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Old 10 August 2014, 19:52   #1
Country: USA
Town: Connecticut
Boat name: Many
Make: Many
Length: 6m +
Engine: Many
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Diesel jet RIBs

Does anyone care to comment on diesel jet RIBs.

The intended role is to serve as a tender to a twin diesel powered catamaran sailing yacht. Vessel is a 62' Leopard and the tender being considered is a Williams 445 diesel jet. The cat was sold without a tender so I have no data, just informed opinions--these boats tend to have the lightest possible 15' RIBs.

I plan to live and operate this charter boat as Owner/Captain with a cook and one deckhand.

Is this a bad idea? Or a good one?

It would be used for:
1. Primarily short hops from an anchorage to shore to pick up and drop off passengers at location close to airports.
2. As a play toy--tubing/sightseeing.
3. As a resupply vessel to ferry food, and fuel (diesel). Mothership would be moored, at times, some distance from facilities. This would allow us to hold a prime spot for lengthier periods while not in charter.
4. A fishing/dive boat to carry charter guests to more remote locations inaccessible to the mothership.
5. Filming charter activities as part of the charter package.

The single fuel and jet drive are very attractive for simplicity and safety reasons, but my primary concern is that customers have a "rave-about" fun experience that is superior to my competition. I've operated many RIBs and several larger diesel jet yachts--one with a bow thruster and the other twins, but have no experience with tender class diesel jets. I am worried it might be awkward to maneuver, smelly, or unreliable.

I want a Wow factor. Customers need to be impressed right from the start beginning with the RIB, and want to repeat the experience. Memories on the RIB platform during the term of the charter--ferry rides to shore, tubing, fishing, diving, exploring need to be better than my competition. The fun factor is 'the most important quality'. Size, speed, and comfort will impress them.

Weight may be a factor. My length will be limited to the distance between the catamaran hulls at 15', although it might be possible to go slightly larger by hoisting the bow up first. I have yet to determine how much weight the stern of the mothership can carry.

My other concerns are low speed maneuverability, reliability, and the ability to carry a heavy passenger load for at least short distances. Range with a lighter load of 2-5 people would be nice. I can see myself traveling distances up to 15 miles each way or farther to pick up supplies or for exploring.

How well would a jet work at slow speeds?

Would the diesel smell be a turn off for users?

How much throttle and noise would there be at slow speeds?

I am also considering Evenrude ETEC outboard propulsion and 4 stroke Yamaha outboard propulsion.

An advantage to the outboard would be the motor could be removed and stowed farther forward on ocean passage (2 per year). An advantage to a diesel RIB would be an extra fuel tank for the mother ship-- motoring in high pressure systems to avoid the follow on low pressure system would be the offshore passage plan. I could pull fuel from the RIB first to lighten the stern. This would extend mothership range under power.

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Old 10 August 2014, 22:52   #2
Country: UK - Wales
Town: Cardiff
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Had a trip out in one to watch the seals at worms head it was great had a play at the controls it's was awesome! It has brakes and can go full power forwards then straight in to full reverse! Hell of a party trick!

It had a yanmar inboard diesel with jet under a large housing. Could get very close to the seals very quiet so pretty good cargo area was limited but designed for seal watching so had lots of seats. There are some diesel outboards not sure on jet outboards burning derv tho.

Some details on the boat in question here: 10m so a fair but larger than you are thinking.

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Old 11 August 2014, 07:06   #3
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Hi Night_Sailor, welcome to RIBnet.

From what I have seen of the a Williams boats they will undoubtedly impress your clients as they are some of the best finished RIBs I've ever seen. I don't know if anyone here actually uses one though as they are quite a niche product and most of us can only dream of owning a boat big enough to need one as a tender!

I guess that weight is going to be the biggest factor. A DieselJet 440 is 840kg dry which seems like a lot to hang on davits and would be more suited to a large motor yacht with a garage.
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Old 11 August 2014, 13:18   #4
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Carrying a meaningful amount of fuel for the mother ship would be a challenge, not sure what economy a 62' Leopard would have but it would take a lot of trips with the tender to fill it up. It would also be limited on the conditions it could operate comfortably with paying customers on board unless they are happy to get quite wet. 15 miles in one of those with passengers would only be possible in quite benign conditions IMHO. |If you will be operating in sheltered waters none of the above will be so much of an issue but with an open boat like that weather will always be an issue.
Originally Posted by Zippy
When a boat looks that good who needs tubes!!!
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Old 12 August 2014, 12:12   #5
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i agree with cookee

it depends a bit on the area you want to operate, in sheltered waters the boat will be ok I reckon. also keep in mind that next to the spray issue in coastal conditions, especially with short steep waves, jetboats will have the tendency to loose propulsion when airborne (which can be quite annoying).

ref speed+consumption: realize it is comparing apples and eggs and much depending on the type of boat used but can share some experience : had 25-26 liters per hour with 7m rib with yanmar 230hp diesel inboard on hamilton and doing 18-20 liters per hour with a larger size petrol outboard on a 35 pct higher cruising speed .

IMHO same size with outboard will be much less weight to haul around and more room to carry your 5+ pax and supplies/fuel.
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Old 12 August 2014, 17:03   #6
Country: UK - England
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Why not get yourself a "proper" 15' RIB, and equip it with a 50hp multi fuel outboard?
Evinrude do one and Barrus to.
This type of package would be lighter and have much better sea keeping.
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Old 12 August 2014, 17:21   #7
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Jet ribs are great fun as tenders, but i'm not sure how great a diesel version would be.

I also think you have some problems with weights and moving fuel tp balance the cat.

The nicest big boat tender I have seen lately was a Novurania 430 with the new light weight Yamaha 70hp. It weighed around 400kg all up, did 40kts and could pull a mono or wakeboarder.

By contrast your suggestion weighs nearly 1000kg, thats a lot of weight to dangle off the back of a sticky boat. Even removing the fuel will make very little difference to the overall weight, and the amount of fuel it can carry will be a drop in the Ocean compared to the amount your main boat will use.

IMHO there is no need to reinvent the wheel, lots of companies make stunning tenders with convential outboard power.They are light and dont smell, a big plus point for your guests.
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Old 13 August 2014, 17:49   #8
Country: UK - Wales
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How about a standard rib with a diesel outboard or 2? Baltic Machinery¬*‚€Ę¬*Yanmar D40

Fleetwater Marine UK - Fleetwater Propulsion - JetPac Propulsion System

This looks interesting
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Old 13 August 2014, 20:53   #9
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Originally Posted by HDAV View Post
How about a standard rib with a diesel outboard or 2? Baltic Machinery¬*‚€Ę¬*Yanmar D40
only if all his guests are deaf!

sadly I don't think this ever got enough traction and went out of business...

This looks interesting Multi Fuel | Klaxon Diesel Outboards
if you were going for a multifuel you might be better sticking to one of the mainstream brands who have been working with the military (as 250kts referred to earlier).
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