Easy to build 25' power cat

[rob denney]

The T60 is unique.
It is a foam/fibreglass boat built with no cutting or grinding of cured laminates and no wet laminating. Not quite clean enough to build it in your living room, but not far from it.

The process is explained at http://harryproa.com/?page_id=1327, including animations. It has as much in common with IKEA assembly as it does with conventional boat building, but with glue to hold it together instead of screws and bolts. Required skill levels are low and the finished job is of a higher structural standard than most production boats.

The T60 is 25'/7.5m long, has seats for 6 people, space for 12, weighs 200 kgs/440lbs, has a 40 gallon/150l fuel tank and is suitable for outboards from 15-70 hp. This one shown is the tender for a 60' harryproa. A wider version is being built as an all weather dive boat. Other sizes and boat types are in the pipeline.

 

[Jim Caldwell]

Nice job Rob! That's some good out of the box thinking. when can we expect some on the water videos?

 

[Doug Lord]

Very, very cool Rob! That is just terrific.....

 

[gonzo]

The skill level for infusion is very high. The article make it sound like you can just mix resin and somewhat magically, the laminate is done.

 

[Jim Caldwell]

Actually, once you compute the flow rate and path mine have been that simple.

 

[rob denney]

The skill level for infusion is very high. The article make it sound like you can just mix resin and somewhat magically, the laminate is done.

The first sentence of the building instructions is:
"Do not try anything new until you have tested it on a small scale."

Once you have done a small infusion, and are aware of how the resin flows, then larger infusions are indeed "somewhat magical". And if prepared properly, less likely to be problematic than large hand layups.

It is critical that everything is prepared properly, but you have no worries about wet edges or resin curing too quickly so there is plenty of time to get it right. There is no secret knowledge or skill required. The resin flows towards low pressure and always takes the easiest path. Once this and a few rules of thumb are understood a perfect infusion is almost a given.

There are a number of things that can go wrong if the instructions, common sense or experience with the small samples are ignored. Apart from a power cut or incorrectly mixed resin, none of them are terminal. Almost all can be fixed during the infusion, the others will require either a second bagging or in extreme cases grinding out and replacing laminate.

Infusion is a rapidly improving process. What was once normal is not required any more. Examples are infusion medium and resin traps. The former has been largely replaced by scored core. In the latter, the resin is highly unlikely to reach the vacuum outlet, much less in sufficiently large quantities to need a trap.

 

[Jim Caldwell]

Leaving about 2" of peel ply past the edge of the laminate as resin brake works great!