Searching for fuel efficient powerboat

Our boat burn at 7knts 0,82lt per nm but at 8knts it's 1,46 lt per nm
But it could be better because in this case we have the "brake" of the second proeler not in use .
Our boat could be lighter (just one engine ,less wood inside, less tools less less )
Before built our 'longcours62' we hesitate to built a trimaran like Ilan but with litle more space inside it is the way for power efficiency .

 

Chuck, as you are finding, a custom boat is the way to do it. Have Bieker send the bid package to Dennis Choate at Dencho. You may well be pleasantly surprised.

 

5700 pounds at $60/lb is about $342k.......a nice used boat and a lot of fuel is still far less.....

 

At the other end of the spectrum might be the Tenessee by Bolger....

 

Tad, you are a designer, so I'll bet you have seen far more bid packages than I have. However, those I have seen are $15 to $30 per pound for a displacement powerboat. So obviously, we are not comparing apples to apples.

Parenthetically: I absolutely love the boats you design, Tad!

Now, I have seen sailing catamarans at about that price, but those are VERY highly loaded structures, with VERY high end complex and sophisticated systems and sails. Specifically, $5M for 60,000 lbs is approaching $100 per pound.

The $15 to $30 range reflects the amount of systems included, from pure camping to everything I would want for trans oceanic excursions. But I've actually spent an awful lot of time doing that, so I know I still don't want much aboard no matter where I'm going.

For a bare hull and deck, one-off molded foam/stitched multiaxial e-glass/vinylester to race boat level of fairness and painted in and out to super high quality finish in imron, I get quotes of about $10 per pound here in southern california: $45000 for 4500 lbs, 50 feet by 8.5 feet with full standing headroom (1800 square feet of deck/hull/bulkhead/floors), with not a straight line, or developable surface, to be seen. And not a piece of wood in the construction (the mold of course has lots of wood). I will not name the builder who gave me this specific quote on this forum, but I got similar numbers worldwide 3 years ago before the depression started. I would be very surprised if the prices are not lower now!

Now, to be sure, ALL systems need to be added to this $10/lb price. But each of us has our own requirements of systems, from my wife who essentially prefers camping, to me who also likes water, to some people who think a boat should be a house + mobile city utility companies. Most people seem to be in the latter group. But that group usually uses their boats as floating condominiums in a marina, rather than actually cruising around and taking advantage of being fuel efficient.

This is a fuel efficient thread. That means long, thin, slow, and light. Lose any one of those, and fuel efficiency is a dream instead of a reality. Light is easily achieved if one keeps things simple, and simple can mean cheap. Cheaper than the per-boat contribution for the advertising budget of Nordhaven (to paraphrase another comment you made, Tad).

 

My memory might be failing me, but I think Bieker told me that 40 was expected to cost something like $150K in foam&glass.

 

Agreed.

Funny thing, $5/gallon diesel fuel costs changes everything when it comes to power boating!!!

Also be aware of the extensive work done by Phil Bolger & Friends in the last decade on fuel efficient boats, a number of designs: The recreational, Topaz. The cruiser, Sitka Explorer. And a series of professional fishing boats, part of their Advanced Fisherman series, Robin Jean, etc.. Military, the SACPAS-3.

All of them achieve fuel efficiency by keeping things light, and taking advantage of low resistance possible with long narrow 'flat' hulls. Like Tennessee, but with a more well developed curvy forefoot/cutwater.

 

The original poster mentioned a passage in the open Pacific along the Baja coast, despite her attributes I don't think Tennessee or any of her sisters belong out there.

The plywood box may be an alternative if you are not paying for labour and are willing to forgo return on investment.

I would like new custom boats to cost less than they do, but I've given up being optimistic about it. A high quality product from a builder who will still be there next week is not inexpensive.....The product of low bids is unfinished boats where the money ran out......

We can compare apples and oranges all day and something might be gleaned from it. Currently a low quality production boat (not ready for sea) can be had for $17-25/lb, and a high performance cruising cat runs over $90/lb (not ready for sea). A Swift Trawler from Beneteau is about $36/lb not ready for sea.

This year I have a quote for a plywood (essentially kit boat) outboard boat (without motor, trailer, or any extras including electronics) at $25/lb and I'm concerned it's not enough. I have a bare bones quote for a foam cored e-glass and epoxy shell built in Southern California at about $24/lb with no tooling, design, or engineering, no systems/wiring/plumbing/tanks/power/etc (not ready for sea). I have another quote from the same part of the world for the same 40' boat bare bones complete with single engine/no generator/no AC/and painted surfaces inside at $32/lb with no tooling/no design/no engineering.(not ready for sea)

A high quality build from a very reputable East Coast USA builder will cost $50-60/lb ready for sea.......and there are lot's of ways to get a boat that cost less........

