In Brief

Tom Thumb 24 Sail Plan [image courtesy of Bruce Roberts Yacht Design] The Tom Thumb 24, designed by Grahame Shannon sits at the extreme for steel boat designs. At 24 feet of length this little boat by conventional standards would be too heavy to work, but Shannon shed weight with clever use of steel as a skin over a frameless interior, stiffened by only interior furnishings much like the interior lining in modern fiberglass designs. And so the wee Tom Thumb 24 makes an appearance as the smallest of steel go anywhere cruisers.

She’s a sturdy little boat and capable at sea. In spite of her short hull, heavy displacement and wide beam, the Tom Thumb 24 has a reputation for surprising speed. She can easily surpass her theoretical maximum hull speed of 6.2 knots, can point reasonably well, and thanks to her weight her motion remains comfortable.

Interior space has been described as “roomy”, owners under 6 feet in height will have standing headroom.

Many have been built worldwide, quite economically, by amateur boatbuilders. As with the nature of home build projects you can expect interesting variations between boats. The design has enjoyed unexpected success and has inspired a range of siblings including the Tom Thumb 26, 28, 305 and 330. They can be built in multi-chine steel or aluminium. Plans and kits are available from Bruce Roberts Yacht Design.

Comments from the Designer

I designed the Tom Thumb 24 in about 1983 as a bit of a joke. I had designed other steel boats and used to get a lot of people asking “why are there no small steel boat plans?”. I used to give the standard answers (too heavy, can’t make the plating thin enough without distortion, etc.). Then I had the idea that if we designed her like a GRP boat with a monocoque hull, frameless, using interior plywood furniture as stiffening, that the weight would be within reason. After a few calculations, I saw that this would work.

Tom Thumb 24 Layout [image courtesy of Bruce Roberts Yacht Design]

I thought “Let’s give them what they want” and drew up a list of requirements, including full keel, bowsprit, standing headroom, and inboard diesel, with a “shippy” look.

I drew up the plans over about 8 weeks with assistance from John Woods, who also had worked for Bruce Roberts when I did. Then I placed an advert in Cruising World offering plans for $99 with a small line drawing. Response was amazing and within a year we had sold 300+ sets of plans. Then I sold the rights to Bruce Roberts, and he has sold many hundreds more, I don’t know how many exactly. He also designed the similar Tom Thumb 26 based on the 24.

I designed other frameless steel boats, notably the Amazon 29 and the Opal 28, neither of which came anywhere near the 24 in popularity. In fact until I designed the Walker Bay 8 dinghy, the Tom Thumb 24 outnumbered all of my other designs put together in terms of boats built.

Not only did the plans sell better than expected, the boats turned out well and we received many reports of her good sailing characteristics.”


LOA: 7.26m (23′ 10″)
LWL: 6.71m (22′ 0″)
Beam: 2.92m (9′ 6″)
Draft: 1.22m (4′ 0″)
Displacement: 3,590 kg (7,900 lbs.)
Ballast: 1,360kg (3,000 lbs.)
Sail Area, Main: 201 sq. ft.
Sail Area, Genoa: 196 sq. ft.
Mast Height: 34′ 6″ above deck

Headroom: 6′ 0″

Designer: Grahame Shannon
Construction: Steel ( 10mm keel, 5mm hull, 3mm decking)

Similar Boats

Roberts Tom Thumb 26
Roberts Tom Thumb 28
Yarmouth 23

Links, References and Further Reading

» The Tom Thumb 24 on the official Bruce Roberts website
» Furled Sails audio webcast, an interview with designer Grahame Shannon [Tom Thumb mentioned 30:00-31:50mins].
» Rainbow Chaser, owner blog.


Thanks goes to Tony Fountain (co-writing and research), and also designer Grahame Shannon (designer comments used under permission). Additional owner feedback from Bruno Caroit. Use of line drawings kindly granted by Bruce Roberts.


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6 thoughts on “Roberts Tom Thumb 24”

  1. Bruno Caroit says:

    Hi Joseph,
    sorry for the delay and yes with pleasure…
    My email:

  2. Caroit Bruno says:

    Tiguidou is a Tom Thumb 24′ that I rerigged as a junk schooner four years ago, and after sailing 2,500 miles in the St.Lawrence Gulf, I can only say that I love this sturdy little boat… Quite fast, roomy, comfortable and beautiful..!

    She is roomy inside and I can walk all along under the roof (5′-11”).

    In spite of her short hull, heavy displacement and wide beam, she is quite fast. She easily surpass her theoretical maximum hull speed of 6.2 Kn. She points reasonably well, as a full keel sailboat with fine entry can tack through 90 degrees of apparent wind in flat water, 100 when it becomes rough, but thanks to her weight she remains quite comfortable.

    However I know that western junk rigged boats have a rather bad reputation against the wind, and it is because almost all of them had quite low aspect ratio and flat sails in the past. But now, a combination of curved pannels on higher aspect ratio sails, as on Tiguidou, give very similar results on the wind than an average marconi rig on a similar hull

    -Bruno Caroit

    1. Tony says:

      I read your comment with interest and as I have just finished reading a wonderful book an an Englishmen that sailed his junk rigged 20 footer to the Arctic Circle and back, I am getting interested in the rig concept, Any information would be appreciated.


    2. Bruno Caroit says:

      Hi Tony,
      there is a ”junk rig yahoo group” which is a good source of information. Have a look at Arne Kverneland’s technical file:” Junk rig for beginners”.
      The great book ”Practical Junk Rig” written by M. Hasler and M. Mc. Leod covers about everything on the subject: general descriptions, the pros and the cons of these types of rig, very precise suggestions and beautiful drawings to help you design and build one for your boat, how to sail her then…It has been my bible for a couple of years…
      Annie Hill’s very good ”Voyaging on a small income” is a pleasure to read and could easily convince someone to become a ”junkie”as she says…
      Please tell me who is this man who sailed to the Artic

    3. seerauber says:

      G’day Bruno,

      The man was Roger Taylor and his 20′ yacht is called “MingMing” – details on I have purchased his book and found it a most inspirational read. I have Annie Hills book and I have taken many tips fro it, not the least of which is learning to cook in a pressure cooker!


    4. Joseph Alfieri says:


      I am interested in more details on your Tom Thumb 24 junk rig. Can we talk via e-mail?


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