What is the problem of going on a boat (and by proxy doing elective surgery) less than three days beforehand?

  • I would perfer another answer other then the rambans Motion sickness answer if there is another one Commented Jan 25, 2011 at 13:31
  • Where do you get the idea that there is a problem?
    – Isaac Moses
    Commented Jan 25, 2011 at 15:23
  • Issac why the intrest Commented Jan 25, 2011 at 23:41
  • Isaac -- see below, sorry for the confusion.
    – Shalom
    Commented Jan 26, 2011 at 17:22
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    @SimchasTorah, When I ask for you to provide the premise of your question, it's not necessarily that I doubt that there is one. It's just that the question is much more valuable in many ways if it's clear where it's coming from. For example, if you're aware of this halacha because you learned it in a Mishna, cite the Mishna in your question, and that gives everyone a head start in answering it, since they can see precisely what the Mishna actually says and will know to start by looking at the commentaries on the Mishna, etc.
    – Isaac Moses
    Commented Jan 26, 2011 at 18:55

1 Answer 1


The Talmud, Shabbos 19a, states:

ת"ר אין מפליגין בספינה פחות מג' ימים קודם לשבת במה דברים אמורים לדבר הרשות אבל לדבר מצוה שפיר דמי

One may not depart by boat less than three days before the Sabbath ... although if for a mitzva purpose, it is allowed.

There are I believe nine different explanations in the Rishonim about why this is (and hence, in what situations it applies). As you've mentioned, one explanation is that you shouldn't be seasick on Shabbos, so give yourself a few days to gain your sea legs!

Another answer is that being on a boat (and by extension, elective surgery) is putting yourself into a situation where you may need to violate Shabbos due to life-and-death circumstances. Now certainly once you're in such a situation, you are absolutely obligated to save a life; but it's less than ideal to choose to put yourself in such a situation to begin with. According to this explanation of the Mishna, however, you only need to think about "what situation am I putting myself in" if you're within three days of Shabbos. Any earlier, and it's not your responsibility. (Similarly, if the trip is needed for a mitzva purpose, there is an argument to allow it even within the 3 days, as that wins out over the halachic strong preference of don't-put-yourself-in-a-situation-where-you-may-be-obligated-to-violate-Shabbos.

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    And depending on which approach you take, you may have different halachos in various contemporary applications so that boat and surgery my have different halachos.
    – YDK
    Commented Jan 25, 2011 at 17:39
  • You wouldnt happen to have the Mareh Makom or be able to provide the other nine Commented Jan 25, 2011 at 23:42
  • Mishna Berura (hebrewbooks.org/pdfpager.aspx?req=14171&st=&pgnum=25) mentions 5: 1) You're putting yourself in a dangerous situation where you may have to do melacha; 2) The gentile captain is doing melacha for you; 3) You are traveling outside the Techum; 4) Seasickness will mess with your oneg Shabbos; 5) Sailing is within the decree of swimming- you may build a raft. (See intro for reason of 3 days- which include Shabbos itself acc. to Gra)
    – YDK
    Commented Jan 26, 2011 at 16:53
  • An interesting application would be flying from, say, LA to Tokyo on a Friday afternoon- 1) A dangerous situation? Questionable. 2) Captain doing melacha for you? No, most passengers will be gentile. 3) Traveling out of the techum? You were above 10 tefachim before shabbos. 4) Airsickness? Certainly not similar to seasickness 5) Maybe you'll build a raft- not likely and anyway, your seat cusion can be used as a floating device.
    – YDK
    Commented Jan 26, 2011 at 17:04

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