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Old 03-08-2009, 11:04 PM   #1
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Hamilton Jet Drives

Anybody ever run one in a deep v mono in u.k.? Wot did it go like if you did?
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Old 04-08-2009, 09:16 AM   #2
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Only asked as me and mrs went for a wander on sunday,Bodellwydell castle boat jumble 1st,treated myself to a new vhf and chart plotter(with all of ireland on it)stainless anchor and chain and some other bits and bobs,sunday roast in a pub at Rhos on sea,LLandudno for a wander round the shops and a coffee watching the inter hotel charity waiters tray race,then a blast on the 30ft 14 seater jet boats round the bay,40knots max,fully laden,turned on a tanner and stopped dead in its own length,old iveco truck engine,280h.p.linked to a Hamilton jet drive,120 litres all day,4 trips an hour all day,very impressed.A waltzer on water,wonder what it would do with a mercruiser v8 in a p25?Ended up sitting on the prom at colwyn bay chuckin chips at the seagulls,greedy little ****ers,surprised they could even take off,spent the last hour catching the rays and watching the tractor trying to drag all the seadoos in at low tide,home at eight for the obligatory tea and strumpets,makes a change to go out in a car.
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Old 04-08-2009, 09:20 AM   #3
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Many, many years ago I used to look after a jet boat for someone. I was I think a 17' Hamilton (boat & pump) and had a 3.0 V6 Ford fitted.

I didn't see the point in it myself, but in the right situation I can see they'd be fun / useful.
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Old 04-08-2009, 09:38 AM   #4
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Check out Hamiltons web site,based in new zealand,very in formative,no props to wreck,no drag,dead easy to manouvre,any body on here done it yet?
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Old 04-08-2009, 09:51 AM   #5
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Well their website is gonna big em up aint it.

They may not have appendage drag in the normal sense, but they're pretty ineficient, so for a given power, they're slower than prop drive.

They certainly have huge manouverability in close quarters (once mastered) but normal steering is rubbish unless the power is on, there's no true neutral, so they walk about (which I found quite annoying when on my own, mooring up etc).

To me, it seemed ok all the time you drive aggressively (needs the squirty thing to be working hard), but the slowness and other downsides put me right off as a replacement for traditional propulsion. For use in shallows etc, or if being operated with people in the water, it clearly has advantages.

It's hardly a new idea, and hasn't exactly taken over the world.
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Old 04-08-2009, 09:57 AM   #6
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Has anybody done it yet tho?
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Old 04-08-2009, 10:00 AM   #7
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Quote:
Originally Posted by dowdy View Post
Has anybody done it yet tho?
Done what?

The Hamilton 17 was deepish V Mono and I used it on the river, and the coast (UK, out of Hayling Island) (testing) see above posts for opinion. (I thought it was crap in that application)

Tearing up the shallows and canyons in NZ would be a whole different thing, but we don't really do that here.
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Old 04-08-2009, 10:08 AM   #8
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http://boatmad.com/forum/showthread....ight=class+jet
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Old 04-08-2009, 10:12 AM   #9
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We have a 120hp diesel waterjet rib in a 6 metre hull (including the tubes) and it's great fun, does 34mph, good for wakeboarding and safe, but I wouldn't put one in a performance boat unless I wanted to do the stopping in its own length type tricks all day long or go up shallow rivers as Jon said - no point.
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Old 04-08-2009, 12:39 PM   #10
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Mate has had a couple of SeaDoos. Good fun & quite quick (55mph) but that's from 240BHP on an 18' boat. It looked to me like the top half of a 225 Merc outboard sitting on a jet-pump.

What would you think you'd be getting top end on an 18' outboard boat with 225BHP? 60+mph I'd 've thought. Not that good in the shallow stuff either 'cause they keep sucking up debris & jamming. Used a lot of fuel as well.

Only real advantages I could see was the ability to turn tightly at speed & no prop to cut peoples feet off.
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Old 04-08-2009, 12:50 PM   #11
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Had a Glastron CV19 a few years back with a 455cu in Buick and Berkley jet sounded fantastic but not very efficient. Good rooster though
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Old 04-08-2009, 12:57 PM   #12
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All i can do is ask the question,got some off the answers i was. looking for,think i will stick with 525 and bravo 111x option,should be up and runnin for my birthday,cant wait.
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Old 04-08-2009, 01:07 PM   #13
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Makes me laugh the way "they" say jet drives are more efficient.

