efficient 10m displacement powercat (build thread)

We bought a drone to capture our adventures, here's a sneak peak with more to come, especially capturing the boat whilst in motion is next on the list...

 

Much better view than the old 'crows nest'

 

That is awesome. A Cat may have to be my next build

 

Beautiful location!

 

These drones are a big innovation.

 

This is truly an amazing thread of planning, ingenuity, dedication and some serious hard work. Probably this forum is the only place where a collective group of people might appreciate the hours that went into this boat. I have restored a number of glass boats but this effort, in your yard after work/weekends is literally superhuman.

Groper, you are amazing. Here's to you and your boat! Congratulations (just read the whole thread)

 

This is a wonderful video we have produced which highlights everything we have done with "catch 22" so far.
We have crossed the coral sea twice and travelled over 3000Nm in her thus far. Fuel burn figures in a heavily laden condition seem to be holding around 1.6L per Nm average travel speed of 16kts- we sometimes go faster and sometimes slower but we averaged 1.6L per NM for the last 1000nM in a wide range of conditions.

Can't say enough good things about these suzuki outboard motors. They have been absolutely flawless.

We are very proud of this video and we hope you share it around to inspire more people to get out there and just do it!!

https://vimeo.com/190509671/description

 

Like your video, though I'd like to see some footage in a lively sea state. The fuel consumption is about where you expected it to be ? It might have been a bit better with smaller motors, you could probably have got away with as low as 2x70, or do you think that would be underpowered ?

 

Fantastic!

 

Wow! Sure, great video and something to be proud of. But WOW is really for your achievements: design (yes in the early days there were doubters...) and build (just downright exceptional). You ought to be very, very proud of what you did. 'Catch 22' is really beautiful. You and your buddy be sure to take your partners on more trips so that their patience during the next build can be asked for! They seem to have more pairs bikinis than I have pairs of shoes, but that's fine!

Even if you could have used smaller motors I suspect you would not have seen much better fuel efficiency. They would have used smaller props and more rpm to get the same thrust.

It was a pretty gutsy trip you guys did! Kudos! One question, how was the customs/immigration aspect of leaving Oz, entering PNG and returning to Oz managed? I am contemplating a long cruise next year, 6 months or so instead of the mere 3 months I just completed, and could be tempted to 'follow your footsteps'. But really curious as to how the border crossing aspect works in practice.

 

Incredible
Beautiful
You have me seriously torn between go fast boats and cruisers here man.
Is there plans or kits for something like this that look as good?

 

One thing to try would be running only on one motor at a time.

 

Speeding, no need to be torn mate, you can have go fast and cruising ! The water skiing footage didn't make the cut this time, but we have been wake boarding and tubing behind catch 22 aswell
The wake from the cat is little hard to make use of tho!

90hp susuki motors would have been perfect , I think 70hp would be too small. The 90hp can swing the same props as we are currently running. We crusing between 3200rpm for 13kts and 4200rpm for 20 kts. This is a little low in the range for the Japanese engines and the 90hp motors would allow the same speeds in the 3500 - 4500rpm range which is closer to where the engines are designed to run @ 4000-4500rpm. This would save another 80kg off the stern also... but I coukd never find a second hand pair of 90s... so the 115s happened...

Everywhere we go people are surprised to see us there, they always ask what our range is and what speed we do and how much fuel do we hold... most boaties and commercial fisherman are left scratching their heads as to how we can go the distances we do between available fuel stops in these remote areas with 600litre fuel tankage...

Customs is PNG is a joke... dont be surprised if they ask for a bribe... they didn't search us or anything just wanted money. Notify them of your arrival via email and get your visa before you leave from the PNG consulate here in Oz. In australia you need to fill out a B333 form with border force and notify your departure. When coming back you need to give minimum 4 days notice and again use the b333 form via email. They board you on arrival and you also have to pay quarantine clearnace fees which are typically around 300 400 bux but it depends on the boat and officer of the day as to how much time they spend...

 

Lessons learned

Groper, hats off for your execution of a great project-very inspiring for all the rest of us with more ideas than ambition.
Now that she's a real vessel with some experience under way, do you have thoughts about what you might do differently were you to start the project again? Your comments on the engines (above) are along the lines of what I'm thinking of. Also a different design philosophy, construction process, etc.
Any input you have would be appreciated.

 

The main thing I would change is keeping the round bilge further Aft before flattening the bottom. It pounds in a heavy headsea which is disconcerting and probably limits our speed into which we could otherwise maintain in heavy conditions without feeling like we will break something.. I'm looking at modifying the hull bottom with an add on v section underneath in the front 1/3 forefoot in the near future to see if I can improve it.

Build method worked out well. Wish I had a full length table to infuse on but I only had limited space available in my garage. I'd probably invest in a proper hoop house shed next time so I had better conditions and more space to build in. I'd also explore the option of infusing a stack of panels at once. I'd probably also make use of premade CNC routed panels from duflex in the interior bulkheads etc as I'm not so concerned with using balsa core inside where it's not really susceptible to water ingress. I'd stick with foam core for any exterior panel.

Apart from that, I only wish she was bigger and had a nice set of sails so we could live on her indefinitely and travel the world in comfort