Skin-on-Frame boat for oar and sail?

[overland]

I have a 15' modified Swampscott dory that can hold two people and is nice at both rowing and sailing, though no speedster at either. I've used it for both. Now I'm trying to replace it with a lighter SOF boat. I've found two designs. One is Dave Gentry's Annabelle Skiff (10' x 4'); the other is Monfort's Classic 12 (or 14) Geodesic boat (12' x 4' or 14' x 4'). Has anyone built either of these boats and is in a position to comment on them? Are there others that I should consider? CLC's Skerry looks like it fits the bill, although of course it's not skin on frame. I'll be grateful for any thoughts.

[skuthorp]

WB No. 272. Pge 22
Modified Geodesic Boats Classic 10 by Steve McMahon.

The article has made me think of building one, The frame looks so good I'd be hesitant about skinning it.

[johngsandusky]

I haven't built any SOF, but I think I could convert many designs to the method, or a hybrid like ply bottom and decks with skinned sides. You might look for your ideal design and see if you can build it SOF.

[Hull Speed]

Regarding the Classic 12, I built one years ago and although I got several years use out of it, I would not build another boat using this method. The 3.7 oz fabric is much too light and tears easily once painted; also the epoxy joints between the ribs and the stringers began popping soon after the boat was built, a problem that finally led to the boat's demise. This might have been my own incompetence - I have never gotten on well with epoxy - but I've been much happier with my latest boat, which is lashed.

As for the Classic 12 itself, on the plus side it was light enough to carry 2 km through the woods but still stable enough to stand in and pole up a shallow creek. As a rowboat it was quite slow, and as designed it would not hold its head to the wind without a bucket of rocks in the bow. This made for some very tiresome one-armed rowing. Cutting away half the skeg did solve this problem, however. As a sailboat, I used a standing lug (contrary to the plans), and only sailed when the wind was too strong to row. The only comment I can make is that crew placement is important in any small boat but especially so in a very light boat, and in the Classic 12 I found it hard to get far enough forward to keep the bow down.

Ken

[skuthorp]

Interesting comments Ken, especially about crew/weight placement. I have always wondered about windage, flex and longevity of the skin. I sail in a large shallow bay with a lot of sharp volcanic rock and decided SOF are not suitable.

[jtdums]

Interesting comments Ken, especially about crew/weight placement. I have always wondered about windage, flex and longevity of the skin. I sail in a large shallow bay with a lot of sharp volcanic rock and decided SOF are not suitable.

Sharp volcanic rock might worry me a bit too, but I know from experience the Gentry boats spec a heavier weight skin that is really surprisingly tough. The Montfort boats always seemed to push the lower weight limit a bit to me. I'd rather a few more pounds overall and the security of that thicker material. For the record I have not, however, built the Annabelle skiff nor can I speak to its performance.

The CLC kits are a pleasure to work with as well. (I just finished up a Kaholo SUP). Well thought out and they make the build really fly along if that is a consideration.

[Ben Fuller]

Boats that are skinned with poly and use the two part mix from Corey Freedman are very very tough where as Platt's boats are meant for lighter use. Some of them like the Classic series can benefit from a forward seat when carrying passanger's. Dave Gentry has done the most I think with SOF for oar and sail although Brian Schulz of Cape Falcon has done several. Flex is an issue when you put a sailing rig into them.

[upchurchmr]

Ben,
Why mislead this guy?
Corey's boats are probably 8oz material while Platt's boats are 2.5oz.
That is the reason for the toughness difference.

Corey's goop is good but not the major reason for the toughness. It's also difficult to apply smoothly.

[The Jeff]

Here's an interesting webpage of a guy building a 12' x 4' SOF boat that is based on a Delaware Ducker from Chapelle. Not sure how much "winging it" you want as he added freeboard and rocker, but it looks interesting.

https://sites.google.com/site/helium12sofsailboat/

[Woody Jones]

Paul Gartside's Dispatch is a good looking sail and oar boat and could be built skin on frame. 14' x 4'8". Free plans are available in Water Craft magazine No 94 July/Aug 2012. I believe old issues can be purchased. The plans are pretty basic so you'd have to figure out a lot of the details yourself.

I'd reduce the sail area considerably and and use it for reaching and running only to reduce stress and flex on the frame.

[Ben Fuller]

Ben,
Why mislead this guy?
Corey's boats are probably 8oz material while Platt's boats are 2.5oz.
That is the reason for the toughness difference.

Corey's goop is good but not the major reason for the toughness. It's also difficult to apply smoothly.

No need to get snarky. I knew Platt and used many of his boats. Very light weight and he would admit it. Fabric was good against a hammer blow but you wanted to get out before you hit a Maine beach. I've also broken one of his high speed sailing dinghies, driving it hard in a breeze, I was planing pretty quickly at the time. General disintegration of partners, mast and step. I was hiking at the time. Fun.

I've done I think 4 kayaks with poly and goop. Highly abrasion resistant at least in my application, Maine rocks. Hitting a sharp glacial rock at 4 knots or better may cut the fabric and I have a couple of cuts I have fixed.

Applying goop is indeed not as easy as paint. It is tougher and systems have been developed to make it easier, notably the use of rollers. Schultz at Cape Falcon has a pretty good free video on it. Where I think the goop excels is the abrasion resistance but you are correct, the strength is in the cloth.
I know he built a sailing version of Joel White's larger Shearwater and a sailing ducker. He took the Shearwater dwn to Baja, where it was OK, but had some rigidity issues due to a big load and the sail. Long story in WoodenBoat. We worked on that for the ducker, using a ply deck to pick up the mast and dagger board loads.

Platt wanted a rigid frame based on his aircraft building experience, hence the kevlar strands. I'm not so sure that in light weight that is good. The lashed frame boats seem to have some useful flexibility.

Of Gentry's designs, the 13' melonseed is well proven. The deck gives you the seaworthiness and rigidity needed to carry sail.

[skuthorp]

The kevlar lashed SOF sea kayak I borrowed for an afternoon had an unsettling amount of flex in the 3-4 ft swell. May not have been tightly enough built.

[Dusty Yevsky]

Here's a sail-and-oar SOF suggestion from left field. Wooden Widget's Fliptail. I recently built a Fliptail 9 and have rowed it a few times and it rows well, at least in my un-expert opinion. It has the most room of any 9' dinghy I've ever seen. It could easily handle three adults or two adults and two kids. I built the sailing components but haven't had a chance to sail it. It uses an Opti rig and boards so all the goods are easy to get. Oh, and it folds up to a compact package easily lifted with one hand.

https://www.woodenwidget.com/fliptail.htm



Just for the record, Monfort's designs and kits are now offered with 9oz dacron in addition to the 3.7oz.

[4lexander]

I built a Classic 12, and I love sailing it. The light weight makes it possible for me to have a sailboat that I can keep on my property without a trailer, so the weight is more about what happens off the water than on. I love it although If I could start over, I would build the 14ft model. Two adults are pretty tight in there, but I once rowed three adult and a kiddo in the bow around a lake. Changes I recommend: Maybe heavier fabric, Definitely use the 2 part Urethane goop, tie the ribs like a kayak.

[johngsandusky]

Welcome aboard 4lexander!
I have recently sailed my rigid Folbot Super. It's 17.5' x 37", about 80# and remarkably stable. In this case it is old school SOF: two layers of vinyl over web frames and stringers.

[4lexander]

Thanks! I've lurked around here for years, and now I am sure I should have signed up BEFORE I built a boat. Folbot looks like a great multipurpose boat. Those lee boards are a little scary looking though.