Building a Foam Core Powerboat

Reusing vacuumfilm: An improvement

2008-09-12T11:40:00.001+02:00

I Improved my table.
Vacuumfilm as well as tackytape is expensive. To uncover the readymade parts I had to rip the film and the tacky gets lost. A lot of good material for the dustbin!
So I tried the following: I pasted on the rim of my table draught-list. I bought a yard of film that is used to make ponds. I did cut 4 strips of it, some 2 inches wide and sealed them together with an iron-heater so that the rectangle fits exactly to the rim of the table. On this rectangle I "tackied" the vacuumfilm.
Now I have a covering compound film that can be clamped to the table, on top of the draught-list using alumium strips and tableclothclamps.
A test showed that my pump switches on only 8 to 10 seconds every 40 minutes. Excellent for my purposes. Now I can take off the film by loosening the clamps and reuse it the next time. No extra tacky needed.
By the way: I finished in this way all interior parts of the frontside of the boat.

Working at the table

2008-06-16T11:06:00.009+02:00

After working with Adrie for some time, I learned a lesson: Infusion is not the way to go to make simple small parts. To infuse a panel of, say, 10 square ft, leaves you with a relative big quantity of resin in the overflow bucket. In such cases the method is not only cumbersome, but also expensive.
A better way is to make such panels on a 'vacuumtable', which is in effect little more than a table that has an airtight surface. The panels are made by hand lay-up on the table and immediately covered with a bleeder cloth and vacuumfilm that is glued to the edge of the table with 'tacky-tape' (butyltape). After that vacuum is applied to the whole package and the resin is allowed to cure before the pressure is released. The result is absolutely comparable in quality with that of the infusion method. As I do not have to handle or move the panels during this process, it is clean too. Of course I handle one side of the panels at a time. After curing they are turned over and the process starts again.
I constructed my table with two simple and cheap 'board doors', available at the DIY-shop for about € 24 each. I glued them together obtaining a surface of about 6.5 * 6.9 ft. Big enough to make almost all of my flat panels. I covered the table with one layer of 450 gr biaxial glass and epoxy resin, to make it airtight. I ran a test before actually using it, and it turned out to perfom amazingly well: It took three (3!) days to lose the vacuum after I had switched off the pump.
I expanded the construction by adding a 'rig' for a tent, covering it. As soon as I am ready with the hand-layup and the vacuum is applied, I set up the tent and blow in hot air. In this way the epoxy cures really well and fast.
To connect the vacuumpump to the table I use a suction cup from Festo. As it will not 'suck itself' tightly enough to the covering film alone, I found out that an old CD will do the trick: Punch a hole in the film, stick the disk on it with tacky and the cup will have all the grip it needs.
See you next time!

A whole new setup

2007-07-24T13:52:00.000+02:00

I did mention that I am currently running an apprenticeship with Adrie Pijnen, shipwright. He is a frontrunner in the application of vacuum infusion, so there is a lot one can learn from him. He is also a nice man, happy to show what he has found out. He builds his own (but also many for others) vacuum installations.
I showed him my concoction. He laughed his head off. Such a little pump! A gastank! A vacuum advance unit for a pressureswitch!

I'll make you a tank, he proposed. Complete with all the connections to build a serious, however tiny, installation.
He welded a tank, 45*25*20 cm (17.7"*9.8"*7.8"). My little Robinair tightly fit on the top. Two valves, the pressure gauge, a connector for the pressure switch and one more connector in reserve. (Adrie, many thanks for this beautiful installation!)

He also gave me two ready to use pressureswitches. For him they were not applicable: Too little switching power, but more important, almost no hysteresis. The points at which the pump was switched on and off almost coincided. (In that case the pump switches on and off so rapidly that it will soon break.)
I took the two switches and put them together with a relay. The result looks funny, but in fact works very precise. The left switch controls the pressure at which the pump is turned off, the right indicates the point on which it is turned on again.

I am able to get the points as close as 0.04 bar together! (But also as far apart as I might wish)

I suppose I am ready now to experiment with my first injection.

