James McMullen's Rowan, an Oughtred Snooty Tern

[keyhavenpotterer]

You don't want a stiff one to be well hung on a balanced lug: you can go harder and faster with a floppy one so long as its well held.


Dad had carbon spars on his balanced lug rigged 12ft Scow for racing. It was certainly lighter, but with the sail track and blocks and line etc it loses some significance, but it was lighter, which has its advantages raising and lowering, and while sailing. It had structural foam in the ends to seal it and then some mast plugs and kevlar spiral wrap in places to to keep the carbon in alignment and provide abrasion resistance where needed.Conventionally you want a stiff mast (the sail was designed for use with stiffer aluminium spars) as if it bends it reduces luff tension, as the distance from downhaul attachment to sail mast head block reduces a bit. All bad on a lug. But in practice he found the slightly soft carbon mast would bend outwards on the 'bad tack' in medium to heavy air (top was held with shrouds/ forestay) away from the sail before it went really stiff, leaving a unimpinged airflow over the sail luff and he could sail faster and higher in the races on that tack than other boats, into the lead and win races. Dad was adamant that it he was faster sailing along with his flopping out, that this was a bigger gain than the reduction in luff tension on a balanced lug. Others were too conservative to believe it but he had the trophies. I guess if you take it to the extreme you'd purposefully make it quite floppy (like windsurfer masts are), then pre tension it stiff like a bow with your downhaul (like windsurfers do) as you hang your lug sail from it (where the string would be on your bow and arrow). But it would be assymentric and look a little unusual (but you'd win races), and you have to have a boat/ sail plan that can accomodate shrouds/ forestay, and the lug still swing. They weren't windsurfer masts, they were 'proper' carbon/glass tubes from http://carbonfibretubes.co.uk/custom.html and cost quite a bit.

We worked out the weights, I think aluminium works out half the weight of solid wood, and carbon is half the weight of aluminium as a bare tube. I think for price aluminium is cheaper than wood, here in the UK and where the sweet spot is for price and performance. Being untapered though the tubes look less aesthetic than a tapered one at the mast head. Adding shrouds reduces the required mast dimension and saves weight too whatever the material. How stiff they are no doubt is also affected by how they laid up too and the fibres are orientated but you can also make your own carbon masts using a cheap aluminium tube as the mandrel and make it custom. http://www.devboats.co.uk/cherubweb/masts.htmEd

[James McMullen]

Shrouds are anathema for sail and oar. Not doing that. I have been researching carbon fiber spar construction methods though. And I even already happen to own the tools to vacuum bag it. This might well happen. I'd probably start with building a yard before going to the mast itself.

[Yeadon]

Shrouds are anathema for sail and oar. Not doing that. I have been researching carbon fiber spar construction methods though. And I even already happen to own the tools to vacuum bag it. This might well happen. I'd probably start with building a yard before going to the mast itself.

Let's do a carbon fiber mizzen mast for Big Food. I had a friend over to the house recently who walked me through the process. It sounded pretty do-able.

[IanHowick]

A way to get lightweight spars for these sail and oar boats that isn't often mentioned is to get the professional spar makers to wind pre-preg glass-epoxy on their spar mandrels. Typically you can manage weights of half that of a hollow wooden spar at some very reasonable prices. (Carbon-epoxy can come out at about one third the weight of a hollow wooden spar, so the weight difference between carbon and glass can be around 30-40%, for a price difference of 600-700%)

When you look at the numbers for stiffness to weight, glass-epoxy composite isn't much different to wood or alu, but you are in a position to optimize both overall spar taper and wall thickness, which produces big weight savings. As an example, I got a mizzen mast done 3.4 m long, tapering 55 mm OD at the base to 30 mm OD at the tip, 2.5 mm wall at the bottom, 1.5 mm wall at the top, all for about US$100. 2.0 kg all up, half the weight as the same outside dimensioned wooden mast. Stiffness is about the same as a 55 mm solid wooden spar, but strength is about three times as much (the glass will bend much further before it breaks)

Depends of course on having a friendly spar manufacturer, but I have found more than one in NZ prepared to do one off carbon or glass spars in these sorts of sizes. Freight to somewhere else in the world isn't that pricey compared to inter-country freight. A big advantage of importing from another country is you avoid the GST/sales tax in the exporting country and usually avoid tax/duty when it comes into your country. A fellow in the UK ordered an identical mast to my GIS main mast from my NZ manufacturer, it landed in Norfolk for about the same price mine landed at the other end of my own country.

