Concept image

The Project:

I have been thinking ahead to this spring’s boat projects. We did most of our boating last summer in the kayaks, only taking out the big boat a couple of times. It was a particularly windy summer and we often launched the kayaks either on one of several local rivers or on the calmer side of nearby Indian Lake.

One idea that I’ve been thinking of for a while is to take advantage of some of those windy days by (1) add a sail, rudder and leeboard to the dory, and (2) add a small cabin to the boat for overnight, on-board camping. The image above is my initial concept drawing of how the cabin might look on the boat.


Getting Ready:

One of the most common jokes among or about home-builders of boats concerns the guy who builds a boat in his basement or wherever, and can’t get it out without dismantling his house. So far we have managed to avoid that one. Our dory is a little over 18 feet long, about 54” wide and weighs around 150 lbs. When it was time to get it out of the shop we just tipped it up on edge on an old blanket and dragged it out the door. A bit of a balancing act and nerve wracking, but it worked. Thinking ahead to future boat building projects including this spring’s modifications to the dory, I decided to create a nice, wide door on the east end of our shop.

xI re-framed the east wall, adding a new header and using some large gate hinges, turned that wall into a big bi-fold door. The opening width is about 60”. It takes less than a minute to release the sliding bolt that keeps the wall in place and gently push the door open.

One other small project was to build a boatBoat on dolly dolly for use in the shop. Even with the expansion I made to the shop it is still pretty small (clear space is about 22' x 7') for working on a boat this size (18'- 3" x 54"). The kayaks at 14 -15 feet long and quite narrow worked fine but there is an immovable post in the middle of the shop that gets in the way at times.
The other consideration is that we use the shop for other, non-boat projects, sometimes while the boat is in there. I also wanted to be able to fairly easily adjust the height of the boat. I bought an inexpensive block & tackle and installed a couple of ceiling joist spanning beams (inset) on the ceiling and that made the job of lifting the boat a lot easier. I might invest in another block & tackle so I can lift both ends at the same time. The dolly rolls on 4" double-locking castors and literally glides around the shop but can easily be locked in place. For more serious work I'll clamp on a couple of 1x2's fastened to the wall.


The Plan: - March 25, 2018Sailing Dory
The plan is to make the sailing modifications first and then build the cabin. The cabin's location in the aft end of the boat will especially effect how the rudder is controlled. Looking at the conversion for sailing, item by item, here are some of the details. By the way, this is all my way of 'thinking out loud', so to speak. My way of putting my thoughts in order so I can be fairly efficient when actually working out in the shop. I'll be updating this page as the design process unfolds.

RUDDER/SKEG:
Rudder hardware was ordered from Duckworks early so I will have the gudgeons and pintles in hand when doing the final design work for the rudder. Here is my preliminary design for a kick-up rudder based upon work done by Paul Riccelli at Riccelli Yacht Design.

I have chosen to build a laminated plywood skeg for the kick-up rudder to fasten to. Primary support will be two pairs of 1-3/4" x 1/4" rigid fiberglass straps that fasten the skeg to the stem.

Skeg Fastening Stem Fastener detail
The forward edge of the skeg is routed to fit snugly around the stern rub strip. The support bars will pass through slits in the skin (cut & shaped with a hot knife) and will be bolted together as shown. I plan on gluing 1/4" plywood 'cheeks' to the stem above and below the support bars to help keep them in place. The reason for this system is that this is a very tight area with no opportunity to screw or bolt the supports directly to the stem without making many holes in the skin.

The rudder will be made up from two pieces; the upper, rudderhead, will be attached to the skeg with stainless steel gudgeons & pintles, and the lower part attached to the upper by a 3/8" pivot bolt. The cheeks of the upper piece are to be lined with HDPE to reduce friction.

Rudder/Sked design #2  Rudder design
    Design #2 - April 4, 2018                                                                       Design #1

I liked the looks and smaller size of design #1 but remembered that it might be nice to have a functional skeg even when not sailing. Design #2 does that and also would be stronger since I can put a couple of SS screws up into the keel at the forward end of the skeg. With the rudder removed while rowing the skeg will give some directional control, hopefully helping when rowing on windy days. It is also possible that I may want the rudder installed on those days if the skeg doesn't function as I hope. In that case it might be nice to add foot controls for the rudder.

Rudder control system

Speaking of controlling the rudder, the plan is to install a small, maybe 5" radius quadrant atop the rudder head and have stainless steel cables lead forward along the outside edges of the cabin leading to the mid-ship tiller. The tiller will be mounted below the thwart and hinged and/or removable for times when it's not needed.

LEEBOARD:
I've been in contact with Dave Gentry who designed our skin-on-frame dory regarding this series of modifications and generally he's OK with them but suggested that a daggerboard might be better than a leeboard for this boat, and he may be right. I believe his concern is based upon the lack of framing to support the stresses imposed by a leeboard, which can be pretty strong.

My concern with a daggerboard is having a hole in the bottom of the boat and that daggerboards can't kick up when they strike something like a submerged log or rock ledge. The force of that sort of impact would have to be absorbed by the daggerboard trunk and ultimately by the framing of the boat.

So my solution to this dilemma is to mock up a leeboard support structure and see how it feels when applying lateral forces to it. If it feels OK, that is, if the framing of the boat appears to be able to handle the loads, I'll go ahead and build the real thing. If not, I will switch gears and design a daggerboard trunk with some sort if passive shock absorber.

Leeboard design-1     detail

SAIL:
I ordered a sail kit from Dave Gray at PolySail International. After reading many reviews and recommendations I decided to make the sail from polytarp material; but not the cheap, flimsy, ugly blue tarps from the hardware store. Dave Gray has done his homework and sourced some nice low-cost, high performance poly laminate white tarp material and assembled several sized kits for making your own sail.
Balanced lug sail
I purchased the 'Medium PolySail Essentials Only Kit' that includes a 12' x 16' white tarp, double-faced tape and rope for around the edges of the sail and a brass grommet setting kit with 24 grommets. Sue and I will be sewing all seams with heavy white polyester thread.

The sail design is a 76 sq. ft. balanced lug with two reef points. We added a walking foot attachment to our venerable Husqvarna/Viking Emerald 116 sewing machine since the material is so thin and smooth.

MAST & RIGGING:Mast types
With a basically tippy boat like this it is important to keep the weight aloft as low as possible so I'd like to make a hollow wood mast with the yard and boom being solid wood. There are several ways to make a hollow mast; birdsmouth, coopered or box-section. The mast will be tapered so that complicates it a bit. I'm waffeling -  but like the idea of a coopered mast ( top right) because it uses so much less clear wood and has the potential to be very light. I'll have to do some research to see if there is an easy way to make a tapered coopered mast. On the other hand, a solid mast that is properly shaped can be stronger. What to do?



 
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