A boatstretcher is any wickstretcher that stretches a boat. The first one to be discovered, boatstretcher 1, was found by Hartmut Holzwart in June 1993. Note that in any boatstretcher, the point of the boat can be removed to get a tubstretcher, although long tubs are called barges.
A 39-glider synthesis for a crab-based tubstretcher was constructed on February 12, 2017, by Tanner Jacobi and Adam P. Goucher. Goldtiger997 reduced this to 32 gliders on October 27, 2019. By hitting the tubstretcher with two gliders in the right position, it is possible to destroy it and leave behind an arbitrarily long boat, proving that an N-bit still life for any odd N can be constructed with no more than 34 gliders. Likewise, BlinkerSpawn discovered that a single glider can destroy the tubstretcher while also turning the boat into an arbitrarily long barge, showing that a still life with any even-numbered population can be constructed with no more than 33 gliders. On March 22, 2017, it was shown by Goldtiger997 and BlinkerSpawn that, even without using the reverse caber tosser, an arbitrarily large oscillator can be constructed with 45 and 46 gliders respectively for odd and even N, by tying a quadpole to the still life.
- Adam P. Goucher (February 12, 2017). Re: How about a crab synthesis? (discussion thread) at the ConwayLife.com forums
- Goldtiger997 (October 27, 2019). Re: How about a crab synthesis? (discussion thread) at the ConwayLife.com forums
- BlinkerSpawn (February 12, 2017). Re: How about a crab synthesis? (discussion thread) at the ConwayLife.com forums
- Goldtiger997 (March 22, 2017). Re: How about a crab synthesis? (discussion thread) at the ConwayLife.com forums