Ian

PS

I'd be curious/doubtful as to how good an amateur job you can do on a carbon spar, I've seen lots of blogs of people doing so, but little in the way of good comparative data on how heavy the spar turned out, and how stiff and strong it really is. Of course it's not possible to accurately determine ultimate strength of a homemade spar without breaking it, but fairly accurate weight and stiffness data should be easy to report.Perhaps someone like James M with previous experience in carbon composites and the set-up to do vacuum bagging can get it right, I'd also be curious as to how he'd go about it. (Mandrel or foam core with linear carbon sleeve like this over it, resin and vacuum bag or shrink wrap?)

It would be easy to end up with something expensive that is heavier and weaker than ideal. Too much resin overall and not enough at a critical point near the mast partner and it could all come tumbling down on you.

[BBSebens]

Let's do a carbon fiber mizzen mast for Big Food. I had a friend over to the house recently who walked me through the process. It sounded pretty do-able.

You guys do it and make sure you post a good thread. Im sure many of us would be very interested to see how it turns out.

[James McMullen]

Okay, I've done a few upgrades and mods to Rowan for her 6th birthday, and this seems like a good thread to document them. First, she's got a new cockpit tent and center thwart mod to make it easier to sleep aboard. Here's the hinged thwart:



And here's the tent:



I also made some dedicated fitted cubbies to hold binocs, GPS, compass, flares and horn under the port side bench where they'd be right to hand whether sailing or rowing. I made them in a simple epoxy filleted plywood style, with rubber sheet cemented to the bottoms to keep stuff inside from sliding around.

[James McMullen]

And then she also got some new paint inside and out. I decided to change the interior color to more of a "linen" tone off white, and the sheerstrake accent color from that dark blue to a more subtle green to better reflect the color of the sea.





And one of my shop assistants graciously helped paint the mahogany side benches for me one night.

[potomac]

Those cubbies are great, James. A place for everything and everything in its place. The paw prints are pretty funny. You're a sport. I think were it mine, it would have been downgraded to "outside cat" status.

[jsjpd1]

I like that cubby idea a lot James, I my just have to borrow it.

Jim

[davebrown]

(IF I RECALL CORRECTLY...) Are you still painting exterior hull with latex? I like that idea, but everytime I research I find a flood of negativity about it.

[TerryLL]

I like that cubby idea a lot James, I my just have to borrow it.

Jim

Yup. I'm borrowing (stealing) that little detail.

[James McMullen]

(IF I RECALL CORRECTLY...) Are you still painting exterior hull with latex? I like that idea, but everytime I research I find a flood of negativity about it.

I have spent the last week or so at the shop prepping and painting a 40' yacht with longboards and microspheres and coat after coat of HVLP sprayed primer and fine grit hand sanding and solvent wipe tacking wearing a Tyvek coverall and carbon filter respirator and gradually losing the will to live.

I ain't doing that sh*t without pay. Not for my hobby, fer chrissakes!

Small boats are not the same as big boats that stay in the water all the time. Latex exterior house paint works just fine for a workboat finish on a small skiff or rowboat. And you don't have to worry about dissolving your fingerprints right off if you get some of the thinner on your hands. Just let it cure for a good week or two before you splash.

[Rob Hazard]

Those cat prints are wonderful! I hope you've left them there.

[James McMullen]

Those cat prints are wonderful! I hope you've left them there.

I did. I find them absolutely hilarious!

The only question is whether to sand them off when it's time for new varnish or to coat right over them to preserve them for posterity.

[wizbang 13]

That there is a fine boat evolving .

[htom]

Hmm. I wonder if it would be possible to mold a thwart substitute, a pair of braces that would start at the gunwale, flow down the inside of the hull, and then up the centerboard?

Coat right over the cat footprints. They're hilarious and precious.

[Breakaway]

[QUOTE]And one of my shop assistants graciously helped paint the mahogany side benches for me one night.