 

I went on G...

for have a look of the Tennessee (sorry i am French and , i don't know her !)
I am not a designer but when I take a look of the bottom it seems to be very "flat" for going with current or tide against wind (I am not very clear)
We had one boat with quite flat bottom (83 ' aloy) but when you are at sea with 'current against wind' you became little anxious about the structure and the welding , when you eard the bottom hit the waves and the plating make 'bloum, bloum bloum ' from the bow to the transom ...
I take a look also from the same designer at 70' fischerie ...also very flat !
The advantage of flat bottom , may be it is very nice wake ;;;by nice weather !

 

I like the look of Biekers boat.

Have a look at Nigel Irens designs. Also fuel efficient. http://www.nigelirens.com/ldl/

One thing is certain, top class naval architects love to design efficient boats. You have a wide choice.

 

Flanking rudders?--Kinda?

 

Have a look to this yard: www.greenlinehybrid.com, that might be the one you are looking for!

 

Thanks to all for the suggestions. Don't have the money for a custom built boat. If I did I would have already knocked on Tad's door. So I am limited to existing boats. And there lies the problem. Powerboat design has not changed in eons since it took a turn for the worst in the early 1900's and is driven by marketing that you need a condo on the water and heaven help you if it should roll even a fraction of a degree at the dock or underway. People don't "buy" big ticket items like boats. They have to be "sold". The higher the price, the more profit. So from the marketing stand point more is better. That has left us with expensive wallowing tubs that can't get out of their own way and never pass a fuel dock without stopping.
Take your typical double cabin powerboat, whether it be a trawler or motor yacht. it doesn't really matter much because they are all pretty much the same. Roughly 65% to 70% of the living space is devoted to sleeping and shitting with the galley, dining table and lower helm being crammed into the remaining 30%. I don't know about you but I would rather have more living space than sleeping space. And flybridges. IMHO what an expensive waste of dual systems and added complexity. When it gets even mildly rough out there you can't use them and at night you can't see out the plastic windows. But everybody according to the marketing folks needs one. So to keep the weights as low as possible, the lower helm is crammed so low that you can't see over the bow and you have to crawl on your belly like a snake to check out the engines while under way. Yuck.
Common sense suggests that a power boat should get better fuel economy than a sailboat because you don't have to push the deep keel through the water or the rig through the air. But that doesn't seem to be the case. From my experience it seems like the powerboat burns twice the fuel of the sailboat at similar speeds.
I am talking about boats in the 35 to 40 size range. My humble opinions may not apply to bigger boats but I believe they do. Sorry for the rant. I can get carried away at times. Better stop before I offend somebody and if I have, I apologize.
Chuck

 

Well the above 4-5 posts cover enough ground to write several books on.... these are really important and central to the "Fuel Efficient Powerboat" issue so I'll try to address them quickly......

First I'll mention use.....Chuck's original post mentioned an open ocean passage, thus I think the discussion should be limited to ocean going fuel efficient powerboats. Maybe that's just me, fair enough, but I don't think the issues that apply to fuel efficient river cruisers are the same. Thus the Greenline boats with their Cat B certification are not relevant. And I don't think Mr. Irens Rangeboat types are intended as ocean cruisers, they don't carry much at all in the way of liveaboard cruising gear or enough fuel for a long passage.

Yes, any good designer can create a lightweight boat which can be very efficient in it's use of power, but there is a downside......The downside is payload (the stuff you can bring) and motion. Yannick and Jacqueline (Longcourse) have written me regarding motion and it's something I've been concerned with since the beginning of the Passagemaker Lite concept. The Dashew's deal with quick motion though the use of seatbelt/shoulder harnesses....that's an option that could be quite workable for some. But if I was undertaking say a nonstop voyage to Tahiti I would rather have an acceptable level of comfort and run a bit slower to gain efficiency. Finding the sweet-spot tradeoff between efficiency and comfort is a tough one and work remains to be done. The US Navy has done some motion sickness testing, because of course people who are seasick are no good to them. I can see incorporating those findings into lighter passagemaker designs. I have no idea how much Mr. Bieker has considered this for his boat, will the paravaves slow her down (or pull themselves apart), and is the low water ballast a good thing? I don't know........

Personally I will continue with offshore boats that are not ultralight and have some hull depth below DWL(as Longcourse).....I am working on a 40' right now that will displace 5700 pounds and run 12mph with a 25HP Volvo....but it's no offshore boat........

 

I know you guys like to see a statement of requirements and I have drafted one. It is attached. It is kinda like a wish list and may or may not be very realistic. I realize that what I would like to find might be just an unrealistic pipe dream.