line 2" offset from the keel line seam. On my other hulls, the filleting and glass tape layers hid it's true location and I had to crawl under the hulls, and drill a pilot hole up from the bottom. With this line, I was able to reestablish the true keel seam and mark on masking tape that location. From my half model CE/CLR locations, I knew where the aft side of the DB case would go. Out comes the centerline cord and the "pencil bobs". After making sure the hull was still level on the work platform, I centered and aligned the DB case, and held it in place with a weight. More sticks to determine where the main seat would meet the bow, and a couple bits of masking tape for that location.

Now the fun part of figuring out how the main seat side panels would be shaped and fit to the hull. More cardboard, mark, cut, mark, cut, mark; you get the idea. Once I had a shape that seemed to fit, I tried it out on the other side. Close enough for EZ-Fillet. With them taped in place, the top seat panel was cut out of cardboard and everything was taped together to see if it worked. I then took some measurements off the cardboard mockups and projected those figures onto the plywood as a check for me and my numbers. Then a test of faith when I cut out the plywood panels to those measurements. There was some reshaping to the bottom edges before finally epoxying them in place. All hulls will have to have some reshaping due to the variability's of construction.

With all the parts cut and shaped, it was time to start making things permanent. The daggerboard opening in the hull was located and marked with some pilot holes. I do the cutout when the hull is upside-down getting it's bottom glassed. The DB case is located, jump stitched, then EZ-Filleted and glass taped in place. The main seat top and side panels have their backing plates attached with epoxy or GelMagic; and the hatch openings located and made. Everything is then coated on all the inside panel faces and edges with two coats of epoxy. The main seat side panels are then attached to the DB case with some stainless pilot screws to maintain alignment, and a thick layer of GelMagic on all the mating surfaces. The top front width of the side panels is checked and held in place with a bit of scrap and clamps or screws. The side panel to hull seams are jump stitched and everything is left to cure.

The mast step/partner assembly on the PUD-g is a bit different than on my other boats. I haven't finished with it yet, so this is a good place to stop for the time being. To see a lot more photos of the construction process to date for the PUD-g; go to the following link. I will be adding photos until/after the plans are ready for sale. www.flickr.com/photos/pud_g