[/QUOTE

James, consider making that Emerald Marine's trademarked non-skid pattern. " Keep your feet like a kitty, even when the water's sh!tty"

Kevin

[BBSebens]

Its hilarious that the cat stepped right over the thwart. I'd lay a coat over them now before you rub them off while using the seats.

[neilm]

Okay, I've done a few upgrades and mods to Rowan for her 6th birthday

Outstanding ideas James! That tent idea looks very simple, compact and opens to leeward so it should be fairly dry. I suppose you could always use the mainsail for a tent in a pinch. I may have to copy the cubby holes too.

Do you have any construction photos? I am somewhat struggling with the keelson/keel concept. I'm working on my stems now.

Neil

[James McMullen]

Neil, I'm afraid that before I had a camera built in to my phone, it was a rare occasion indeed when I took any pictures. And even when I did, the early ones were film, not digital, and therefore a royal pain to upload. So I don't really have very much for you on Rowan's construction. But the step-by-step pictures in Oughtred's Clinker Plywood Boatbuilding Manual are top notch and should help.

If you want more info on the design and construction of that tent, though, check out this thread: Designing a Cockpit Tent.

[potomac]

James, If I've missed this information somewhere in this thread, then I apologize for the redundancy. Much is made of the Caledonia Yawl's load carrying ability as well as her potential difficulty rowing and yet, the Sooty Tern isn't tiny. I'm wondering, if the design brief were to remain very similar (i.e. sail and oar, proficient as a rower, never going to utilize a motor, quick at the dock, and able to be singlehanded), but going to change in that instead of one or occasionally two passengers, it would almost always be three on the boat, and instead of camping as much, it would be more day-sailing with an occasional single overnight, would Rowan still be your choice? Recent experiences with motors and rowing have brought this question more to the forefront for me. I really enjoy the quiet and the less muss and fuss aspect, but I also really like the ability to be able to get in the water for even four or five hours without a lot of hassle.

[James McMullen]

I think it's not really that much of a different load with one guy and a week's worth of camping provisions as three folks and an empty boat for daysailing. And she handles fine either way.

Yes, Rowan would still be my own choice, but as you mentioned, she is not at all a tiny boat, and some are content with a somewhat smaller boat like the AT. I think Rowan is near the maximum size for comfortable long-distance rowing by one if you are not fairly hale and hearty. But the CY is definitely over that line. You could set up a ST for rowing double without any trouble if you planned for it from the start. And rowing for shorter distances is no trouble at all.

A CY is a full foot wider than Rowan, and is also deeper and higher-sided. None of that helps at all for ease of rowing. Here's a picture of Rowan side by side with a CY and a Hvalsoe 16 which shows relative sizes. The Hvalsoe is the best rowboat, and the CY the best load carrier under sail. And my baby is in between.

[Yeadon]

That's a Hvalsoe 13. If you can't get such a simple detail right, how can we believe anything you write?

[James McMullen]

Caveat emptor, me hearties!

And who says I need people to believe me, anyways? I'm just happy to have them pay any attention to me at all.

[jsjpd1]

That's a Hvalsoe 13.

The CY looked bigger when I thought it was a 16.

[WI-Tom]

James,

when you took me sailin' at Port Townsend we had three aboard and plenty of room for daysailing. Your boat feels REAL big to me. Not bad, but big. That opinion may evolve as I move from my old 14-footer to my new 18-footer this summer. But I hardly think you need a CY to daysail with a few people; your boat seems to do that just fine.

Tom

[callsign222]

James,

when you took me sailin' at Port Townsend we had three aboard and plenty of room for daysailing. Your boat feels REAL big to me. Not bad, but big. That opinion may evolve as I move from my old 14-footer to my new 18-footer this summer. But I hardly think you need a CY to daysail with a few people; your boat seems to do that just fine.

Tom

Real quick, what are you swapping into Tom? I got distracted by the Pheonix, I thought that was where you were going next, but it's not 18'.

[WI-Tom]

Real quick, what are you swapping into Tom? I got distracted by the Pheonix, I thought that was where you were going next, but it's not 18'.

The Phoenix III is my brother's boat. My new one is Don Kurylko's Alaska:

http://www.dhkurylko-yachtdesign.com/designs.htm

I'm just about ready to start gluing in furniture:



Tom

[callsign222]

Oooooh hideous! You better pull that over to my house and spare your neighbors the trash you're leaving out front.

