Open deck
Double drop
حوض ثابت بين سطحين مرتفعين، للبضائع العالية التي لا تحتاج إلى الصعود ذاتياً.
شكلها
المواصفات
| القياس | Double drop |
|---|---|
| طول السطح | 29′ |
| ارتفاع السطح | 1′ 10″ |
| العرض القانوني | 8′ 6″ |
| أقصى ارتفاع قانوني للحمولة | 11′ 6″ |
| السعة المعتادة | 45,000 lb |
هذه أرقام اسمية لهذا النوع من المعدات. الحاويات الفعلية تختلف حسب المصنّع والخط الملاحي وسنة الصنع، والوزن الفارغ مطبوع على باب الوحدة التي تصلك. أرسل لنا رقم الحاوية ونتحقق من الوحدة الفعلية.
What a double drop is
A double drop is an open deck trailer that drops twice: once behind the tractor and once again in front of the axles, leaving a low well in the middle with a raised deck at either end. The well floor sits about 1 ft 10 in off the road, runs around 29 ft long, and is 8 ft 6 in wide like any legal trailer. A typical unit carries something like 45,000 lb of freight.
The gooseneck at the front is fixed, so cargo comes into the well from above or from the side rather than being driven on. That single fact separates it from the removable gooseneck trailers, and it is why a double drop suits crated and lifted freight while wheeled and tracked machines usually go elsewhere. These are typical figures for the type rather than one trailer's.
When a double drop is the right trailer
When the freight is tall and not especially heavy. Around 11 ft 6 in of legal cargo height is available in the well against roughly 10 ft on a step deck and 8 ft 6 in on a flatbed, so tanks, vessels, machinery with a high housing, and anything that would otherwise need a height permit tend to end up here. Being able to move legally is usually cheaper than moving permitted.
It is the wrong trailer when the load is heavy, because a lowboy is built for weight and a double drop is not. It is also the wrong trailer when the piece is long, because the well is short and everything outside it rides high. And if the cargo is under 10 ft, a step deck is easier to load and easier to place, with far more of them on the road.
What people get wrong: the well is the trailer
People book a double drop against the trailer's overall length and then discover that the usable floor is the 29 ft well. A piece that is 34 ft long and 11 ft tall does not fit a standard well, and putting the ends on the raised decks defeats the point, since the raised decks sit at flatbed height and the load is over height again. Measure the piece and compare it to the well, not to the trailer.
The height sum works the same way as on any open deck: Florida's limit is 13 ft 6 in measured from the road, the well floor takes its share, and the freight gets what is left. Anything above that is a permitted, routed move rather than a normal dispatch. Weight has a similar trap in reverse: the 45,000 lb figure is what the trailer typically carries, and where the piece sits in the well decides how that weight lands on the axles.
What to send to get it booked
Length, width, height and weight of the piece, measured as it will sit, including the cradle or skid it rides on. Then say how it will be lifted, because a fixed gooseneck trailer needs the cargo to come in from above or from the side, and lifting points or fork pockets decide what happens at both ends.
Add the sites. A low trailer has less ground clearance than an ordinary one, so a steep driveway apron, a curb cut or a rough yard is worth mentioning before a driver is committed. If the piece is over 11 ft 6 in tall, over 8 ft 6 in wide or longer than the well, say so at the start: that is where permits, escorts and a different trailer come into the conversation, and all three are planned rather than improvised.
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What is the well on a double drop trailer?
It is the low section in the middle, between the raised front deck over the kingpin and the raised rear deck over the axles. The trailer drops twice, which is where the name comes from, and the floor of that middle section sits about 1 ft 10 in off the road. Tall freight rides in the well and nowhere else, so the well is the part of the trailer that has to fit the cargo.
How tall can freight be in a double drop well?
Around 11 ft 6 in as a working figure against Florida's 13 ft 6 in travel limit, because the well floor starts so low. That is roughly 18 in more than a step deck allows and three feet more than a flatbed. It is a lot of height, and it is bought with length: the well is only about 29 ft, so a tall piece has to be short enough to sit inside it.
How long is the well on a double drop?
About 29 ft on a standard trailer, which is the number that decides most jobs. The raised decks at each end can carry freight too, but they sit high and give you nothing on height, so a load that needs the clearance is working with 29 ft of floor and not the trailer's overall length. Where the piece is longer than that, the conversation moves to an extendable or a stretched deck.
What is the difference between a double drop and a lowboy?
Mainly weight and how the cargo gets on. A double drop has a fixed gooseneck, so the freight is lifted into the well, and a typical trailer carries something like 45,000 lb. A lowboy sits lower still and is built heavy, commonly around 80,000 lb, and the removable gooseneck versions let a machine drive on. Tall but ordinary weight goes on the double drop, tall and heavy goes on the lowboy.
Can freight overhang the ends of a double drop well?
It can sit on the raised decks and it can overhang the rear, but both cost you the thing you came for. Anything resting on a raised deck is back to flatbed height, and a rear overhang has to be flagged, lit and measured into the combination's overall length. If the piece is long and tall at the same time, that is usually an extendable or a stretch deck rather than a standard well.
ما الذي يُنقل على Double drop؟
حوض ثابت بين سطحين مرتفعين، للبضائع العالية التي لا تحتاج إلى الصعود ذاتياً.
هل تتولون التصاريح؟
نعم. كل ما يتجاوز العرض أو الارتفاع أو الوزن القانوني يُستخرج له تصريح ويُدرس مساره قبل أن يتحرك، مع المرافقة حيث يقتضيها الطريق.
هل تتعاملون مع الـ reefer؟
نعم، مع genset حتى تبقى الحاوية تعمل بين المحطة والباب. حاوية الـ reefer تحمل أقل بوضوح من حاوية جافة بنفس المقاس الخارجي، لأن العزل وجهة المكينة تأخذان مساحة حقيقية.
وماذا عن البضاعة التي لا تدخل في حاوية أصلاً؟
flat rack وopen top لما يخرج عن الأبعاد، أو مسطحة مكشوفة: flatbed، وstep deck، وlowboy، وRGN، وdouble drop. قِس البضاعة قبل الحجز، لأن كل ما يخرج عن الأبعاد يغيّر مسألة التصاريح.
كيف أحصل على سعر؟
أرسل الخط، والمعدة، ومقاس الحاوية، والميناء، ونرد عليك برقم. التسعير والتشغيل على مدار 24 ساعة على quotes@dariaslogistics.com.
ما الذي يشمله عرض سعر الـ drayage فعلاً؟
النقلة نفسها، إضافة إلى الرسوم الإضافية التي يفاجأ بها الناس لاحقاً: الشاسيه، والـ pre-pull، والـ per diem، والـ demurrage، والـ detention، والتخزين. نفضّل تسميتها من البداية على إضافتها إلى فاتورة.