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Fair winds!

Dave and Anke
triloboats swirl gmail daughter com

Thursday, April 12, 2018

A Look at Box Barge/Scow Sailing

SLACKTIDE sailing to windward in about 20 knots of wind.
For some reason, the fairly extensive white caps didn't show up,
and I apologize for the wind-in-mike effect.

If a pitcha's worth a thousand words, how much fer a movin' pitcha?

A Look at Box Barge/Scow Sailing

If one were to go looking for some video of cruising-sized, box-barge/scows under sail... well... it's thin pickin's.

Despite the fact that sailing barges and scows once carried a good deal of freight in Europe and North America, very little information as to how they sail is readily accessible (okay... google, right?).  One can only infer that their numbers prove they must have been able to compete against curvy dog rivals.

We had extensively sailed LUNA, a fine sailing hull modeled on Phil Bolger's AS29. It's a square sharpie... much like a barge, but with ends pinched in. It's full rocker sets it off from the large, mid-ships deadflat that help keep Triloboats relatively quick and easy to build, and was a common feature of the sailing barge/scows of yore.

We reasoned that the barge/scow form couldn't lag too far behind. But as a precaution, we built SLACKTIDE as a proof-of-concept before committing to WAYWARD, a full-sized liveaboard cruiser. After all, sailing engineless in SE Alaska, ya need to be able to get out of yer own way!

To make a long story short, box barge/scows sail reasonably well. We've had no problems going anywhere we wish, and that involves many places and situations most wouldn't care to take their sailing home, no matter its capabilities.

Things I note about box barge/scow hulls:
  • Heeled, they present a V to the water.
  • Upright, their entry is rather fine (directing water downward for lift, rather than parting to either side... this is true even with relatively abrupt bow curve).
  • Easier aft curves release water well and make for an easier driven hull.
  • More abrupt forward curves don't seem to hurt, and do seem to reduce pounding.

The videos embedded here allow a look at how three models sail. Cast of Characters as follows:

SLACKTIDE (26x7x1) is a Triloboat Junk cat-Ketch with rather abrupt end-curves, intended to prioritize carrying capacity over speed.

SPIRIT (36x12x?ft) is a Civil War Cargo Scow gone Blockade Enforcer, with easy lines prioritizing speed.

ALMA (60x22x4 is a San Francisco Hay Scow Schooner. Her lines are quite abrupt with a long deadflat, prioritizing heavy lading.

So here ya go... a movin' pitcha look at box barges under sail:

SLACTKIDE running under reefed sails in confused seas

SLACKTIDE close-reaching in light air.

SV SPIRIT sailing on several points.
Note the view of the bow waterline... not much fuss.

This hull, compared to the others, is a relative pig to handle, 
yet comes about slow but sure.


  1. Thanks! They quicken the heart just a bit.

  2. Hi Sixbears,

    Thump-a, thump-a! Us too! Can't wait to finish up and get some sailing in. Coupla more weeks!

    Dave Z

  3. Replies
    1. Hi Shemaya,

      Glad you like!

      Hopefully we'll get some vid, soon of WAYWARD coming about. She tacks quickly and reliably (with half her length in deadflat).

      Dave Z

  4. What a pig the Alma is coming about.... makes a case for some rocker. While in Florida about 2 years ago I sought out the Spirit and when no one was looking jumped aboard (no one aboard, of course) and walked about. What a beautifully lined vessel. Brings to mind visions of civil war blockade running on a new moon night blasting over shoals, cannon fire receding off in the void. VERY romantic vessel.

    1. Hi Robert,

      Increasing rocker (shortening deadflat) definitely makes a boat more nimble (quicker, coming about). As with all things, though, it trades one virtue for another. In ALMA's case, quick tacks were of lower value than her enormous load-hauling ability.

      Ditto her relatively low length-to-beam ratio of about 2.66 to 1 (as I recall). I prefer 4+:1, and consider 3:1 the lower end for box boats who want to sail in general conditions.

      And yes, S/V SPIRIT trades at the other end... less hauling but better sailing qualities.

      Comparing the two, I wonder if ALMA - whose sailing grounds are the Sacramento Delta and SF Bay, required less ability, while SPIRIT - sailing not just rivers but the open Florida coastlines - needed more?

      Both cases fascinate me as working vessels thriving in direct competition with Curvy Dogs.

      Dave Z

    2. 5:1 sleekster, 12:1 trilo-proa. From viewing model testing of barge shapes it seems slight rocker might be worth it on a barge sailer. Take something like Loose Moose 39 and just open the ends to barge square shape and reduce rocker a bit and perhaps the best of both AS and Trilo worlds.

    3. Hi Robert,

      I agree that slight rocker in place of a deadflat is something to consider. It certainly adds rigidity to the bottom, and may well result in an easier driven hull.

      The main advantage of a deadflat is simpler construction, mostly in matching vertical elements (sides, furnishings, bulkheads) to the curve. Not rocket science, but it adds time and material.

      The end curves are a significant departure from AS hulls, however. At both ends, squaring out to a rectangle in plan (top) view) means that the ends need to be carried higher to avoid plowing/dragging when heeled.

      A side benefit of a high, relatively abrupt bow curve is that it reduces pounding. The low AS bottom curve angle is easily reached by waves while sitting upright in an exposed anchorage. Like two hands clapping, a boom results. The higher barge ends only match wave angle in extreme conditions. Even then, the greater arc at the short ends quiets the whump.

      In our experience, AS pounding at anchor occured only rarely, when considerable wind came up in exposed anchorages. We have yet to hear steady pounding in the barges (no more than we've heard in Curvy Dogs). The bow is more 'talkative', but is more the cheery riffle of a small stream.

      Dave Z