Category Archives: Building

Wild Thing – You make my heart sing

What an exciting moment. Last Saturday it was finally time to pull our Arrow 1200 out of the shed, step the mast and put her into the water. There are so many things to do at the moment to fit her out properly for our first sailing adventure in August, I will post details later. Here are some snapshots:

A few tasks to do

A few tasks to do

20160709_13444620160708_172935

Get her moving

Get her moving

crane lifting ....

crane lifting ….

... into the water

… into the water

20160709_170602

Bad luck!

I had a bit of bad luck in the last couple of months. An infected bursitis needed surgical treatment and I am still having problems with my right hand. However, the building went on and actually we are not to far away from the finish line. So here´s an update.

shutterstock_114803062_1_

The painting job is finally done. The exterior is spraypainted with glossy white Awlgrip and it looks awesome. The interior is all matt white. The hardest part was getting the surfaces all even flat. You need to at least squeegee the panels twice or seal them with a light filler before sanding and painting.

Anyway, we got it all done and we are happy with the result! The galley is almost finished, with an induction field as cooker. See how that works. The Fridge is 230 V as well.

Galley

Galley

This is the generator, suppying 4 kw continuous 230 V electrical power. It is situated under the forward bunk in the starboard hull.

Whisperpower Genverter

Whisperpower Genverter

The windows (Perspex) are glued with Sikaflex.

Perspex windows

Perspex windows

This is the hatch of the forward locker and it´s huge!

forward locker

forward locker

We just started with the installation of the daggerboard cases. It was a day´s work to cut out the hull and make them fit properly.

Cutting out the hull for the daggerboard cases

Cutting out the hull for the daggerboard cases

The case is in place

The case is in place

That is how the cases break through the hull.

20160528_162334

Daggerboard case

20160528_163349

daggerboard case

The rest is business as usual – trimming the cases, decoring and backfilling the edges and finally taping the seams.

Next thing to do is the forestay fitting and the installation of the rudders. If everything works out well we´ll be in the water in 6 or 7 weeks 🙂   –   and next time I tell you what the little guy at the top has to do with all of it.

 

Hull is ready painted

Hello,

recently I did not find the time to update the blog despite the enormous progress we made. The hull is ready painted now . Stephan did a great job spray-painting all surfaces with AWL Grip 2 Component PUR Topcoat. The result is fantastic! Perfect glossy finish on most parts and antislip on the side-, foredeck, cabin top and steps. The hulls are all covered with film until everything finished but you can already imagine the perfect look.

Stephan in action

Stephan in action

Cockpit

Cockpit

cabin top with antislip

cabin top with antislip

prodder

prodder

prodder in place

prodder in place

prodder in place

prodder in place, antislip still to come

bridgedeck reinforcement, openings for sheaves to lead halyards etc. coming from the mast back to the cockpit

bridgedeck reinforcement, openings for sheaves to lead halyards etc. coming from the mast back to the cockpit

 

Next the interior kit will be installed, faired and painted. The motors will get in place next week so we can start with the electrics in about a month. The mast is ordered to be delivered in April and we hope to be in the water by May/June 🙂

More details on that soon on a hopefully more regular basis.

Cheers, Chris

Rudderbox

Short update on the rudderboxes. Enough space for the hydraulic pump and the rudder arm. The hydraulic hoses will be led to the front. On the side there is an inspection hatch to get access to the mechanics. The rudder shaft will get an additional bearing at the top with an option to mount an emergency tiller.

20151101_142624

Rudder Box

 

 

 

 

 

 

 

Inspection hatch

Inspection hatch

 

Kick up rudder cases

Hi all,

the Arrow 1200 is designed to have kick up rudders combined with tiller steering. However, we prefer to have wheel steering. In that case the catamaran is supposed to have fixed rudders what makes beaching almost impossible. So we thought about it and came to the idea of extended boxes which are able to hold the rudder stock with arm and a hydraulic cylinder … see the result below!

