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Dave and Anke
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Saturday, December 7, 2019

Phil Bolger's BIRDWATCHER Concept

Photo by John Kohnen

A “bird­watcher” [is] a craft “in which one might poke through a marsh or backwater in search of nothing more than a pleasant lunch and a tan.”
-- Jack Dunn as quoted by Phil Bolger

Phil Bolger's BIRDWATCHER Concept

Phil Bolger introduced a true revolution in micro-cruiser design with his BIRDWATCHER concept.

A watertight, transparent super-structure is built upwards from the sheer of an ultra-shoal-draft, heavy bottom hull. Decks continue the water-tight integrity inboard to an elongated mid-ships companionway (which may be covered by removable fabric and/or hatches).

The crew is seated midships - the vessel's 'prime real estate', and low in the hull (vs. a raised cockpit) where their weight contributes to trim and stability. When standing in the 'infinite headroom' companionway, they are protected to well above hip level. 

The vessel is fully operable with excellent all-round visibility from the cabin where crew is protected from exposure. Dry shelter - whether at anchor or aground - is permanently available.

In a beam ends knockdown, such a hull floats all openings clear of the water, and is strongly self-righting from this position. A rollover is only possible when caught broadsides by a breaking sea.

A requirement peculiar to small, oar auxiliary boats of Birdwatcher lineage is that the “rig be quick enough to strike that one is not tempted to row with it standing.” Rowing via side ports is from within the cabin.

Core concepts:
  • Waterproof to above the knocked-down waterline (should float on its side without shipping water).
  • Long gangway running the length of the interior (mid-line security for standing crew).
  • Self-rescuing from inside the hull(!).
  • All operations possible from within shelter (no outside cockpit necessary).
  • Easily stricken rig (to reduce windage for rowing).
  • Reasonable performance under oars (eliminates expense, and weight of motor, and allows extended cruising away from fuel sources).


All (prudent) small boat sailors learn to right their craft from the water in case of a full knockdown. Chances range from significant to assured that they will use this skill, sooner or later. And then, we'd better be trained and geared up.

Wind gusts up. Attention lapses. We're in the water next to a half swamped boat. If the water is cold, the clock is ticking. Fast.

If the water is cold, the situation can be dire. If your gear is poorly stored, the situation can be dire. If conditions are bad, the situation can be dire.

It's hard to overstate the quantum leap in safety that the BIRDWATCHER concept affords the micro-cruiser.


Let's look for a minute at a full sized cruiser.

Can we sail (not just steer) the boat from within the pilot house? Are the lifelines substantial and higher than the hips? Can we recover from a full knockdown? Can we run it up on the beach? Trailer it? Row it at more than a knot or so? See out with an all-round view from belowdecks?

Maybe yes to a few of these, but seldom if ever to all.

Looking at micro-cruiser issues...

In micro-cruiser design, we juggle fixed shelter against the kind we must erect. Tent shelters are often high windage. They're often wet, hard to enclose and, once enclosed, to get in or out of. If we have to leave in a hurry, they're a bitch to strike.

If fixed shelter, we juggle against cockpit needs. Both compete for space. Both are pushed to the (usually tapering) ends of the hull. Crew weight pops up the bow or stern, depending on which end we're using. Certainly, we won't be steering, rowing or handling our rig from a cuddy.

And yep, if they blow over, we're back in the water.


In my Triloboat adaptations of the concept, the box barge foundation simplifies construction in the usual ways for the hull, and also for the window to hull interface (no bevels).

Oars present a challenge. When in use, the watertight ports must be open (risking flooding in a knockdown). They must be dismounted from inside or outside the cabin; both awkward. When let go, it's convenient to let them trail aft (Bolger solved this neatly with his port placement on BIRDWATCHERs' curved hull... but this limits rowing stations to one).

My solution to these issues is bent oars... they needn't be dismounted (stow in position), can be booted waterproof and trail alongside when let go.

Other designers - notably Jim Michalak - have employed BIRDWATCHER concepts in highly successful designs.

Full knockdown flotation and recovery test
in TRILOBYTE (T16x4)


NOTE: The BIRDWATCHER approach isn't the only successful one. Matt Layden and Sven Yrvind, among others, have successful designs (ballasted) for micro-cruising that answer 'yes' to the wish-list line items. These are ingenious balances of more traditional approaches.


  1. "Revolution in microcruiser design" is right. In Bolgers "Boats with a Open Mind" book fun to see him apply the concept to 3-4 largish cruising designs.

    Some folks seem more tolerant of tropical sun than me but the birdwatcherized cockpit makes TOTAL sense in avoiding the deadly effects of solar radiation. In Florida we'd get massively baked from reflected rays despite a giant bimini. We'd have to put on side curtains and the birdwatcher cabin does this automatically. In addition Jim Michalak points out that the back draft wind currents off the sail funnel down into the slot top for natural fan like air conditioning. And hard to argue with strolling to the bow, on smaller boats, with the upper 1/3rd of your body out the slot top and secured from any falling overboard. For folks in larger cruisers even birdwatcherizing the center cockpit is totally worth it.

    It's like folks who can't see the benefits of shoal draft over a keeler: abstract until experienced then there's usually no going back.

    Bolger deserves well written posts like this to keep his wonderfully unorthodox thinking alive and celebrated.

  2. Hi Roberto,

    I can sure see both the protection and the occasional need to escape the 'glass house' in warmer climes.

    Opening, doggable windows are less KISS, but can help. I do remember Bolger writing of them and the oar ports that he'd "make a fetish of keeping them closed while sailing."

    But yeah... what a hoot!

    Dave Z

  3. 27 years of Birdwatcher ownership. Many modifications, some approved by Phil before he died, others he didn't support. Hard to explain to traditionalists why we love this boat. And if you think other sailors don't appreciate this design, just try explaining to casual onlookers at boat ramps and beaches.

    1. Hi Mark,

      Thanks for writing with the voice of experience!

      I'd love to hear more about the changes you've made and how they've worked out... would you care to share?

      Phil's BW, with it's pronounced aft curveature to a pointy end, allows one pair of oars to trail when released (so bent oars not needed). But they still seem the weak point to me, handling in gusty, up and down weather...

      Have you tried booting them, or not felt the need? How well has shipping them worked out for you?

      Congrats on your early, fine choice of vessel!

      Dave Z

  4. Haven't built one yet. Like both the trilobyte and also IMB and jewelboxes (from Michalak). Will probably build the IMB. Simple and lightest. Still like the trilobyte, juts not sure about enter and egress for passengers. Birdwatcher is the only concept worth building, given all the other options.

    1. Hmm... entrance and egress.

      From a dock, these are a lot lower than one would expect.

      Dried out or from the water, there's more challenge. In TBYTE dried out, both ends are an easy long step or short clamber. In the water, the rudder flanges provided a stand-up step.

      Or rod can be threaded at both ends and bent to form a squarish U... like a staple. Or aluminum plate bent to form a right angle step and strut. Then bolt to the hull at convenient heights and locations. The plate, especially is low drag if immersed.

      In boats with gunnels, a gasketed, doggable door can lower the sides.


      Lots of options in this ol' world!

      Dave Z