Optimax fuel economy

Daniel · 16 April 2004, 00:21

Having just returned from a substantial voyage i though some people would like a report on the Opti's fuel and oil consumption.

Tuesday was dead, dead calm all the way from the Solent to Eastbourne, we made 35-42knts all the way and fuel consumption was the highest i have ever seen it, average 0.8nm / li. We used almost exactly 100li, which is about 25% more than i expecred. Most of the time we were sitting at 5000 rpm. We also used an alarming amount of oil, about 3-4litres.

Previously (in 40 hours) we have used a total of 8 litres of oil.

Wednesday was very thick fog, so we sat at a sensiable 20knts (150-200ft visability). Eastbourne-Ramsgate saw fuel consumption rise to an average of 1.2nm/li, using a total of 60litres, and little over a litre or 1.5li of oil. This was acheived with the Dover-Ramsgate leg at a constant 39-41 knts.

What have i learnt? Optimax economy goes out of the window above about 4k - 4500 rpm. Don't go RIBing when it's flat!!!

I'm afraid i have no pic's of this trip because i forgot the CF card for the camera but i'm extremely happy with the long-distance cruising ability of top-banana after completing the 200nm trip back from Poole. Interestingly i also met another top-banana in Eastbourne - not nearly as banana shaped though

Hope the figures help some people looking at engine choices! Given 50 hours of running now i would still choose an optimax.

swginn · 16 April 2004, 00:33

Had the same experience last wkend with my friends tornado/ 135 optimax. Sea was like glass. Ended up chasing ferries to get some waves. Spent most of the wkend at around 4000-4500. Very expensive wkend, Opti oil is a bit more expensive over here too!!

When I've got my own I'll just have to have a bit more discipline. Can't wait though, Optis are great engines. Those first couple of weeks are gonna hurt the wallet. It'll be worth it though!!

RLS · 16 April 2004, 09:15

Hi Daniel,
What is the accelleration like on top banana with the 150 opti? Also what is the dead rise? What is your flat out speed too? I am just wondering as my new 6.4 is arriving hopefully a week on sunday with a 200 opti.
Look forward to hearing.
Thanks

Daniel · 16 April 2004, 09:19

Deadrise - unknown, will attempt to find out.

Top speed so far is 46 knts @ 5200 RPM. Can't pull top RPM but i like it that way - think economy!

Over the last few days we only managed 43knts, but were 3 up + about 200li fuel + overnight luggage for all.

Yesterday i managed in excess of 40knts with 5 up and around 150li fuel.

The acceleration is great, don't know how to describe or measure it but straight on the plane. Your boat will go like stink with a 200opti, bet you can't wait!

RLS · 16 April 2004, 09:26

Thanks a lot, always great to get an insight how the baby is going to run.
Your right I can't wait especially with all this nice weather we've been having!

Rogue Wave · 16 April 2004, 12:21

My point about Opti's and fuel economy has always been that you get a lot of economy at a considerably cheaper cost than a four stroke. If me memory serves me well the 150 redlines at 6k ( and the limiter cuts in shortly after that) so at 5k you are using more than 82% of useable power and all engines start to suck it up at that speed.

I think that's a very reasonable fuel consumption for what is a high speed passage.

I very much hope to have my Opti back on the water soon, and will look forward to putting in as much fuel as the little baby wants.

I know one guy with a 7.5 and a large Yammie four stroke that sucks about 70 litres at 47 knots.

Also having had the pleasure of getting to know you and Tappy better lately you could always rename the boat to Top Bandana if there was too many Bananas in the bunch

Daniel · 16 April 2004, 12:56

Stu call me about your gearbox AND GET A NEW MOBILE

thorper · 16 April 2004, 13:29

Hi

Our HPDI uses a load more fuel once you get the revs over 4000. Running at 4000rpm we get 40mph.

We went round the island on easter sunday and burned 75ish litres without much effort at all. Not sure about the oil usage - the HPDI doesnt seem to use that much, but it uses a load more when you're hammering the engine.

As you say Daniel, its far too tempting to floor it when its calm. Running for a long time at 5000rpm does sound like quite a lot of work for the engine, so I'm not surprised you used a load of petrol.