099

Rudder case

100


098

Rudder case

The case fits perfectly to the hull to take the forces of the rudder. It will be hinged with a SS bolt and held down with some break away device which we still have to think about 😉

That way the rudder comes up in case of collision and can be pulled up for beaching. Very happy with that!

 

 

Hull almost finished!

Hi all!

Sorry for not updating this blog more regularly. It is more time consuming than I thought and we have a lot of other things going on besides our building project. Julia is expecting again :-), due date is mid of September. And I am moving with my primary business ( also September :-() which is pretty stressful at the time.

Arrow1200

 

Anyway. there are some new photos uploaded to the gallery, so have a look. It is incredible to see the real dimensions of the cat now. From time to time I thought the 1360 would have been better but now I am definitely convinced – this is the right boat! We changed our mind regarding the tiller steering. Though I like the idea to be linked to the boat in a direct way I could not see where to sit safely as a helmsman with good sight and in reach of the sheets. So we decided to close the left window of the main bulkhead and install a wheel at that place. See the gallery for more explanations.

The next steps will be installing the remaining interior (galley, salon seating), the daggerboard cases, the electric drives and the rudders. Exciting!!!!

One more thing 😉 …. We get a lot of requests of people wanting to visit us. We perfectly understand your desire but for us it is hard to make all the arrangements, especially in the next couple of months. What we might do is selecting a weekend lets say end of October and do the sightseeing in a more compact way. Anyone who is interested, please let me know.

All the best and happy summer

Chris

Forward section

Here are two photos of the forward section.

forward section

 

The space where Roman is working is going to be the diesel tank. It can hold apx. 200 liter and will be laminated directly into the structure. The opposite side will take the water tank, it will hold about 400 liter. To prevent sloshing we need to install 2 or 3 baffels with openings at the bottom.

forward section

The frame shows the size of the hatch. It is fairly large but it makes all four compartments accessible with only one hatch. Stefan used to install these on his own designs and they work very well. The hinges are going to be on the side, so you open it from the middle.  A gasket makes it watertight. With the anchor, chain and ropes and stuff the compartments still need a drain.

cabin top

We´re not far from installing the cabin top :-))

The electric system on our Arrow 1200

There seems to be a lot of interest in our plans to power our catamaran with an electric propulsion system. And of course there are a lot of critics with proven points. If Lagoon had to replace all their hybrid systems in their charter fleet because of never ending problems why should we do better. Lagoon, probably the biggest catamaran shipyard, if they can´t do who else? Well, that was back in 2006, I don´t know the system of the Lagoon hybrids but I know that diesel-electric propulsion works. What is different to 2006? I think the key is the advance in battery technology, namely the Litium Iron Batteries. And of course the improvement in efficiency of all components, Generator, Inverter, Motor, shaft and prop makes the whole system work better than 9 years ago. So far in theory. We made our decision, for a practical review you´ll have to wait 😉

First of all, what are our needs. With twin diesels I would have decided for 2 X 15-20 hp, e.g. the Sole mini 17 or any other 2 cylinder diesel engine (Volvo, Nanni, Lombardini, Yanmar etc.) But what does that mean for electric motors. Why can we choose them smaller in terms of power and how small can they be? Basically, we are able to turn a prop of same size with a less powerful electric motor because of immediate and evenly distributed torque in the whole range of rpm. Diesel motors supply torque very unevenly, especially at low rpms there is a lack of it. That makes it hard to match the prop in terms of diameter and pitch perfectly to the motor. To compensate that yacht diesels are usually a number to big for the prop (and the yacht). That makes them speed up fast but the load at higher rpms is actually to low. In addition there is loss due to friction of a saildrive or a gearbox. Because of the evenly distributed torque it is easier to match a prop to an electric motor. Greenstar uses a slow rotating disk motor without the need for a downshift. The motor axis is connected straight to the shaft. A low friction bearing is used for the shaft. All in all the system should be a lot more efficient than a diesel Motor. Is the chosen power enough? For now I have to rely on the calculations Greenstar did for our boat. The Greenstar 20D System nominally has only one third of the desired diesel power but if you look at the facts mentioned above it should be enough. It drives two 14×8 Flexofold props. Both motors weigh 28 kg (without shaft and props).