[Eric Hvalsoe]

The CY looked bigger when I thought it was a 16.

I so want to apply all the noodling on my 16 to an 18, give or take.

My new spruce birdsmouth mast for soon to be lug main, about 12 lbs unfinished. That still feels heavy to me, in the low slung 16. It has 1/2" wall which I now think is totally overkill. 3/8" and I'd have a spar of less than 10lbs. Birdsmouth yard, 3/8", about 9 ft and 3.5 lbs.

ah . . . great thread!

[keyhavenpotterer]

I'm quite a fan of the 16'10" Oughtred Tirrik. The sail plan is a single balanced lug or gunter sloop. Those hankering for a lug yawl, but in a shorter and lighter length, could look at this one built by Grape View Point Boat Works.

Its the first one I've seen sporting a lug yawl rig. Whether Ian has drawn this now or whether it was a one off (also purchasing the Arctic Tern plans will give the idea of the lug yawl sail plan rig and location) it looks good. The shorter water line length, wave making resistance and weight of the Tirrik all helps its rowing performance under single oar power. It will have slightly lower top speed than Rowan, but not by much, and a bit less carrying capacity, but its still designed for the weight of two people and a bit of gear, so a solo sailor will still have approx 100kg for ballast and stores. Being 4 strake it will be quicker to build, and the floors etc simpler to fit accross the garboard.

Its drawn with 5'4" beam like Rowan.










http://grapeviewpointboatworks.com/b...k-is-complete/


Ed

[Eric Hvalsoe]

Very nice boat. Content I see to sheet the mizzen off the rudder. I was about to blather on about rig types but after this season I'll be able to compare different rigs on the same hull. James' thread anyhow.

[Gerarddm]

How very strange to rig off the rudder and stem heads. Have never seen that before. Not sure I like it.

[Paul Pless]

James' thread anyhow.

ahem

[keyhavenpotterer]

Taking the mizzen sheet to the rudder head is how Ian draws it on the Arctic Tern. The CY is drawn with a boomkin out from the stern, but Ian draws the smaller ones this way.


I've no experience of it personally, but I've read people finding excessive sail twist occurs as the mizzen sheet is eased, but that could be sorted by fitting a proper kicker easily enough, provided it has room to swing over the tiller extention.

Ed

[WI-Tom]

Of course you do need some kind of rudder hold-down if you sheet to the rudder head. Not that I know this from experience or anything...

Tom

[James McMullen]

How very strange to rig off the rudder and stem heads. Have never seen that before. Not sure I like it.

I am quite certain I don't like it. That's how I originally rigged the Ness Yawl Dragonfly, and it was experience with that and the results of Chad's experiment mounting an aftermarket boomkin to the gunwales which led me to incorporate a boomkin into Rowan from the get-go.

The problem is not the rudderhead location per se, it's the mid-boom sheeting that the too-far forward location that the rudderhead imposes. There's simply far too much slack in the system to get the sail hauled perfectly fore and aft when you want to heave to. A boomkin that leads a sheet out to the very end of the mizzen boom has far greater leverage and offers better control.

I also like the look of the "stinger". It's purposeful and olde-timey at the same time.

Why people leave the boomkin off is to save the effort of making one more spar, but the rig really does work better with a boomkin.

[James McMullen]

And while it was Paul that started it, and Rowan that's featured in it, I certainly don't mind if anyone wants to chime in on sail 'n oarey stuff on this thread whenever they want.

So blather away, Eric! There's plenty of precedent, and you're in great company!

[Osborne Russell]

Would it help to lead the mizzen sheet from the end of the boom rather than the middle?

[James McMullen]

There's still more rope than ideal in that situation. Rope is stretchy. And it's not at an advantageous angle for leverage, either. The best leverage is found with the sheet attached right at the clew. A boomkin will give you the shortest run of rope led directly from the clew.

[keyhavenpotterer]

It needs a magazine called Sailoar.

[Wayne Jeffers]

Something I've been trying to sort out for this design (or for the Arctic Tern): If you're sailing with several friends, have you found a way to stow the oars so that they don't interfere unduly?