Ricky.

Manos · 16 April 2004, 13:54

Daniel tyhis engine is dead economic to run. Impressive figures there!
I want to see what you would have said if you had a VMax

TIPS · 16 April 2004, 16:34

Thought I recognized the name Top Bannana, saw you in RMYC in Poole last weekend.

Mark

Daniel · 16 April 2004, 16:39

Argh, i recognise the boat profile - that was Friday evening. We were looking for somewhere that wanted less than £45 per night. Ended up going back round the coast to Christchurch, albeit VERY VERY shallow!

ozz · 16 April 2004, 16:52

Hi Daniel,
I too was concerned over the weekend at the oil consumption on my 225 opti. 1st run of the year (nancy warm weather boater) and we burn't about 300 litres of fuel and probably 7 litres of oil. Most of it was at high speeds as it was so flat but your figures have made me feel better!
Anybody know of cheap place to get the stuff? I ended up paying £27 for 4 litres from a fuel berth as I was not expecting to run out....

Graeme

Daniel · 16 April 2004, 16:58

Wavehumper (Stu Hopkins) or whatever he calls him self now has a load he will sell you at a good price. pm or e-mail him.

I pay about £15 for 4litres i think, which is a very special price!

Rogue Wave · 16 April 2004, 17:01

Quote:

Originally Posted by ozz

Hi Daniel,
I too was concerned over the weekend at the oil consumption on my 225 opti. 1st run of the year (nancy warm weather boater) and we burn't about 300 litres of fuel and probably 7 litres of oil. Most of it was at high speeds as it was so flat but your figures have made me feel better!
Anybody know of cheap place to get the stuff? I ended up paying £27 for 4 litres from a fuel berth as I was not expecting to run out....

Graeme

that's a ratio of 43 to 1 which seems extr high, i'd have a chat with your mechanic. I bought a 45 gallon drum for 800 quid inclusive so if you are down our way I can ley you have 20 or 40 litres at cost. but you shouldn'y pay any more than 22,50 at a chandlers. Fuel pontoons are however one of the last places in Britain where certain forms of piracy is still legal

Daniel I have a new mobile it's on charge

swginn · 16 April 2004, 17:04

In Ireland Optimax oil is €41.50 (£27.72 in Sterling). Anybody know if I can order it online? I intend to bring it back in bulk when I'm collecting my new rib, but it would be handy to be able to order the stuff as well once I run out!!

Daniel · 16 April 2004, 17:06

The problem would be it's heavy and might not work out that cheap once delivered. You can but 10li cans but they don't seams any cheaper per litre than the 4li ones.

swginn · 16 April 2004, 17:17

Guess I'll be loading up so when I'm over, otherwise the 10hr over-oiling period will hurt the wallet, at our prices anyway. How much should I expect to pay for a 4li can?

I know it'll be worth it though. I'm jealous listening to ye talking about your Optis!!

TIPS · 16 April 2004, 18:57

Quote:

Originally Posted by Daniel

Argh, i recognise the boat profile - that was Friday evening. We were looking for somewhere that wanted less than £45 per night. Ended up going back round the coast to Christchurch, albeit VERY VERY shallow!

We were just on the left as you came in. Did you try Dolphin Quay? they had space that night and over the weekend, we paid around £70 for the week for a berthing there.

Mark

Aging Youth · 16 April 2004, 19:48

Hi Stuart,

Once it is charged please let have your new number. left several messages but no reply. See you soon mate.

Kevin

Cookee · 17 April 2004, 09:26

Quote:

Originally Posted by Rogue Wave

that's a ratio of 43 to 1 which seems extr high, i'd have a chat with your mechanic. I bought a 45 gallon drum for 800 quid inclusive so if you are down our way I can ley you have 20 or 40 litres at cost. but you shouldn'y pay any more than 22,50 at a chandlers. Fuel pontoons are however one of the last places in Britain where certain forms of piracy is still legal

Daniel I have a new mobile it's on charge

If you ever get down our way I'll have what you can spare mate - otherwise I may be coming up your way soon ........