A DIY pressureswitch

2007-07-23T12:40:00.000+02:00

Ever heard of a "vacuum advance unit"? It's a small device used in car engines.
Has something to do with the ignition moment. It is a small "can", equipped with a membrane attached to a lever. It has a tubeconnector at the side opposed to the lever. See also the picture. It can be used to make a pressureswitch yourself. Here is what I did:
I connected the vacadvance to some copper piping built in a wooden box. The vacuum pulled by my pump is applied on the unit and therefore it retracts the lever. The lever in its turn operates a switch. (See the second picture) The whole contraption can be tuned by tightening a spring.
To get some feedback I mounted the pressuregauge on top of the box.

See the third picture for the end result. It works like a charm!.....

However.... The switch has a wide range of "hysteresis". In this case it means that the points at which the switch kicks in and out are a bit too far apart. On operation the pressureswitch switches the pump off at let us say -0.9bar. It switches on again at -0.7bar. Rather wide apart.

It will do for the time being, but when another solution comes by I will give it a serious consideration.

A provisory vacuumtank

2007-07-22T17:41:00.000+02:00

I arranged a tank. It's an old propane flask. The tank serves as a vacuum buffer. The next component is the vacuum switch. Tomorrow more about that.

Vacuumpump

2007-07-18T10:45:00.000+02:00

I bought a pump. It's a Robinair 15151 (European 230V/50Hz version of the 15150). It can pull a deep vac that is quite sufficient for my app. I bought it over the internet at Fotronic. Only $ 133! (If I had bought the pump over here it would have cost me some € 700!!)
Next I need a vacuumtank and a pressure-switch. I'll come back on that soon.

Apprenticeship

2007-02-28T15:32:00.000+01:00

Currently I am doing an apprenticeship with Adrie Pijnen.
I will come back on this soon.

My Shopping List

2006-11-07T11:00:00.000+01:00

Long time, no see!
I spent my time working on a component list. You can go there by following the link "My Shortlist" on the right. I did my best to list every component necessary to build the boat. I have to admit, it dazzles me too!

All this has to be acquired. So this list is also a shoppinglist. Therefore, specially for my Dutch visitors: If you can advise me where to get all this the cheapest, (hey, we're Dutch, after all!) let me know!

I don't pretend to be complete, neither do I expect to have made the right choices. Please make any comment you feel appropriate. (Hit the links "comments" beneath every section in the list.)

Next week I'll be visiting the METS again. Many updates will come from that, I expect.

A visit during my holiday

2006-08-01T13:48:00.000+02:00

During my stay in Flims (Switzerland), last month, I took the liberty to pay Otto Holborn from Tecnautic a visit. Tecnautic builds steering systems for yachts for more than 25 years.

Being there I had the opportunity to get acquainted with the look and feel of the In contrast with other autopilots the steering wheel of Tecnautic "determines the rate of turn of the vessel (the wheel does not determine the rudder angle). When the wheel is in the centre detent, the heading is held. The rudder is moved automatically by the Autopilot Computer. This is the principal operating mode."
Of course this is not the only mode: the rudder position can be controlled directly by the wheel (not used very often, according to Mr. Holborn), while it also offers Autopilot and Navigation modes.

Besides offering an alternative for the traditional helm, Tecnautic makes it possible to control the engine(s). Throttle and clutch can be operated in an integrated way from the helm station.

The technology, Mr. Holborn suggested, is comparable to that used on (large) commercial vessels. Roughly speaking, Tecnautic only differs in price (only a fraction of the professional versions) and service (That is: they won't send a helicopter to repair your autopilot within 12 hours in any outskirt of the world. They do however give excellent telephonic support!)

Email

2006-03-23T14:19:00.000+01:00

As it seems that some of you are trying to get in contact with me, I added an email address under 'My Profile'.
Please feel free to use it!

Guus

A BIG infusion

2006-02-26T11:47:00.000+01:00

Last Friday I was invited by Arjen Koorevaar of Polyworx to be the guest of Pantera Yachts in Waalwijk, the Netherlands. They use Polyworx' software and Koorevaar coaches their infusions. They build huge power yachts, ranging from 76 to 108 ft. The total process takes about 4,5 hours.
I watched the infusion of an 76 ft model. It is constructed from a balsa core, with Kevlar layup and epoxy. The infusion of this giant is done in only one shot, inside and outside at the same time.
Carl van Esch, CEO of Pantera, assured me that in this way the theoretical limit of structural perfection can be reached for 99,5%. Hand layup will always leave air bubbles, in this way all air is removed from the epoxy.
As the infusion is done in one single shot, van Esch doesn't fool around experimenting: "Before one wants to start such a project, you have to be pretty sure it will deliver a success. The Polyworx software gives me that reassurance."