It seems to me that the bulkheads for the watertight compartments fore and aft would preclude stowing the oars below the side benches. (At least if the oars were a useful length.)

The best I can come up with would be to stow them atop the foredeck and the thwart, leaving only the back half of the side benches unencumbered. Have you come up with a better solution?

Wayne

[TerryLL]

Something I've been trying to sort out for this design (or for the Arctic Tern): If you're sailing with several friends, have you found a way to stow the oars so that they don't interfere unduly?

It seems to me that the bulkheads for the watertight compartments fore and aft would preclude stowing the oars below the side benches. (At least if the oars were a useful length.)

The best I can come up with would be to stow them atop the foredeck and the thwart, leaving only the back half of the side benches unencumbered. Have you come up with a better solution?

Wayne

Same question I have for dealing with 10' oars on a decked Caledonia Yawl.

[Scott de M]

A couple options for oars that I use on my Caledonia are 1) install oarlocks for an additional forward rowing station (I would recommend this in any case), and then leave the oars in the locks with the blades crossed in front of the mast. This leaves all of the benches and thwarts clear. I guess if you dipped a rail violently it could dislodge an oar but I use captive locks and this has not been a problem yet. 2) I cutout the bracing at the front of the centerboard case so that the blades of the oars can slide through with one oar on each side of the CB. This works quite well once the oars are in place but it is not quick to get them back out should an emergency arise. Also I do not have rear decking so I can't say for sure that this would work in every case.

[Eric Hvalsoe]

You don't want a stiff one to be well hung on a balanced lug: you can go harder and faster with a floppy one so long as its well held.

I was wondering what this fragment from post 601 was about.

Regarding stowing oars . . . on my 16 (transom stern)
I will sometimes store them at the rails in the two sets of oarlocks, I call that torpedo style. Blades aft, just as you would ship them. I leave a short length of line hitched on the rails to lash the oars securely.
When alone under sail I prefer to set the oars in the forward locks, and run the handles all the way to the stem, tucked under the breasthook, again lashed to the rails. When 'cruising' I often bring a 2nd set of oars, even if solo. They may never be used, and live on the floorboards tucked up snug to the trunk with the handles run all the forward - the handles nest in short pvc sections of tubing at the bottom of the forepeak/chain locker area (in other words, about where the stem knee is). I use 8's.

[James McMullen]

I just stick the oars out in front. I don't find them much in the way. Boat's plenty long enough, and unless it's really howling, you're not going to sit all three on the same side anyways, so they're really not onerous to deal with by keeping them close to hand for quick deployment like this.

[jsjpd1]

I just stick the oars out in front. I don't find them much in the way. Boat's plenty long enough, and unless it's really howling, you're not going to sit all three on the same side anyways, so they're really not onerous to deal with by keeping them close to hand for quick deployment like this.

We store ours like that on our CY too, and they generally aren't in the way four our crew of four, but they are easy to get at. Of course, we use thole pins so storing them in the oar locks is out.

Jim

[Wayne Jeffers]

James -- That's pretty much what I thought, but I couldn't tell for sure how much of the side benches were clear of the oars. Your arrangement seems entirely reasonable.

Eric -- Torpedo style would clear out more of the interior and keep the oars reasonably at hand. That too sounds like a good solution. But instead of line for lashing, I would probably be inclined to use nylon webbing with Velcro. I use 1 1/2-inch webbing and Velcro to stow oars on my outboard skiff and I have found it to be very secure.

Wayne

[Eric Hvalsoe]

My boat is smaller than a CY, Rowan etc. Just setting the oars inboard on the thwarts is pretty much in the way. When solo and sailing to windward I sometimes park on the floorboards ahead of the main thwart. Either facing forward, or thwartship with my legs across the trunk, my back against the hull. This is reasonably comfortable and leaves no room for a side bench midship, or a set of oars inboard. Different boats, different solutions. Most out of the way for me seems to be forward locks, handles to the stem.

Velcro works

[Yeadon]

I kept losing my oars overboard when I went torpedo style. I'd dip a rail too often and one would just float away, or they'd get knocked askew when I dropped the yard. So now I plug the blades into the forward oarloack on the starboard side, run the handles up under the breasthook, and lash the whole thing down with a bungee. Works fine, and they're always there when I need them.