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JETCRAFT. Водомёт. Водомётный движитель. Теория. Лодка. На что обратить внимание. Руководство пользователя. (Boats: What to Look For . Buyer guide) |
Marathon Marine - web. Cтатья очень доходчиво рассказывает НА ЧТО ОБРАТИТЬ ВНИМАНИЕ при покупке лодки или водомётного катера.
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NEW. Росомаха (img) русский конкурент Harbercraf / Jetcraft
Byuer Guide Руководство покупателя
Фотографии с выставки "MIBS 2009" Закон и катер. Постановка на учёт катера со стационарным двигателем. дюймы в сантиметры
Форумы на тему... с переводом.
Harbercraft 1875 J-Max White Water (img)
2075 White Water (img)
1875 J-Max XS (img)
2175 XS Фотографии с выставки "Охота и рыбалка - 2008"
Marathon Marine and Northwest Jet Boats (link)
PHANTOM Jet Boats (link)
RiverPro®. (link)
North Silver PRO 675Jet lnk
Росомаха (img)
Tom 525. Томь 525.
Коллекция ссылок на тему: водомёты для судов (Links). Курс доллара
Друзъя
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Lateral Stability During Planing Turns Поперечная устойчивость во время плоского поворота. Because of its large convex surface the Radius Bottom also generates tremendous lift -
much like the flat bottom hull but without any of its nasty habits. To hold the hull
throughout a turn lateral stability is provided by strakes each of which are specifically
sized and placed on the bottom. These strakes contribute to the lateral traction of the hull
giving our boat its extreme tight turning performance. More lift translates directly to
more payload capacity, less fuel consumption and a faster more nimble hull. Unlike the V
hull the Radius Bottom also creates substantial positive lift while in a turning maneuver.
This results in a solid stable cornering boat with the attitude of the hull remaining flatter
throughout the turn. In addition the combination of the Radius Bottom, high rising chines
and aggressive bow entry produces a solid dry riding boat that lifts over chop yet slices
through waves. It is truly the best of both worlds.
The ride, lift strength and stability of the hull is such that we have equipped a number of
standard 12 degree deadrise Radius Bottom hull’s with outboard offshore brackets using
225 HP outboards. These boats are operating in the severe conditions of the offshore and
inland waterways of Alaska with superb performance reported by the operators.
Bottom Shape and Jet Intake
Planing hulls have many different shapes or lines. In a water jet powered craft, design
errors that would not show themselves with other drive types will become critical. Flow
to the jet drive unit is extremely important. One of the most significant advantages of the
Radius Bottom is its ability to interface with jet drives. The Radius Bottom transitions
perfectly into the pump intake area of the jet drive. This delivers solid water to the eye of
the impeller resulting in a dramatic increase on pump efficiency and boat performance.
Simply jamming a jet drive into the rear of a V hull will not work. The flow into the
pump intake must be a clean, non-aerated flow at all time - in all conditions. Since the V
hull is by far cheaper to build than the Radius Bottom hull most builders “transition” a V
keel to accommodate the needs of the jet drive. The easiest way to do this on a V hull is
to incorporate a Delta pad (flat triangle) into the bottom. Most manufacturers do this the
easiest, least costly way by forming the Delta pad from the stem cut out (where the bow
begins to rise) all the way back to the stern. This is usually done with a press brake. Many
times it is done by splicing and welding the Delta (triangle) into the bottom. Either way
they are weakening the bottom in the process.
The Delta pad, because it is flat, will generate lift when the hull is planing but it will also
exhibit the same bad characteristics of the flat bottom. It will also have the tendency to
cavitate (ingest air) in rougher conditions. The Radius transition can best be described as
a spoon shape. Whether the boat is on plane or taking off from a standing start the jet
drive loads beautifully. Look under a few boats and see the difference for yourself.
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Boats: What to Look For. НА ЧТО ОБРАТИТЬ ВНИМАНИЕ при покупке лодки. Введение Сварные лодки в общем Наши предпочтения
Buying a Welded Boat for the First Time
Bottom Width and Engine Size and Type.
Stability at Speed: Porpoising versus bow down Дельфинирование.
Boat Materials: Aluminum versus Fiberglass .
Cost differences between glass and aluminum . Сравнение стоимости стекловолокна и алюминия. Types of Aluminum. Типы алюминия.
Material Thickness
A Word about Welding
Suck marks, caterpillar tracks
Folded, ‘Origami’ Construction
Deadrise (Vee)
Planing Hull Bottom Types Корпус с дном плоского типа
Constant deadrise V (including modified V hulls)
Flat bottom hulls (8 degrees deadrise or less)
Bow Entry Types. Тип носа катера
Radius Bottom Круглое дно.
Lateral Stability During Planing Turns
Bottom Shape and Jet Intake
Planing Ability
Reverse Chines
Bottom Width: Flair is not everything
No Trim.
Hull Construction Standards
Shallow Water Operation
No Exposed Drive
Safety
Thrust line and Center of Gravity In line
Propeller Torque is Different than Impeller Torque
Propulsion Resistance.
Power Plants Силовая установка. Derived from Impeller Curves.
RPM Curve Derivation
Conclusion
Hull Resistance. Boat attitude..
Jet Drives
How jets work .
Impeller
Cut.
Cut, Speed and Load
Wear ring.
Nozzle
Stator.
Hard Anodized.
Cavitation .
Intake
Seals
Mixed flow
Axial flow.
Outboard jet:
Inboard jets:
So, what is the best jet?
Corrosion.....
UHMW...
Jet Diagnosis...
Rattle at Idle (V8 boats)
Speed too low for a Given RPM.
Poor acceleration or ‘holeshot’, combined with high top end
Definitions.
Porpoising .
Chine walk: 9
Ram effect .
Static thrust:
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Водомётный движитель. ТЕОРИЯ.
Адрес для переписки:
Spiridonov S. E.
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JETCRAFT. Водомёт. Водомётный движитель. Теория. Лодка. На что обратить внимание. Руководство пользователя. (Boats: What to Look For . Buyer guide) |