Greenstar 20D

Greenstar 20D

 

So we got the motors, what electrical power do we need? The Motors run on 24 V DC which is nice, because I don´t have to change the voltage for the boats DC grid. At full throttle each motor draws about 150 Amps, makes a maximum of 300 Amps which need to be delivered at least for a short period of time. Half throttle, which is supposed to be cruising speed (flat water, no wind, 6 knots, the Arrow with low resistance hulls maybe a little faster) draws about 50 Amps each Motor. We want to be autonomous, so we need a source that delivers the apx. 100 Amps for cruising speed continuously, even when the battery is getting low. At first sight the Whisperpower M-GV 4 Piccolo marine system we chose seems complicated but actually it is pretty smart.

First of all there is the Motor/Generator. A 306 ccm one cylinder 5.8 hp diesel motor is turning a permanent magnet alternator at 2800 – 3600 rpm. The Motor/Alternator is fully capsulated (quiet 65 dBA at 1 m distance), fuel consumption is 0.8 – 1.2 l / hour, weight is 69 kg, it has electric start (need for an additional 12 V 55 Ah lead battery, 18 kg) and remote control. It has a unique exhaust system where fumes and cooling water are separated with the outlets for fumes above and for the cooling water below the waterline to reduce exhaust noises. All in all it should be a very quiet system. The alternator produces electricity with 94 % efficiency (using the torque of the motor ideally) but in voltage and frequency not suitable for our needs (up to 400 V at 500 Hz).

Whisperpower Piccolo Genverter

Whisperpower M-GV4 Piccolo with PMG module

To change that the WP PMG module (7 kg) is connected next in line to get pure sine wave 230 V / 20.5 Amp AC (3.5 kw continuous/4.0 kw max/8.0 kw for 5 sec. max power 95 % efficiency). It also has a 12 V/7 Amp output to recharge the starter battery.

Next in line is the WPC 24/3500-90 sinewave inverter/charger (28 kg). The numbers say it charges at 24 V/90 Amp max and inverts from 24 VDC to 230 VAC with 3.5 kw max. The efficiency is 94 %. You can not tell where is in or out. On the one side you  can connect a) the Generators 230 VAC and b) 230 VAC shore power, on the other side you connect the 24 V battery bank. The basic idea is that the WPC delivers the power where it is needed automatically. It is fully programmable with loads of parameters and does for example

  • start the Generator automatically when the battery drops below a certain programmed voltage (manual start possible as well)
  • charges the battery with up to 90 Amp according to programmed parameters
  • automatically inverts from 24 VDC to 230 VAC when shore power or generator power or both together are insufficient for whatever you need it for.
  • simply delivers 24 VAC when it is needed here or 230 VAC when it is needed there, provided the battery is not low.
WPC 24/3500-90

Whisperpower WPS

 

This system alone should be able to power our Arrow 1200 up to almost cruising speed (90 Amp output). The Generator is then loaded with 2.3 kW. There is still 1.2 kW power left to install another 30-40 Amp with an additional charger if needed. But of course we need a buffer, a battery suitable for our system. It must a) be able to deliver up to 300 Amp DC at 24 V and b) be able to supply power to go full throttle for some time, let´s say at least half an hour. When you see the figures it is pretty clear, that even deep cycle AGM lead acid batteries are not suitable. To go 30 min at full throttle you need 150 Ah. Considered not to discharge a lead battery more than 50 % you need a battery bank 300 Ah/24 V – which weighs 180 kg – nonwithstanding that a current of 300 Amp will destroy the battery within a few cycles. The answer is Lithium, in our case Lithium Iron because of the minimal fire hazard. Unlike Lithium Ion (Tesla) the Lithium Iron batteries contain to little Lithium for a severe fire or explosion. Nonetheless you have to be careful and never ever short circuit these batteries. The nominal voltage of the batteries is 13.6 VDC, not dropping even at high discharge rates. Greenstar sell their own range of Lithium Iron batteries which are basically relabeled Super B´s.

