Many years ago, Jim built Bolger's Birdwatcher.(Do a Google search on "Bolger's Birdwatcher" for lots of information.) One of the interesting concepts of the Birdwatcher design is that the cabin is almost the full length of the hull and is surrounded by clear waterproof windows on the sides and partially on the ends. The center of the top of the cabin is open as well as the center of the cabin ends. The result is that the boat can be laid over on it's side (on purpose or inadvertently) and no water will get into the cabin.
The boat is sailed or rowed from inside the cabin and crew is the ballast.
Since his time with Birdwatcher, Jim has designed a number of boats that include its concepts. One of those designs is "IMB". Using Jim's plans, I built this model.
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| Jim Michalak's IMB, a "Birdwatcher" Style Sail/Row Cruiser |
Modifications:
- Replaced the designed rudder with a Michael Storer style holster enclosed rudder that I've used on two of my sailboats (and will continue to use in the future).
- Added racks on the cabin top for spars (mast, boom and yard) for the lug rig sail and oars; required tie-downs not shown.
- Jim uses ropes to control the leeboard. Based on Jerome Delaunay's Scow 244, I decided to use a long handle to raise and lower the leeboard.
One of the advantages of building a model of your boat before you commit to the full sized boat is that you catch your own 'brilliant' ideas before you invest time/money in the full-sized boat.
For example, the handle on the outside of the lee board (as shown in the photo above) will NOT WORK on IMB. One would not be able to reach the handle without climbing on the cabin top (not a good idea) or by doing an awkward and dangerous stretch from the after deck.
The handle WOULD work if it were attached on the inside end of the leeboard pivot shaft. Thus the leeboard would be adjustable from inside the cabin.
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| IMB Showing Holster Style Rudder in the "Up" Position. Tiller extends under after deck about 13" into the cockpit. |
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| Oars Extended Through Oar Ports with Covers Removed |
Specifications:
- Length: 13' 6" (4.1 m)
- Beam: hull: 5' 3" (1.6 m)
- Water Line Length: 13' (3.9 m)
- Cockpit length: 8' (2.4 m) (bulkhead to bulkhead)
- Cabin top opening: 8' by 2' at midships (2.6 m by 610 mm)
- Span is 5' 3" (1.6 m); Oar's shown are 8' (2.4 m), which I believe are adequate for the small amount of rowing that would be done with this sail/oar cruiser.
- Freeboard: 1' 6" (457 mm), 2" (51 mm) less midships
- Water Line Width: 5' (1.5 m)
- WLL/WLW Ratio: 2.6:1
- Hull Speed: 4.8 Knots, 8.9 kph, 5.5 mph. Given the large wetted surface and low WLL/WLW ratio, sailing in good wind could reach these speeds, but not rowing.
Summary-Pros:
- Based on the Birdwatcher concept, IMB provides a safe and comfortable sail/oar cruiser.
- Oar ports enable her to be rowed (from within the cabin) when maneuvering in close quarters or when the wind dies.
- The lug rig provides a powerful sail that is set with little rigging and hardware.
- Plenty of dry storage in the 2 under-deck compartments.
- All sail handling, steering and leeboard control is done from within the cabin.
- Sailed heeled at 15 to 20 degrees (lee bilge panel is about horizontal), wetted surface would be reduced by approximately half and she would be really fun to sail.
- Able to be transported with a light trailer.
Summary-Cons:
- Rowing speed will be lower than "Hull Speed" noted above.
- Though plans are straight-forward, there are a lot of closefitting parts, especially around the windows and bulkheads, none of which are difficult to create and install, but do take more time to build than an open sailboat such as Jim's Mayfly series.
- The open top (and ends) of the cabin are really comfortable and safe in sunny/cloudy weather, but would require closures for inclement weather. Such closures are typically made with either waterproof cloth and/or hatches.
If we're looking for a comfortable and safe sailboat for both day-sailing (for a small family) and occasional overnights for one or two (very close friends), this would be an excellent choice that you could build for yourself.
Hi Tom - just curious, why do you prefer Storer's rudder? In my Cape Cod waters, there are many sandy shallows that only a kick up rudder and leeboard can navigate, whereas Storer's cannot without a lot of pulling and pushing. Am I missing something? As always, appreciate your models and ideas
ReplyDeleteHi Dryboater, Most of my sailing is in Barnegat Bay which means if you sail out of the channels, you can quickly run aground. In Storer's holster style rudder, the blade is held by the two sides of the holster (not sure if Mic calls it a holster, but it seems like a good name). The blade (the way I've made them) is attached to the holster in 2 ways: 1. One or two strands of of heavy duty (I use 1/4 inch) shock cord anchored on the sides of the holster and wrapped tightly around the trailing edge of the blade. 2. A light weight tether (1/8 inch line), 4-5 feet long, tied tightly to the top of holster and top of the blade as a safety harness in case the shock cord dies. When you run aground, the blade kicks up and then snaps back in place.
ReplyDeleteThe other advantage is that you have full control of how much rudder you want to have in the water: none if you are rowing or all the way down if you need lots of steering capability like on a broad reach.
Other than the pintles and gudgeons, no hardware is needed. The key reason's I like them is they are easier to make, little hardware needed and most important, I can control the depth.
One of the other things I've done with them is to add little wings on the bottom of the blade (which you can do on a regular rudder blade) AND wings on the bottom of the holster (which is level with the bottom of the transom) and controls the flow of water at the top of the immersed portion of the blade and the wings on the bottom of the blade control the flow at the bottom. I'm not sure if this really helps to make the blade more efficient (but gee, they work on a Boeing 777)
Sorry for going on and on about this, but I really like the holster!
Tom
No apologies called for it all, I appreciate all of your thoughts. They have been in Normas Lee helpful to me as an amateur boat builder. One question: when you say the Storer rudder kicks up, doesn’t it snap right back down and effectively anchor you unless you pull it up higher out of the sheath?
ReplyDeleteOuch should always read before hitting send! I meant “enormously”, not Nomas Lee whoever that is. Sorry!
ReplyDeleteYour models are great. Would you consider a post or two providing tips on how you build them? I've tried building a couple of models but they didn't turn out so good.
ReplyDeleteNice Post! This blog is so much attractive and the design is unique and looks attractive. In New Year 2023 will look forward to buy a yacht and go for a long vacations.
ReplyDelete