Helium - A 12' Skin-On-Frame Sailboat
Helium on Fidalgo Bay for the Anacortes Small Boat Messabout 5/16/15
Helium was designed and built to meet some specific requirements:
1) Lightweight and easy to car top, quick to load and quick to get in the water. Easy storage: all parts to fit within boat, 100# total weight goal for everything not including the crew. My previous trailered sailboat rarely got used, too much time to get it to the water and ready to sail, it was much quicker to load and launch the kayaks. There was even the thought that it might be possible to comfortably sleep in the bottom for an occasional overnight gunk holing adventure as crazy as that seems.
2) Built for Seattle, deep enough hull to be dry during the colder months with minimum spray getting into boat. The hull will live indoors when not on the water. The rig and sail were driven by local wind conditions
3) RIG: Simple free standing wood mast and spars, no blocks needed. Quick to set and quick to strike. No metal parts to flail about.
4) SAIL: We get more days with mild winds than days with wild ones throughout the year on Lake Union and Lake Washington. A sail big enough to make summer days interesting when there is nary a breeze, but also reef-able when the wind picks up.
5) HULL: Classic look, displacement hull, multi-chine for Skin on Frame construction using steamed frames, lashed and pegged to the gunwales and stringers, no epoxy…Titebond 3 where needed. Plywood and fastener use kept to a minimum....daggerboard/daggerboard case/rudder
Hull was started in mid-June of 2013 and finished in about a month, the rudder/daggerboard/mast/boom/yard took a bit longer. It was September before I float tested the boat and got around to covering it with ballistic nylon and 2 part urethane and making the sail. Boat finally launched on April 13, 2014.
Here are some construction pictures and notes that might be of interest….the boat gets a lot of attention and questions wherever I launch.
This is the first picture of the boat, June 22, 2013. The 3 (fore & aft are identical) frames were based on The Delaware Ducker in Chapelle American Small Sailing Craft, note that I increased the freeboard another 2 or 3". About 1.5" of rocker were forced into each end, gunwales are about 1.5" x .75". The boat is built of clear poplar. LOA is 12' and BOA is 4', stem stands 24" after trimming to gunwales. At the end of the day, one screw per joint, gunwales wired at stem. It took a while to get everything symmetrical and looking good.
The stringers are temporarily attached with a sheetrock screw in pre-drilled holes until everything is set, then they are doweled, glued and lashed. The boat is now flipped and blocked for the ribs to be steamed and bent to shape.
The ribs were soaked for 12 hours in a plastic sheet edged with 2x4s on the porch and a steamer was made from downspout and flashing over a gallon pot on my stove. The hot ribs are bent on the way to the boat and originally were held with clamps made of split ABS tubing, but zip ties proved quicker and easier. Ribs are put in starting in the middle and then alternated bow and stern laying flat against the stringers, so they angle out a bit. The ribs were then left to set for a day or so. The poplar I used bent very easily, the ribs at each end were a bit more challenging and the last rib on each end was put in in two pieces.
Here the boat inner gunwales are installed and the breasthook (a lot of tension on the gunwales at the stem). The gunwales: inner & outer were doweled and glued to the ribs then cut off flush with a Japanese backsaw. The stringers are adjusted as the ribs are lashed for even spacing and aesthetics.These pictures were taken July 3, the hull goes together fast once you get the frames set up and the stock run through the table saw and sanded. Note that a spacer is necessary about amidships or else the hull would distort quite a bit, but over time the wood relaxes into a new shape.
Details of finishing the hull frame: lashing, quarter hooks, mast thwart, mocking up daggerboard case.
The daggerboard case was made of plywood with poplar spacers and edge trim, epoxied inside and glued with Titebond 3. The daggerboard is tapered into a reasonably efficient foil shape and tapers at the top, so it can be pivoted fore and aft to adjust trim.
The rudder consists of 4 threaded eyebolts (with nuts & washers). This tiller was replaced with a push pull one after the first time out.
The mast being laminated from a perfect home center construction grade 2x6x12, the spars from part of a perfect 2x8x10, took a bit of sorting through the piles, but there are frequently pieces that are good enough for a boat mast. The forks for the boom and yard respectively, these are screwed and glued.
The essentially finished leaning in the corner of the living room, the spars in the boat and a float test with the boat covered with Tyvek to check balance.
Skinning the boat using ballistic nylon and 2-part urethane from Corey Freedman (The Skin Boat School), he was kind enough to give me advice on covering while teaching a Baidarka Building Class at the Center for Wooden Boats. Last picture is the mast step (lashed & pegged), center thwart that supports the daggerboard case and the seat rail (pegged & glued).
The cleats & ring are oak, the buttons pine, battens poplar. The Tyvek sail is cut flat, no broad seaming or edge shaping as the batwing gunter with a loose foot will have a great sail shape without that complication. Outdoor carpet tape was used and all the holes were punched and cut out then grommeted, small holes burned with a soldering iron. First time the sail was set up, the rigging was pretty far off. The upper part of the luff is lashed to the yard, the lower half attached with wood buttons. The downhaul picks up the boom and keeps it high. The outhaul ties off then goes to a cleat.
Ready for the water....I did make one mistake, the rear thwart trapped the mast, had to cut the pegs, re-drill and re-glue, no big deal, but it reminded me how easy it is to miss simple stuff.
The hull weighs 65# and the balance of the rig and sailing stuff another 35#. The cart is a modified golf cart that gets the boat between house/car/water. The car roof rack has a couple of diagonals, the boat is rolled up to it, flipped over, slid onto the roof....very easy. There are a pair of stops, one on each ramp to catch the gunwale as the boat is flipped. The mast/boom/yard are tied in the boat, everything else is in a large canvas bag,
The first time out, the sail refuses to take a shape, I had to re-saw the battens thinner, taper the front third of each, raise the yard another foot or so and finally realize that the outhaul was much too tight (the sail should have about a foot of depth at the maximum point. Note the new push-pull tiller that is about 7' long and held to the rail with a piece of bungee, so it doesn't drop overboard.
