There is no Perfect Boat �� Buyer guide jetcraft.ru Boat Materials

The last thing is � there is no free lunch. Most boats are a compromise. Boats that work well in shallow water may not work so well in rough water. Props are good for some things and not others. Wide beam boats are nice, but take more power. Accessories are

great, but add weight and cost. Pretty boats with lots of carpet and upholstery are nice at

the lake with docks, but not so good when landing on muddy or rocky shores. Paint is

nice unless you are going out camping, hunting rough whitewater trips. Head height

(camper) tops the full length of the boat sound great in theory, but are you really going to

be running out in the rain or sleep on the boat? These are decisions and tradeoffs that you,

not the salesperson should feel comfortable with and be able to make informed decisions

about.

The same basic hull and power plant can cost $40,000 or $70,000 depending upon

accessories. The performance will be the same (well actually the boat with less options

will probably perform better because it is lighter) - it is up to you what you want to

spend. Questions you need to answer include:

� Will you be comfortable?

� Will you look as good?

� Will you be as dry?

� Do you like the exhaust rumble of the 350 or do you like the lighter weight of the

2 stroke.

� Will you be able to use the boat in all weather conditions?

That depends on you, your budget and what you want to do. We actually like to sell

fewer accessories, as it makes for a less complicated boat that is more user friendly.

Take a test ride

We strongly advise a test ride, either in a prospective boat, on a friend�s boat or via a

dealer. You can almost always test a Marathon boat. To quote Hotboat again:

� . . . if you are in a buying mode . . . you not only deserve . . . a pre-purchase ride

or drive, you owe it to yourself. If a builder cannot arrange for that to happen

either through a factory demo ride or by . . . hooking up with an owner, there�s

something wrong � if not with the boat, with the service. With due respect to the

builders who have proven their product, my advice is to walk at this point.�

Test rides are great, but what do you look for?

Acceleration out of the hole

Pay attention to acceleration out of the hole or �holeshot�(-� in drag racing, it refers to a heads-up race where the slower car beats the faster car by leaving the line (legally) first�.). Lots of builders give

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large (beam) but at the expense of a narrow bottom that gives you slow acceleration. For

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example, quite often you will find boats with an 83-85� beam, that only have a 5�6�

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bottom, as compared to a larger 6� bottom. This translates into slower acceleration and

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less load carrying capacity. If you just look at beam, you will get fooled. You can

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visually see this when you look down the boat from the bow or transom (fore and aft,

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bow and stern). If you see the sides leaning way out, like a �V�, that is likely what is

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going on.

Why do manufacturers do that? One reason is that many buyers just buy based on the

specs. So, in the boating reviews etc, you will see beam as a measurement. There is

nothing wrong with that, however for a boat, the more important (and generally ignored

measurement) is bottom width. The bottom/hull is what interacts with the water. That is

the platform which makes up the boat. It is pretty much impossible to make up for a

bottom that is wrong for you.

Although not strictly correct, there is a good correlation between acceleration out of the

hole and potential weight carrying ability. Generally speaking, faster acceleration means

larger weight carrying ability (between two boats of equal engine size).

However, as discussed later, bottom width is not the only factor which affects

acceleration. �The Hook� and bottom shape also have an effect. So, do not make hole shot

the only indicator you use � keep watching as there is more going on as the boat

accelerates.

Boats: What to Look For. �� .

Introduction.

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Welded Boats in General:

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Our Bias

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Shop for a Manufacturer First

Look in the used boat ads

Judging the Production Staff

Manufacturer Reputation

Buying a Welded Boat for the First Time

Know the Boat you want

There is no Perfect Boat

Take a test ride.

Acceleration out of the hole

Bottom Width and Engine Size and Type. �� ....

Turning ability.

Stability at Speed: Porpoising versus bow down �� .

The Hook.

Spray Line?.

Boat Materials: Aluminum versus Fiberglass . ��

Cost differences between glass and aluminum . �� .

Types of Aluminum. �� .

Material Thickness

A Word about Welding

Suck marks, caterpillar tracks

Folded, �Origami� Construction

Hull Design

Delta Keel.

Deadrise (Vee)

Planing Hull Bottom Types ��

Constant deadrise V (including modified V hulls)

Flat bottom hulls (8 degrees deadrise or less)

Bow Entry Types. ��

Shallow Entry

Sharp Entry

Radius Bottom �� .

Lift Forces Explained.

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

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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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Spiridonov S. E.

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JETCRAFT. ��. �� . ��. ��. �� . �� . (Boats: What to Look For . Buyer guide)