Sunday, April 30, 2017

Bolger's Cartopper

Using the plans published in Bolger's book, Boats with an Open Mind (page 25), I built a model to illustrate how Cartopper could be converted to an Oar Cruiser without changing the hull shape.

Specifications

  • Length: 11' 6" (3.5 m)
  • Beam: 4' (1219 mm)
  • Weight: 90 pounds (40.1 kg)
  • WLL: 8' 11" (2.7 m)
  • WLW: 29" (732 mm)
  • WLL/WLW Ratio: 3.7:1
  • Hull Speed: 4.0 knots, 7.4 kph, 4.6 mph

Overview

Rudder Controls
Rudder

This photo shows the floorboards in two sections so they can be removed from the sleeping compartment/cockpit that is approximately 7' (2.1 m) long (between waterproof bulkheads located where frames 1 and 3 are in the plans), with the cockpit opening of 4' (1.2 m). 3" (76 mm) high coamings are added to the fore and aft decks. The king and queen planks are Western Red Cedar with the decks mitered into the edges. Inwales are added to the cockpit sides to strengthen the topsides because frame #2 has been eliminated.


Bolger's Cartopper

In this view, the foot of the mast under the foredeck, butted up against the forward bulkhead, is locked into the maststep at the forward edge of the floorboards.


The Mik Storer style holstered rudder is controlled by a shockcord (on the port side ending in a jam cleat) and on the starboard side by a control line running forward to the inwale.

At the bottom of the rudder holster there is a horizontal plate that is at waterline level. This plate matches in size the plate on the bottom of the rudder blade. These two plates increase the efficiency of the rudder, regardless of how deep the rudder blade is immersed.


Bottom of the Rudder 'Holster'

The plate on the bottom of the holster needs to be extended to the back of the rudder blade, but still open at the back so that the blade can pivot back if grounded.


Rudder Assembly
Sailing

Downwind sailing is powered by a 14 square foot (1.3 sq. m) sail hoisted on an 8' (2.4 m) mast that is built in two 4' sections held together with a 1 & 3/4" ID (45 mm) Carbon Fiber Oar Ferrule. The two 4' sections and the sail can be rolled up and stored in the cockpit.


Cartopper with Downwind Sail

The sail is controlled by two sheets. The sheets run from the sail back to a dead eye, forward to a bollard and then to a jam cleat. The bollard idea came from a Yrvind post.



Sail Controls

To help control downwind tracking, a 2 & 3/4" (70 mm) deep full length skeg is added. The idea for this came from Clint Chase's Drake (see construction photos).


Full Length Skeg
Shelter


The 'tent' shelter is supported by the mast. The foot of the mast has a small 'lip' on the forward edge which hooks under the king plank on the forward edge of the mast slot. Headroom under the tent at the after end of the cockpit is 42" (1.1 m).

Mast as Shelter Support

The forward coaming is slightly relieved by a 1/2" (13 mm) to keep the mast from sliding side to side. Just forward of the coaming are two dead eyes to provide anchors for a tie down that holds the mast on the coaming. Note that the mast slot is closed by a plug, held in place by shock cord, while rowing (not shown here).


Hold-down for the Mast Used as Tent Support


Tent Shelter in Place

This view, looking aft, shows the bottom of the large waterproof access hatch (held with 2 black turnbuckles) in the bulkhead which provides not only flotation, but many cubic feet of storage space while cruising.


Cockpit Looking Aft to the Bulkhead  

This oar cruiser really appeals to me: Compact, pretty, and ideal for weekend cruising in waters that most other cruisers can't reach.



12 comments:

  1. I must say that your ideas with respect to 'oar cruising' are interesting, inspiring, and, like Bolger, often enough 'thinking with an open mind.'

    While I'll continue to row my beat-up 'glass boat (heretical in some on-line circles) I'll also continue to read what has become my favourite rowing related blog. LouP

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    1. Hi Lou... Thank you... On a dreary Sunday morning, I appreciate the words..l
      'Glass' boat? Who cares... it gets you out rowing and enjoying the quiet, the solitude and the satisfaction of depending only on yourself, and not petrolium nor wind.
      Tom

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  2. Yes food for thought indeed.Many innovations to inspire and stimulate.