Jets have less appendage drag than conventional shaft drive, but compared to a surfacing drive (whether outdrive, outboard or shaft), they are still naff. The smaller the jet is the more innefficient it is too (area of the nozzle is small compared to the surface area of the jet unit).

Trying to remember the rule of thumb for jets - seem to remember upto about 40 knots being a rule of thumb, beyond that efficiency drops right off. Can't remember for sure though.
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Old 04-08-2009, 01:17 PM   #14
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Max on a single seems to be 50kts then they go twins,99%of the applications seem to be commercial,not many performance boats about with it by the look of it,enjoyed my ride anyway,not so sure about mrs,she didnt eat her chips after.
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Old 04-08-2009, 01:23 PM   #15
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Quote:
Originally Posted by Jon Fuller View Post
Done what?

The Hamilton 17 was deepish V Mono and I used it on the river, and the coast (UK, out of Hayling Island) (testing) see above posts for opinion. (I thought it was crap in that application)

Tearing up the shallows and canyons in NZ would be a whole different thing, but we don't really do that here.
Roofer and Hutchy and a few others do it all the time at Riverside
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Old 04-08-2009, 08:05 PM   #16
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jets

We do alot of work on the boats that patrol the gunnery ranges at Lulworth and Kent they have twin 350hp Yanmar on Hamilton jets they are very heavy lots of gear on them made of alloy and they top out at 32kts.
The Shockwave boat that does trips from Bournemouth pier has twin 440hp Yanmars on RR jet units and they can make it do allmost anything but for all that horse power will only run at 45kts but it was not designed for top speed.They had to have jets because of swimmers and the manouvrability. The drives are rebuilt every year at great expence due to the sand at the pier.
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Old 04-08-2009, 09:58 PM   #17
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Quote:
Originally Posted by TECKNO 40 View Post
We do alot of work on the boats that patrol the gunnery ranges at Lulworth and Kent they have twin 350hp Yanmar on Hamilton jets they are very heavy lots of gear on them made of alloy and they top out at 32kts.
The Shockwave boat that does trips from Bournemouth pier has twin 440hp Yanmars on RR jet units and they can make it do allmost anything but for all that horse power will only run at 45kts but it was not designed for top speed.They had to have jets because of swimmers and the manouvrability. The drives are rebuilt every year at great expence due to the sand at the pier.
so working on this and other posts as ime seeing it the jets are very power parasitic compared to props then
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Old 08-08-2009, 10:48 PM   #18
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I used to have a 16' Dowty with a Hamilton Jet and a whopper of an engine but rarely got it above 32kts with one on board. As has been mentioned before, they are great if you need to worry about shallow draught but to be honest I wouldn't.
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Old 09-08-2009, 08:16 AM   #19
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Trend Curves

Summat for Capt Chaos to mull over when deciding the finer points of waterjet selection.

These are comparsion transmission curves drawn up for a variety of craft.

The vert axis is wt in lbs/bhp.Red are shaft drives,blue are surface drives,green are waterjets,black are outdrives.Waterjets were mainly used where the owner had a large yacht and need to go into shallow bays and stock surface drives were not available in such large sizes,but they were efficient for Patrol Boats and in one case were used by the Spanish Customs to chase after ex-Shead racers on the Morocco run.On the other extreme they were used on Roger Penske`s 50m Gas Turbine 40kt Motor Yacht.Then there was `The Jet` in 1974, a sister to `Unowot` with castoldis,before surface drives made a name in 1980.One can see from the curves that the dots can be scattered a bit,so it`s not all as predictable as you would like.
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Old 09-08-2009, 08:45 AM   #20
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My step dad used to drive a jet rib with iveco turbo diesel. It was an awsome boat and with increased revs and perfect bucket control (and mastering the turning wrong way while going backward thing) him and the boat could get in and out any spot (particular shallow water) far better than any single enginened conventional drive boat!!! BUT it only did about 30knots. If it was really rough on big seas they could "bucket" down rollers to control speed and stop a stuff, in the solent with its short chop it tended to loose prime on the pump and as a result surge in speed between fast and slow!!!

Great for shallow water, and for jet skis and a bit of fun, good in really big seas and commercial situations but like said before, seem to be slower!!

Unless ya gonna go for a U.S unlimited jet thing
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