JARCAT NEWS

AUGUST 2003

This month we look at other sites and comment on their craft. I am not criticizing their J6s but just putting in my comments based on my own and my families experience with our JARCAT SIX.

Firstly there is a great Yahoo Jarcat group section going on. This is magnificent advertising for which I have Robert McCarthur to thank. Robert and Jodie have a Jarcat Six themselves.

My only comment on this remarkable page which must have taken considerable time to assemble, is that the stainless steel self tapping screws should have been fitted before the glue sets. The screws apply the pressure to ooze some of the glue from the joint. (this is how I read it)

This J6 looks great. Lots of accessories.

There are some changes in the cockpit region which alter this J6 from the standard.

The seat top hatches with the solar panels on them will limit the seating on the seats.

They are also likely to leak unless done with care. (They may be wet lockers with a sloping floor to outlets into the cockpit)

There are also sloping seat backs on the back of the cabin. These add weight and work when building and may make it harder to climb onto the cabin top to go forward or work on the mast or whatever. I guess the long handrails are to help one around the side.

The hinged hatches giving access into the front lockers from inside would need to lower onto something, the stringer maybe? This would allow single-handed access without having to hold the hatch open.

The temporary timber at the top of the cabin side has been left in place. Looks better if this is removed after the cabin top has been fitted. Also less weight high up in the cabin.

The steering mechanism is impressive. I expect the cross-arm has the bend to allow the motor to be raised.

Metal to metal without bushes tend to wear out or bind. Thus the current thinking with the setup we run. Slots in the ends of the tillers contain the bolts from the cross-arm. Seem to work.

I can suggest you look at the above sites for basic information on what a J6 is and how to build a J5/6.

Recent plan addition, an "Exploded view" for both the J5 and the J6. This plan page gives a quick insight into the construction.

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Meant to write before ( as suggested ) about the windows in my J6. Having had a TS earlier with about 500 small bolts holding the windows in which always leaked & drew blood from my poor head on more than 1 occasion I
decided to try sticking mine on without bolts.
I extended the overlap between the plastic & cabin sides to 30 mm (1 1/2").
Using a temporary self tapper in each corner to hold the plastic in place while I marked the edges of overlap on the window & cabin. Masking tape was applied to the cabin side about 1mm outside the plastic. The plastic was
removed then carefully & I thoroughly roughed up the overlap on both the plastic & cabin side with 60 grit wet & dry. Two temporary wooden blocks were taped onto the cabin side for the plastic to rest on at the correct location.
A 12mm dia ( 1/2") bead of urethane sealant was applied all round the window in the centre of the overlap & the window offered up. The temporary screws in the corner were replaced & tightened up until the sealant just reached the outside & inside edges. With someone inside the windows were pressed in all around until the sealant reached the edges Any spot that looked a bit light on received an extra squeeze of urethane. A wet finger was used to smooth off the outside, then the masking tape was removed. The inside was left till cured then a scalpel was run around the perimeter & the excess urethane peeled off easily. When cured the temporary screws were removed & the holes plugged.
Two years on & no window leaks or fall offs. ( also no blood from little bolts)
It is essential that the sealant bed is AT LEAST 1 mm thick to allow movement without the sealant shearing.
I doubt that this would be a good idea with the curved front cabins due to inbuilt stresses but I went back to the Veed front ( as well as the twin hatches)
Don #167
ps My windows are actually tinted teflon coated polycarbonate, not perspex. I was sold on the superior properties of the poly before I found out the cost!!

Moreton Bay area,

Forbes Peters has launched his power boat J6 and it looks very good.

This version just uses a headsail, no mainsail, and a large outboard motor for when it is needed. Forbes & Bern are both retired folk.

There is easy walkway from the transom to the cabin with just two low steps to move over, about 40mm high where the transom used to be and where the outboard and cabin bulkheads were. To board the J6 Forbes has a drop down ladder coming off the port transom with a small outboard support built in. Then step onto the duck-board and up onto the cockpit floor next to the outboard well. Walk forward past the outboard and through the cockpit then into the main cabin. The main cabin is as per the standard J6 plan but lengthened by 10%. This 10% extension was applied to all the J6 but the Distance from Frame 3 to the outboard bulkhead was kept the same as it was. This allowed more support to carry the 25hp Two stroke outboard.

Forbes steers by a single rudder mounted on the starboard hull by means of a wheel on the entry Bulkhead. He sits up on a helmsman’s seat which is high enough to see out the upper front windows. There are still seats running for & aft either side of the cockpit. The last section being top opening and draining for access to the steering lines and wet gear.

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The other "launching was Keith’s J6 which had been used as a motor-boat until Keith purchased it. I was invited to sort out the rigging. There are many differences to a "standard" J6.

After a bit of messing around we got the rig up, attached the headsail and adjusted the travelers. There is a direct pull for the headsail sheets and no cleats for them. We looped it through a nearby deadeye to give it more friction to make it easier to hand hold the sheets.

Keith purchased some sheet rope for the mainsail and we eventually launched. The 8hp 4-stroke Evinrude looked heavy and Keith could not get it fully down. We motored out of Manly Harbour. Once outside I raised the mainsail to find it was off a different design. It was difficult to tension the luff with the 2:1 purchase and horn cleat. The mainsheet system was also on the small side and the 8mm line barely went through it. The purchase was 3:1 where as the usual is 4:1. Thus the mainsail was never working fully.

The wind was mediocre. By the time we were returning the wind was a bit more than mediocre. I took over control of sails and Keith took the helm. The wake changed, indicating a new speed, until we reached and the leads to Manly Harbour. I took the mainsail off. Rotating masts are so much easier than this fixed mast. Not much to alter though to make it a rotating mast.

We came in just with the jib for a few sets of markers then started the motor before entering the harbour itself. The jib was released and stowed as soon as we were on the sand next to the ramp.