Hanoi Private Boat Yards

About Us
Our Boatyards
Our Technology
Our Designs
Modul Classes
Our Builds
Projects and Series
Contact Us
To Build Boats With Us
To Get a Boat From Us
Album and Library
Site Map

Boxy Cat 1

Friday evening, TGIF! His wife has already packed the bags with the supplies for the weekend. This time it is only the two of them. The last time also their teenage daughter joined, together with her girl-friend.
They are heading out of the noisy town, to the river, canal, or large lake, where their floating weekend camper is moored. They are expecting some quiet days, with swimming in the clear waters, maybe some fishing, and just enjoying the scenery. No need for thrill. Nevertheless, the boat was fast enough to reach that nice spot some 100 km (or say 70 miles) away by the evening, if they just start early enough the next morning.
After a short drive they reached the spot where they had left her the last time.

There she was. 19 feet (5.7 m) long, and 10 feet (3 m) wide. Except for the proprellers her draft was less than 1 foot. There will be few places, where they couldn't beach. Since the local laws limit the engines to 15 HP, when designing her, he had to take care to reduce the aerodynamic resistance so that she would not be blown away by the first head on wind.

They have their own cabin in front, with standing headroom on both sides of the 5' (1.5 m) wide berth. His wife demanded "reasonable" facilities, which meant a separate head, with full-height shower, accessible directly and privately from their cabin.
The dinette aft can sleep up to two guests. In this case, for the night the space in front of the back door is separated by some curtains, with a Porta-Potti style toilet.

He was assembling her over the last couple of months. In the city he has no reasonable workshop, let alone much time to build. He therefore ordered a local tin smith to build 4 canoe-like modules, two with rocker for the forward sections, two simple boxes for aft. They are each 8 feet long, 2 feet wide, and one foot deep. By this they could use standard 4 foot wide galvanized sheet metal to build them.

He could use his car with the roof rack to bring the modules to the lake where he assembled them. (Later, when he saw that the whole boat got a bit heavier than expected and the two floats were not enough to support the whole weight, he simply jacked her up like a car when changing the tire. He then disconnected one module after the other and glued about 4" (10 cm) of cheap styrofoam to the bottom of each of the floats. Then he added another layer of sheetmetal, with the sides of the cover glued to the sides of the original modules. This did not only stiffen the bottoms (a typical "sandwich" configuration), but also provided about 1200 lbs (more than 500 kg) additional lift.)
At the beginning of the assembly, after he had put the four float modules to the water, he first connected them by bolting them to a few strong wooden beams, along and across. He then placed some boards onto the cross beams to get the first working platform. In the following weeks and months he prepared the sides, decks, and internal walls in his tiny workshop in the city. His design was in such a way that everything consisted only of flat plywood panels, cut out, stiffened and strengthened with thinner and thicker beams, and then transported to the assembly site on the water, where he would connect the panels with bolts. Close to the waterline, where waves might reach the connections, he added silicone glue before bolting the panels together. Only a few pieces were pre-assebled "3D", like the front panel, as well as some cabinetry. But all of those parts were still small enough that they could be easily transported on the roof rack, or by a small van. For the interior, to save construction time he bought some cheap shelves "off the shelf"; he could replace them later on anytime he wanted.

Regarding propulsion he was considering some different options.
The easiest was to mount an outboard engine on a bracket at the centre line. This had also the advantage of adding little to the draft of the floats. But such an engine was easily to be stolen by night (a real danger in his country).
The other option was to install small inboard engines into the two floats. There was enough space available, e.g. for converted engines of silent motorbikes.
He was even considering electric propulsion. Two standard 220 V motors of a few kW in the floats, and a genset mounted on a tender, pulled for noise reasons in some distance behind. The genset would also charge the batteries for the lights and electronics at night.

After a while, some friends heard about his weekend-getaway and wanted to join him. The boat got a bit too small. However, to lengthen her was no problem. Just open the bolts, add two more 8-feet floats in the mid section, some additional panels at the sides, and she was 8 feet longer. Two feet were used for a small porch behind. This made it easier to board her, when entering from aft or the side, and also from swimming. And of course it made fishing a lot easier. Three feet were spent on a real bridge, i.e. a raised floor with the bench serving also as a capitain's bunk. By this he could hire a skipper and rent his boats to others. The remaining three feet were added to the galley, another small head, and the dinette.

End of the story? Not yet. He had to move, or simply wanted to relocate his boat to another area. Easy.... open the bolts, put all the panels and the floats onto a van .... and off she went ....
In fact, he could make a whole business out of it, since shipment was easy ....

.... and so he dreamt happily ever after ....

... until he started to re-consider some issues with the floats, partly based on comments in a boatdesign forum.
The results are listed on a page about the planned Technology.