Super B 12V160Ah

Super B 12V160Ah

Now what is important about Lithium Iron batteries. Unlike lead acid batteries they do not need to be fully charged and discharged every time but it is crucial to never overcharge or discharge them. Once deep discharged and they are dead! This is valid for the single cell of the battery, e.g. a nominal 12 VDC Super B is made of 4 single cells and their voltage must not get out of a range of 2.5 V to 3.65 V. Lithium Iron batteries out of the box like the Super B´s have an integrated BMS (battery management system) which monitors these parameters, balances the individual cells and cuts off either the charging current or the discharging load to prevent the battery from damage. The parameters that influence the cycle life (No of cycles of discharging/charging) are a) the DOD, depth of discharge in percent and b) the charging/discharging current. To get as much as possible out of your expensive batteries the DOD should not exceed 80 % of the nominal capacity. The charging current should not exceed 1C  (means 1 x capacity, e.g. 100 Ah battery, max charging current 100 Amp) and discharging current should not go further than 3 C. Less is always better. The maximum size for a Super B LiFePO4 battery is 12 V/160 Ah. We need at least 2 of them connected in line for 24 VDC. Charging them with 90 Amps equals 0.56 C which is OK. Discharging them with 300 Amps (Full throttle, no Generator running) equals 1.87 C- not perfect but acceptable. 80 % DOD are roughly 130 Ah. For that we get 25 min full throttle only on battery or 75 min at cruising speed. These numbers increase when the generator is running. All in all it is not perfect! The biggest advantage is that I buy from one dealer/distributor which is of course better in case of a failure and guarantee. Still, for the same amount of money I can buy an individually configured battery system with BMS made of Winston LiFeYPO4 single cells with 400 Ah capacity.

Winston 300 Ah LiFeYPo4 cell

Winston 300 Ah LiFeYPo4 cell

The advantages are obvious. Lower charging/discharging rates, lower DOD, resulting in higher cycle life. The range without the help of the generator is extended (about 3 times as long). In addition they work at a slightly higher voltage. The weight: 2 Super B 12V160Ah 60 kg, individual bank of 8 Winston LYP400 with BMS 110 kg. If I reduce to 300 Ah it is 80 kg.

Bottom line:

We want to keep our catamaran light which is crucial for a good sailing performance. If we sum up all the weights (regardless the shafts and props since they are the same) we have for diesels

  • 2 diesel engines with gearbox and motor mount – 220 kg
  • 2 55 Ah starter batteries – 36 kg
  • cabling, wiring, exhaust etc. 20 kg
  • about 280 kg in total

Electric installation

  • 2 electric motors with motor mount – 35 kg
  • Generator M-GV4 pcc. with PMG – 76 kg
  • 55 Ah starter battery – 18 kg
  • WPC Charger/Inverter – 28 kg
  • cabling, wiring, exhaust 15 kg
  • roundbout 180 kg

The weight for the battery is about the same, e.g. 300 Ah Winston indiv. batt. bank 80 kg, 300 Ah 12 V AGM 90 kg. The diesel tank remains the same but we might not always fill it up to the top with the small consumption of the generator. If electric cooking works we spare the weight and the hazard of a gas installation. A total saving of about 100 kg should be possible.

The initial costs for the installation are higher than with twin diesels but the follow up costs should be a lot lower. We can produce electricity ourselves by wind, sun and – recuperation. From 5 knots boatspeed upwards the motors can produce electrical energy. With this it even might be possible not to run the generator at all.

Again, so far in theory. We are happy with our decision but only time will tell if it works out … The delivery of the parts start beginning of May, it´s going to be an interesting summer 😉