# What the Heck Is It?! (semi trailer design)

**URL:** <https://boards.straightdope.com/t/what-the-heck-is-it-semi-trailer-design/963803>\
**Category:** Factual Questions\
**Created:** [May 2, 2022, 12:12pm UTC](https://boards.straightdope.com/t/what-the-heck-is-it-semi-trailer-design/963803 "2022-05-02T12:12:07Z")\
**Posts on this page:** 4\
**Page:** 2

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**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\
**Post date:** [May 2, 2022, 4:11pm UTC](https://boards.straightdope.com/t/what-the-heck-is-it-semi-trailer-design/963803/21 "2022-05-02T16:11:30Z")

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> [@Grrr](#):
>
> It seems like it’s hauling a chemical to me. But why triangles instead of a cylinder?

The triangles allow the fluid to funnel to the pipe at the bottom, which allows better capability to drain the tanks fully.

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**Author:** ![DorkVader](https://avatars.discourse-cdn.com/v4/letter/d/73ab20/32.png) [@DorkVader](https://boards.straightdope.com/u/DorkVader)\
**Post date:** [May 3, 2022, 3:12am UTC](https://boards.straightdope.com/t/what-the-heck-is-it-semi-trailer-design/963803/22 "2022-05-03T03:12:43Z")

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Thanks, fingers and phone were conspiring to not cooperate (heh!) with me at the time.

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**Author:** ![Bookkeeper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bookkeeper/32/281_2.png) [@Bookkeeper](https://boards.straightdope.com/u/Bookkeeper)\
**Post date:** [May 4, 2022, 5:41am UTC](https://boards.straightdope.com/t/what-the-heck-is-it-semi-trailer-design/963803/23 "2022-05-04T05:41:27Z")

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> [@Jasmine](#):
>
> That’s pretty much it except that there are no extra bars going from the base to the top frame, just that ladder thingy bolted right in the middle. Also, they don’t have the front part of the trailer that almost touches the ground.

I thing the “front part” is just sheet metal air dams along the side to provide streamlining for better fuel mileage. These ones appear to be an integral part of the trailer rather than being bolted on as an addition.

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**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\
**Post date:** [May 4, 2022, 11:21am UTC](https://boards.straightdope.com/t/what-the-heck-is-it-semi-trailer-design/963803/24 "2022-05-04T11:21:27Z")

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Thanks!

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