MK1 Hull #61

[Andre]

Lou has ashed some questions about the hatches and ports on my Telstar. The ports are Bomar set directly into the lexan side window. I used 1/4 inch Lexan and it works just fine. If I had to do it over I would opt for something thicker, Lexan seems to be way more flexible than acrylic. I set the Lexan windows in place by creating a fiberglass step inside the cabin and directly bonding them, no fasteners were used. I also added a hatch in front of the cabin entrance to increase light and ventilation.

[petrel]

andere,

I was curious about your hatch modification also. Thanks for the great photos. Your boat looks really nice with high quality modifications that add to the overall boat's appearance. Not easy to achieve.

I notice you have replaced your wooden grab rails with stainless steel pipe. Something I have been meaning to do for a while. How are they fastened?

Thanks
Geoffrey

[Andre]

The old wooden handrails were screwed to the riser pads. The pads have a wood core. The new handrails are 1" tube. To fasten the tube I drilled 1/4inch holes through it and welded in long 1/4in studs. The studs go through the pads and deck and fasten inside with nuts and fender washers.

Andre

[Dan]

I'd point out that Lexan is really not the best material to use for ports. Cast acrylic is far better. It is more scratch resistant, more UV-tolerant and most importantly, cast acrylic doesn't distort the way polycarbonate does under impact. This is why all the major hatch manufacturers use acrylic, not polycarbonate, with the exception of one line of Bomar hatches. However, the Bomar hatch has reinforcing bars to prevent the polycarbonate from distorting and breaking the seal.

I'd point out that using acrylic glazing is also the recommendation of Tony, from Select Plastics, which is one of the largest and oldest aftermarket port/hatch replacement manufacturers.

I recommend using one of two bedding compounds for large ports and hatches. The first, and one I prefer, is Dow Corning 795 silicone, which is a structural adhesive specifically designed for bedding glazing materials in high stress applications. The second is Sikaflex 295, which requires the use of the 209 primer IIRC.

Tony, from Select Plastics, says the following regarding bedding acrylic and polycarbonate glazing materials.

Well here goes... The only three adhesives I would consider using are Sika Flex 295 UV with the primer, GE SG-4000, and Dow 795. Using the correct adhesive is only 1/2 the battle. Do not apply the sealants below 50 degrees F. The temperature must maintain at least 50F during the entire 21 day cure cycle. Cut this corner and your finished before you start. Preparation of the bond area is also very/ very important. DO NOT TOUCH THE BOND AREA WITH YOUR BARE HANDS! Contamination from the dirt and skin oils will make a solid cure impossible. You may clean the FRP and metal with acetone to prep the area but if you touch the Lexan or Plexi with harsh solvents you will ruin the portlight. A 50/50 mix of isopropal alcohol and distilled water will work well to clean the plastic if needed. Remember that clean enough is not clean enough.

[luigisante]

Not sure how I did this duplicate post.

[luigisante]

Thanks Andre. Your's is one of the nicest Mark Is I've seen. I like your modifications. I don't know if I have the guts to cut my Lexan after all I went through to install it. But, I am putting a small hatch exactly where you put yours for ventilation and I am doing the cabin ceiling like yours is done. Your solution for the halyards is great as well. What size are the winches on the coachroof top?

It looks like your ceiling has panels that are screwed in between the wood trim that span the width. I was thinking about Velcro to make the panels removable but the screws would be better with grommets if the balsa core will hold them. Are those panels made of masonite? Formica? Did you have to do anything special to prepare the ceiling?

Finally, how do you like the main sheet traveler track on the coachroof? I've considered this as well. It would make more room in the cockpit if it did not make controling the boom harder.

Sorry for so many questions, but your boat is so close to mine (9 hull #s). There are things I have wondered about, such as the location certain trim pieces I have lying around.

Lou

[isaacsman]

Lou,

In Newsletter No.9, Feb 1988, Eric Branton describes in detail how he did the modification on Rose Cottage. I don't know if you have access to the early association newsletters. I have copies of them all but I don't know how to upload them. I modified my own Telstar, a Mk.11, some twenty years ago. It was all very straightforward, the load on the mainsheet feels the same, the space in the cockpit can be fully utilised. I have an inboard outboard and access to this is much easier. I fibreglassed the three removable panels into one and when removed this fits snugly in the well.

Mike

[Andre]

Lou
Thanks for the compliments.
The winch on the cabin top for the halyards is a Lewmar #6 it works but really should be slightly larger. The cabin overhead panels are 1/8 plywood covered with white vinyl. The ply is screwed to the overhead beams. The beams are a T section so the screws do not go into the balsa but the top of the T. To install the beams I sanded the area where each beam would lie. The beams were made from 3 strips, the first against the overhead was 3/8 X 2 inches the other 2 were 1/4 x 3/4 all glued with epoxy. I cut some 3/4 x 1 inch props and wedged the beam up tight to the overhead. To make the ply panels I used cardboard and tape to make a pattern and cut out the ply. Each panel took many test fits before I was satisfied. The aft hatch has its own wooden trim ring in the same T section and it to is epoxied to the overhead.The aft edge of the rear panel is screwed to a 3/8" X 2" strip epoxied to the overhead. The forward edge of the front panel is tucked under the fiberglass mast beam support cover. Forward of the cover the vinyl is applied directly to the overhead with contact cement. This area has a compound curve that wold be hard to match with plywood. I also was unwilling to reduce the headroom in this area. I like the way the overhead turned out it hides the fasteners for the deck hardware and is easily removed for maintenance or to add hardware.

The load on the main sheet is not at all high with the mid boom sheeting and I have never had a problem controlling the main. I know there all sorts of arguments against mid boom sheeting but in my case I couldn't be happier with it.

[luigisante]

The wooden "T" is brilliant. I had already concluded that the wooden strips and panel inserts were the way to cover the ceiling but the best I could come up with was to epoxy the strips and use velcro to attach masonite/vinyl panels. I like your solution about 1000% better. Thanks.

Lou

[luigisante]

Lou,

In Newsletter No.9, Feb 1988, Eric Branton describes in detail how he did the modification on Rose Cottage. I don't know if you have access to the early association newsletters. I have copies of them all but I don't know how to upload them. I modified my own Telstar, a Mk.11, some twenty years ago. It was all very straightforward, the load on the mainsheet feels the same, the space in the cockpit can be fully utilised. I have an inboard outboard and access to this is much easier. I fibreglassed the three removable panels into one and when removed this fits snugly in the well.

Mike

Thanks Mike. I recall reading the mod to Rose Cottage. At one time I had all of the newsletters but I'm not shure where they have gotten to. I may change the mainsheet to the coachroof since I'm starting from scratch anyway.

Lou