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    1. Good morning, Andrew... glad you found some ideas to inspire.
      What sailboat is your "Pearl" (in your ID photo)? She looks like a very compact cruiser...
      Tom

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  3. I have been following your blog and find it very inspiring. A year ago I sold my rowing dinghies due to advancing arthritis. Over winter, I built a couple of paddling boats. I use the rowing machine now and again for painful reminders about rowing. I would like a camp aboard paddling boat. The best idea I've seen on your blog is Michalak's Lar's boat. I am now using his Imre's Boat and think it is very good. Any other boats I should consider? Thanks, Gerry

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    1. Good morning, Gerry...If I understand you correctly, you are looking for boat that you can sleep in, that can be paddled (no rowing) with a double paddle and I assume you can handle either on a trailer or car topping.
      Given those requirements... here are some suggestions:
      Lars Boat<, which you mentioned, would work... to make is lighter and easier to handle, use SOF (Skin On Frame) for the decking... she's 15'6" long and 30" wide and will hold a load of cruising materials and be easy to paddle with her narrow bottom and long waterline length.
      Michael Storer's Quick Canoe is very similar in dimensions to Lars Boat... easy to build.
      IMRE seems to me to be too small for overnight sleeping on board, but that 'smallness' makes her easier to handle and paddle...and she's designed to be double paddled (low sides too save the knuckle busting)
      Bolger's Minium Kayak is another possibility, but too small, I think, for overnighting.
      A more radical idea would be OarMouse... she's only 33" wide, V bottom to reduce wetted surface and keeping the chines out of the water... you'd have to sit on a low seat to paddle it... use SOF for decking... she'd be plenty big enough to sleep in and carry cruising stuff.
      Another Michalak design that would work would be Marksbark, 18' by 3'... plenty of room for cruising, but heavier to handle and paddle.
      Gerry... all of these (except IMRE) are buried in this blog in one form or another... hope this helps... Please keep us informed about your quest and/or write me at tomoarcruising@gmail.com

      Tom

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    2. Thanks Tom! This is terrific. From first reading about the various boats, I really like the Oarmouse! I look forward to many hours of charts and drawings. Your own conversions are invaluable! I also came across Byrnes' Birder II. That includes a method I've never tried. Bonus! Thanks again. I shall keep in touch. Gerry

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    3. Hi Gerry... I looked over the Birder II... nice! I think it fits your requirements (as long as the distance between the two bulkheads is greater than your height)
      She looks about 15.5 feet long and with just one person, the chines are just touching so she'll move very well with a double paddle...
      Thought of another one... Michalak's Toto, probably his most popular design... Jim, himself, has camped in it, sleeping aboard.
      Another possibility is Dave Gentry's Chuckanut... take a look at his site... I built his Wee Lassie and building SOF is fun and the boats are VERY light...
      Tom

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  4. Very nice work, going to the Eastern Atlantice messabout?

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    1. Hi Peter... Thanks! And no, I can't make the Eastern Messabout.

      Tom

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  5. Hi Tom, Have just revisited this item: Bolger's cartopper as an oar cruiser as I like visiting your blog whilst I try to find the best way forward towards 'oar cruising perfection'.Of course increasing maturity is a 'fly in the ointment' to which consideration has to be given both to the boat's design and to the considerable effort involved in building the craft ones self.Many of the innovations and ideas to be found on your blog are extremely interesting and helpful not only to building from scratch but also to improving a second hand purchase to suit ones personal circumstances .
    By the way the small cruiser 'Pearl' shown in the my id signature is a Newbridge Topaz 17 ' bilge keel cruiser GRP and wood about one ton displacement. I restored it some time ago and had a lot of fun with her. Many people liked her pretty looks!

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    1. HI Andrew... good to hear from you again.

      One ton displacement seems high to me, unless she's (really) heavily built... She certainly is a sweet looking little cruiser!

      I can definitely relate to your 'fly in the ointment' issue... I'm feeling the same way... Scares the heck out of me... How are you coping with it?

      BR... Tom

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