Stichting Maritiem Kenniscentrum

2006-01-19T16:12:00.000+01:00

This morning I payed a visit to Max Duursma & Jacob Gieze of SMK ("The Maritime Expertisecentre Foundation") in the far north of the Netherlands. These men work with prolonged unemployed people to train them and get them into jobs in the yachtbuilding business. And yes, they use vacuum infusion! And what's more, they cooperate with Polyworx to realize the perfect infusionplan. Currently they build a yacht that they developed themselves. Soon they will start a commercial wharf (employing their trainees) that will produce this yacht in series.
I went there to find out if they can help me doing the infusion. So it seems. On showing them the plans for the Hawk41 they were very interested in some form of cooperation.

Point of no return is passed.

2006-01-16T13:07:00.000+01:00

I signed the contract with Peter Bosgraaf (the naval architect) last Friday. The point of no return is therefore passed. Now it is going to be serious. Got to hire an unused barn, shed, greenhouse or stable or something. Got to get vacuumequipment.
I fiddled a bit with the Polyworx software, but I didn't manage to get the knack of it. Two weeks tryout is really not enough. (Not for me at least) However, the little I could do convinced me definitely of the value of this software. So I'm going to have serious talks with Polyworx this time.
Next Thursday (the 19th) I am paying a visit to "Maritime Knowlegde Centre", a foundation that perhaps can assist me with the infusion. We will see...

RTM-Worx?

2005-11-21T10:14:00.000+01:00

Now I have to come back on my visit to Mets. As mentioned before I met Arjen Korevaar. He delivers a software program called "RTM-Worx". This program makes it possible to emulate the infusion process on a computer.
Henny insisted that the 'amateur' cannot do without this program. The materials are just too expensive to run the risk of a failure. Although the setup of the mold, the foam core and the glass fibre layers can be done at ease, and corrections can be made any time, once the infusion process has started the point of no-return is passed. It has to go well or all material is lost. Some testing in the 'virtual world' is therefore a must.
Got to get a copy of that software!

I witnessed an Infusion!

2005-11-21T09:55:00.000+01:00

Yesterday I had the honour to be the guest of Henny van Oortmarssen, who is building a 39Ft. trimaran in his garage. What an astonishing experience!! Henny also maintains an incredible site on the subject!
The Fram is made from a foam core of 'CoreCell' and epoxy, using the 'vacuum infusion' technique. I witnessed the infusion of the outer layer of a float, which was done in a single shot. He uses a surpisingly little vacuum pump, that formerly operated in some laboratory.
Yes, I am completely convinced now that for me this is the way to go: the process is absolutely clean and delivers the theoretical quality limit. Hand lay-up cannot ever reach this!

The people that I met

2005-11-17T09:45:00.000+01:00

Visited the Metstrade Fair yesterday. This is a BIG fair!
These are the people I met (among others):
Arjen Korevaar from Polyworx, Iman Padmos from Padmos Steyr Motors Benelux, Leigh Michau from Q-SPD; Rob Wink from RobWink Serious Seatools and Pieter A. van der Weide from the European Certification Bureau Nederland BV. I also met Peter Bosgraaf who was accompanied by Daan Kornet. The latter is studying the possible choices with respect to the drive. I suppose he will be the one who is going to decide if the QuantumDrive from Q-SPD must be the way to go!
The coming days I will come back on my conversations with these people.

An invitation for Metstrade

2005-11-08T16:04:00.000+01:00

Looking for a drive that might propel the boat in the most efficient way I surfed the web for "Surface Drives". Thus I stumbled on DINTRA, the dutch representative for Q-SPD.
They (Dintra) were so kind to invite me for this fair, which is most appreciated!
In the second half of next week I will report on my visit.
For your information: I added links for Dintra, Q-SPD and METS to "My Links".

a Menu on the 'SideBar'

2005-11-05T19:18:00.002+01:00

I added a menu on the sidebar. These links will refer to parts of the boat or the building process. Under these links I want to aggregate all my posts concerning a specific subject. In this way you will be able to get direct access to all my posts no matter how old they are.
(Currently only the 'Introduction'-link is working. It doesn't give you any serious information yet, however...)