opinions on 14' baja blast jet boat 120hp

[david.avery]

Hey guys

A neighbor is selling a 96 Baja Blast 120hp of these with trailer for 4K:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4572701523

120HP, small, 40mph, nice handling, trailer, cool interior, etc. Seems like a good low cost way to have some high speed fun. Anyone have one of these to comment? I live close to the CT river, and have lots of easy launch spots. Have a young family, might enjoy it... what do you think?

[Teutonics]

I just picked up the Bayliner equivalent of this a couple of months ago... Mine is not in as good of condition (at least from pictures appearance), but paid 3k. Same 120hp Mercury sport jet engine, but 15 ft instead of 14 ft.

I bought it to teach my girls (oldest is 5) to ski because of the safety factor of a jet boat (no prop to worry about). I've had it out on the water about a half dozen times, and here are my observations:

Upsides
-fast top end speed
-small size makes it easy to trailer and launch/load by myself
-cheap entertainment, burns about 10 gallons of gas in an afternoon

downsides
-no low end, won't pull me on a tube without some creative driving (200 lbs, haven't tried skis yet)
-no adjustable trim
-either "on" or "off" throttle and steering is really twitchy
-really loud, my youngest (3 yrs)doesn't like it after a while
-too small to really take whole family out for the afternoon
-very little info available on the 'net (rare?)

My plan is to use it a few years until my girls outgrow it then upgrade to something bigger.

Feel free to PM me if you have any questions.

[kach22i]

Originally posted by david.avery
120HP, small, 40mph

I don't understand, is top speed 40 mph or is that a cruising speed?

My ten foot long hovercraft goes 45 mph over water (65 on ice) off of 35 hp (two stroke). If there is wind out or I just want to soak in the beauty of a shallow river I cruise at 30-35 mph (wish I could go slower not faster most of the time).

I get up to two hours use out of 6 gallons.

How is that 120 hp measured?

[VINMAN]

Most boat advertised Hp is measured at the propshaft.

[kach22i]

Originally posted by VINMAN
Most boat advertised Hp is measured at the propshaft.

So it's SHP then.

I'm guessing that it must take four times as much hp to go 40 mph as 20 mph. So to go 20 mph it would take only 30hp?

How close does that sound?

Square of the distance is sound energy, boats and speed must be more complex calculation.

[VINMAN]

With boats there are alot of variables involved, hull shape, prop pitch and diameter, x dimension , etc....
From my experience with offshore raceboats, an increase of almost 100hp would be needed to increase a boats speed 10 mph. we measure hp at the crankshaft. But then again, water conditions or a prop change can increase or decrease speed significantly.

[kach22i]

Thanks Vinman, I trust you are not exagerating to make a ponit.

Found this to help put it in perspective:

http://www.willieboats.com/sportjet.htm

TEST RESULTS

Engine Speed Fuel Fuel Range
(rpm) (mph) (gph) (mpg) (miles)
3000 25.0 5.0 5.0 210
3500** 28.0 7.0 4.0 168
4000 33.0 10.0 3.3 139
4500 38.0 12.0 3.2 134
5000 45.0 15.0 3.1 130

Old school design (kind of ugly-homebuilt) hovercraft:
http://www.hovercraft.com/15Cspecs.html

Specifications (standard model):
Specifications (standard model):
Payload

1,000 lbs. or 5 passengers
Crew

1 person
Deck Area

60" x 72"
Length

15.8 feet
Width

7.2 feet
Speed:

43 mph
Cruise

30 mph w/ full payload
Fuel Economy

1.2 - 2.9 gph
Fuel Capacity

6-12 gallons
Thrust Engine

25 hp Kohler
Lift Engine

17 hp Kohler
Skirting System

Bag Skirt

Another type of hovercraft:
http://www.aircommander.com/4.html

Lift Engine: Hirth-F23
Horse Power : 35
Electric Start: Yes
Pull Start: Yes
Max. Speed Calm Water: 48 MPH
Fuel Capacity (gal.) : 18
Fuel Consumption : 2 - 8 gph

Sale Price for AC4: $31,339.00 USD

[VINMAN]

What kind of hovercraft you have, homebuilt?

[kach22i]

I have a factory built 1989 Scat II-HP, 35 hp.

Two stroke Cuyuna, 30 inch fan, 6 feet wide x 10 foot long.

$5,000 new in 1990 (sat for a year in a showroom). I added the teeth.



Thread:
Hovercraft Experiment

Thread-2:
http://www.hoverclubofamerica.org/index.php?showtopic=412