Most of the issues have been ironed out during the first trips, here you can see the double main sheet that goes through thimbles as holding it in your hand when it is blowing 10 knots is not optimal. These pictures were all from days with winds of 3 to 6 knots. The boat now sails well on all points of sail and in very light winds. You can see Mt Rainier in the background....boat launched from Mt. Baker Rowing Center.
UPDATES SEPT 29, 2014:
Helium has been sailed more than a dozen times in Lake Washington and a number of minor changes have been made and a lot learned about sail trim. We were out a couple of days ago and make 5.2 knots on a reach in a 3' chop after launching from Leschi.
The halyard had a tendency to bind a bit on the way up and jam on the way down, so an aluminum pulley was fabricated and installed at the masthead to solve this issue.....much easier to raise and lower the sail.
The toggles that tie the sail luff to the mast have been removed as they were a hassle to attach. With the downhaul tight, the sail still maintains the same position along the mast and seems to set identically. This has resulted in quicker setting and striking of the sail.
Holes were enlarged where lines pass through on the boom as well as a couple of new ones made to allow easier setting up of the outhaul. I run the lines through the boom and back through the grommet in the sail to keep the boom from dropping as headroom is really nice to have.
A tape mark was put on the tiller and gunwale so that center rudder could be easily found, this was only an issue when setting out as there is no water flow past the rudder and it was hard to tell where it was.
Setting up the sail is very simple, the downhaul is made tight and the outhaul slack enough to allow between 9 and 12" of depth in the sail near the boom. With the tapered battens the maximum draft is about 40% back from the luff.
One issue that is not totally resolved is when Helium is sailed in windy choppy conditions there seems to be some lee helm, I have added 12# of lead in the form of a small ingot to the bow and this seems to resolve the lee helm and created a bit of weather helm. Helium, being very light is highly sensitive to the position of crew in terms of balance, but that is to be expected where a crew of 2 can weight 3 times the empty boat weight.
Generally Helium is very well behaved and fun to sail. When the wind is light, Helium just ghosts along. In windier conditions it easy to sail with the rail almost at water level, yet easily controlled using the rudder and moving one's weight around. The boat is very responsive to rudder input and mainsheet position. I have had the sail reefed to the second set of reef points one day it was blowing 12 or 15, went fast, but had to let the mainsheet go a couple of times when a sudden gust came up.
Still thinking of adding the fishtail propulsion, though that wouldn't obviate the need for the paddles (which are a bit of a nuisance to store on the boat. Eventually going to make a proper Dacron sail in lieu of the Tyvek one. The Tyvek sail works really well and I don't worry about modifying it to fine tune the sail. Interesting note is that the loose footed batwing gunter is cut flat, no broad seaming or luff curve (aside from allowing for the yard), it gets it's shape from the battens and yard to mast angle. I was thinking of adding some lead to the centerboard, but don't think that is necessary at this point. There is still more room for improvement and every time out I try to make a few minor changes to test new ideas and make observations on how she reacts. Now that fall is here, the winds should be picking up and that means lots of good days to get out on the water!!!
UPDATE NOV.21, 2014
I have made a few more minor changes to Helium:
Drilled a hole through the mast step and mast and fabricated a clip to tie them together so that in the event of a capsize, the mast will stay attached and not try to rip out the partners.
Removed the plastic thimble guides on the mainsheet and reverted to a single mainsheet along with a pair of new oak jam cleats in the same locations under the gunwales where the thimbles used to be.
Modified the boat loading ramps so that each one has two wood stops that trap the gunwales better allowing single handed loading and unloading of the boat from the roof rack.
NOV 25, 2014
We went out Sunday, a rare sunny warm winter day with decent wind. The single mainsheet and oak jam cleats worked really well, simpler to setup and less line piled up in bottom of the boat. I can now load/unload the boat singlehandedly as expected. Pretty pleased with how things are coming together, about ready to make a 'real' sail thought the Tyvek one has held up really well and I don't feel bad modifying it as it is only temporary.
MAY 18, 2015
Just got back from the Anacortes Small Boat Messabout, great fun, great people, lots of boats. Picked up a few ideas and am modifying the rig so that it can be set or struck much more quickly. Will report back when I get a chance to try it out on the water. Looking at the pictures, the boat could use some weight in the bow to improve the trim. Going to add 2 gallon jugs of water to the boat kit.
I will add some new pictures when I get a chance.
AUG. 4, 2015
A number of minor changes made. Removed parrel beads from the boom and added a hook so that the boom hangs directly from the sail, the downhaul keeps the fork close to the mast. This also allows cleating the outhaul before raising the sail. The hoop is now attached to the halyard and a hook has been added, this allows hoisting the sail without having to tie any knots. The toggles attaching the sail to the mast below the yard are long gone, they were a pain to attach and performance is unchanged. I added a homemade aluminum sheave for the halyard to make raising it to the top of the mast smoother and less prone to jamming. A small cleat was added to the parrel beads and fork on the yard, no more tying knots! Added some vinyl around the mast near the boom as it seemed to chafe a lot, now quieter. All these small changes have added up to make Helium a lot easier and quicker to rig and to de-rig at the dock, a real convenience especially when it is windy and the sail is flailing about while you are trying to tie knots and adjust lines. Now the only thing needing attention after tying off the halyard is the downhaul, which I do tension fairly tightly in general.
Thank you for looking at Helium, if you have any questions/comments, you can e-mail me at firstname.lastname@example.org
© 2014 Alan Altman