Alloy jet

[speedboats]

Just finnishing one of our little boats for a local client. 14'6", 175hp Mercury Sportjet. Does a bit of hunting in more remote areas hence the cage over the engine cover. He'll take it away to fit and finnish then I should see it back in a couple of months.



Blanks fitted in the mount holes for the cage


The cage

[JETTYWOLF]

Ya ever wonder why Honda, know for thier 4 stroke engines has not come out with something exactly like the Merc sportjet?

I have. Is it because a "jet" needs to be connected to a "chainsaw, weed eater" type motor to get the rev's??
Don't believe so, because many big bad jetboats have Chevy 454 iron's under the hood.

Things that make ya say, Hmmm.

[spoiled one]

The four stroke outboards don't provide the low end grunt that the two strokes do. This is essential in a jet that is required to get the boat out of the hole and plane out in a boat length. There are plenty of big block V-8s in the big jet boats, but they don't run the skinny water that a sport jet will.

[welder]

Honda has up to a 105HP jet motor at this time> http://marine.honda.com/Products/modeldetail/BF105 < if the motor is matched to the boat correctly I think either motor will get the boat up on step PDQ.
Other things we look at when building these river beaters is...
1) Cost
2) Weight
3) Dealer support
4) See #3 again
5) Horse Power needed ( Honda doesn't make a bigger motor for that app.)

To each there own, run what ya brung.

[JETTYWOLF]

That's not what I'm talking about Welder.
I'm talking about something like the merc sportjet.

Sorry....example off 2coolfishing, and reinforced plastic resin boat.

Once ya get away from two stroke 1200 hr. blow ups and buying TCW-111, ya just never want to go back.

(1. if you use the boat alot.
(2. See #1, again.)

C'mon

[speedboats]

The four stroke outboards don't provide the low end grunt that the two strokes do. This is essential in a jet that is required to get the boat out of the hole and plane out in a boat length. There are plenty of big block V-8s in the big jet boats, but they don't run the skinny water that a sport jet will.

Not guite as lw down as you'd expect as most pumps won't place much significant load on the motor 'till 2000rpm. The good part about jets is that the load to the motor is exactly the same regardless of boat load, and the best part is the manouverability you get at low speed.

All those jetsprint boats have large V8 motors and are up on plane within their own length. Most of my boats use a V8 and waterjet combo and are used up shallow rivers, some even V6, although there is a move towards smaller 11' boats using jetski powertrain in them.

Toyota 1UZFE (4.0L V8, 280hp)


Chevrolet LS364/440 (Carb'ed LS2, 440hp)

[Napa Mike]

Hey Speed Boats:

Thanks for sharing your pictures. When I use my imagination to picture what a speedy jet boat should look like, the imagine is just like your boats. They really look great!

Mike

[speedboats]

Here's some vid of the boat. It was the new owners 2nd time out, so a more sedate river was called for. Unfortunately the Go-Pro we had onboard was flat so the footage is from a handycam and smart-phone, which we go bored with holding so missed alot of the better bits.

You'll have to excuse the guy with the hand gesture, it would seem he didn't wish to appear on camera...

http://www.youtube.com/embed/yGxVhjdanfE

Coming down the river...

http://www.youtube.com/embed/9c3JFWSG4gg

[welder]

She came out reel nice and sounds good.

I like the Bloody Decks Salute.

[pjay9]

Do you always have the river to yourself...saw a red boat tied up and maybe a float in the bushes further on? You were going down river where would you end up? What river? Thta is pretty cool...good video and sounds nice as Les said. What was the speed? THX for sharing.

[speedboats]

No we don't always get the river to ourselves, however there isn't a huge amount of traffic either. The Red / Orange boat belongs to the local tour operator there, and as we had a couple of cruise ships in harbour they were booked to take 200pax up the river the following day. The river can be quite boring as it's a non-technical drive however is scenic as it meanders its way to the river mouth and into the Pacific Ocean.

Here is the google earth address of the tour operator (Kaituna River Jet)
37°49'51.18" S 176°23'41.55" E

You will see a smaller river that flows into the Kaituna just a little down stream to the operators jetty, we did manage a trip up there (no camara as we got bored of holding it), touched some rocks twice. It was a little more difficult to boat (still comparatively easy to other rivers) with a few shallow sections and gorges that would have been about 17' wide (we were only just able to turn the boat around in one), Water was suprisingly clear being 3' deep in places but able to clearly see the pebbles on the river bottom (as strange as it may seem that is not real common around here as NZ intensively farms and we get alot of run-off of nitrates and phosphates into our rivers, that is when farmers aren't pumping all the water for irrigation). It is a trout spawning stream and we could well see a few trout 'duck for cover' as we boated past.

The boat only achieves 52mph, which is fine for what it is with the 175 Sportjet. Pump is a little small when you have 5 big-block guys like me on board, but was intended for the owner to get to the upper reaches of rivers to areas inaccessable by road to go hunting (mostly deer and pig) and then bring them all out, hence the removable 'game cage' over the engine cover. However he has decided that the boat is a little small for what he wants so is selling this one to get our bigger 4.8m model with an 8 1/4" pump and possibly Chev LS2 motor (that'll lift 5 big-block guys while towing a skiier!).