Ultimate 18 poptop conversion

Discussion on how to make that Trailer Sailer go faster & more comfortable
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ray on the bay
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Ultimate 18 poptop conversion

Post by ray on the bay » Sep 25th, '15, 21:04

Hi all,

I have been contemplating converting my ultimate 18 to pop top for quite a while. The boat builder has retired and handed the molds to the association, so I have taken the opportunity to take the next step. Ill post a picture book on the progress of this job (which is now 1/2 way through).

Some may consider an over investment, but others will understand, its not always about the money, the value is in the enjoyment & satisfaction of being creative and having an engaging hobby.

Zeb lives nearby and is also having fun being involved, and is a fantastic help. (thanks Zeb).


the first image is me getting in the mood to cut the roof off :)

Image
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ray on the bay
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Re: Ultimate 18 poptop conversion

Post by ray on the bay » Sep 25th, '15, 21:22

I measured a number of boats last year on one of our cruises. It was interesting to find that there were many slight variations in the dimensions of the cut-out of the roof, and raising posts.

the measurements were fairly detailed..

I looked everywhere and couldn't find them, but got to clean out some junk files during the search.

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Re: Ultimate 18 poptop conversion

Post by ray on the bay » Sep 25th, '15, 21:32

I had a pop top laid up in Dandenong, and supplied a couple of hatches for a custom gel coat colour match. It came out perfect match.

I still need to do a little more work on this part as I had it made a little thin and would like it a bit thicker so can be walked on confidently. Just need to lay another layer of matting in the right spots.

here's the virgin pop top out of the mould

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Re: Ultimate 18 poptop conversion

Post by ray on the bay » Sep 25th, '15, 21:36

the roof ribs are longer than the pop top and need to be cut off and refinished in gelcoat. We decided to do this first so can make better measurements (unobstructed) before making the cut into the cabin top.

I just uses a sabre saw for an initial rough cut.

Image

...and a close up (note the pencil line; the saw marks will be cut off)

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Re: Ultimate 18 poptop conversion

Post by ray on the bay » Sep 25th, '15, 21:42

I used an old timber blind venetian to mark the curved roof.
note we marked a reference point of the centreline of the boat.

Actually: in practice- we just laid the pop top on the roof and traced around it.
we then came in a distance and marked the lines for the cut.

we measured a few times and re adjusted a few times. check, double, triple check - think ahead - what will need to go where and do what and how will it work.\

check again against Playmate-- take a deep breath

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Re: Ultimate 18 poptop conversion

Post by barnaclephill » Sep 26th, '15, 08:20

ray on the bay wrote: Image
Halloween is next month Ray :lol:

I did my rooftop conversion with a jigsaw while sailing back from French Island. Made the (fixed) higher roof section from plywood and put it on top of the 2" high battens I epoxied on the roof. Then did the sliding hatch.
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Re: Ultimate 18 poptop conversion

Post by SeawayVolcano » Sep 26th, '15, 17:46

My RL24 'Pacemaker' has a pop top. The previous owners found it tricky to raise and lower safely but they put up with it for about 30 years. Within a week of owning the boat I solved the problem and now it is easily raised by one person 'safely'.

Depending what means you have of raising it and keeping it up and preventing it flopping around, what I did might be handy. I'll try to remembe to take some photos tomorrow, but basically there is a U shaped (well a sort of flat U) piece at the front of the pop top that provides a hinged support. The legs of this 'U' have traveller cars on the ends and slide into some traveller track on the insides of the opening. When you raise the front of the pop top, the hinging arrangement allows the legs to slide forward and you just flick the restrainy thingies on the traveller car and they lock into holes.
So raising the front is a one handed operation. But you have to hold the top forwards against its own weight while you raise the back. Risking broken fingers if a boat goes by.

The back is where the problems were because there can't be a U shaped hingy bar there due to the sliding compnaionway top hatch. So each leg drops down and its traveller car slide in a piece pf track sitting vertically inside the companionway hatch. In the past it didn;t matter whether the front was raised first or the back was raised first, The front of the thing was unstable fore and aft and the back was unstable fore and aft AND sideways until a paid of diagonal braces were fitted to the rear part. And then only the front was stable sideways. The back was still horribly sloppy side to side.

I looked at it. injured myself once trying to support the weight while hooking the diagonals and locking stuff.

So the first thing I made was a bracket each side at the companionway end. that did away completely with the need for the fore and aft diagonal braces while it completely removed the sideways sloppiness.

The second thing I did was modified the little locking thingies on the traveller cars. Normally you have to hold them out of the holes with one hand while you try to get each leg lined up. I modified them so I can simply twist each of the 4 about a quarter turn, locking them out of the holes. Then as I get each one lined up approximately I just flick them one at a time and the legs are supported. Then I might have to manually adjust some of them one hole if I've been slack.

this sounds complicated in words. but it is really simple. I'll see if I rememeebr pics tomorrow
Cheers,

RossD and Jo.

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Re: Ultimate 18 poptop conversion

Post by ray on the bay » Sep 26th, '15, 18:41

Thanks Ross. Am very interested in photos of this and also pics or diagrams of the fittings with the modifications for the pins.

Cheers Ray
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Re: Ultimate 18 poptop conversion

Post by zebedee » Sep 26th, '15, 23:09

SeawayVolcano wrote:...The back is where the problems were...

...The second thing I did was modified the little locking thingies on the traveller cars. Normally you have to hold them out of the holes with one hand while you try to get each leg lined up...
We spotted this issue and confirmed it is a hassle with Peter (Playmate).

The vertical struts on the U18 run on a length of about 600-650mm (varies depending on the total lift desired) of Ronstan 19mm C track.

Typically the slider with built in track stops is used:

Image

Using separate sliders and track stops would be easier to operate, but the poptop would need some sort of lockdown, since it could rise above the separate stops when down.

But then we spotted that the sliding hatch also runs on two 1060mm lengths of Ronstan 19mm C track without stop holes. A bit of investigation reveals this is no longer available and was probably a special order. The sliding hatch does not use track stops at all.

I'm trying to persuade Ray to spend a little more for a second 1500mm length of new track to provide two new 1060mm tracks for the sliding hatch, so we can cut down the stop-less tracks for the two ~600mm rear poptop struts.

We would drill stop holes to lock the poptop in the full up and full down positions. Additionally; Peter has advised that the raising sequence is:
  1. Rear up a few inches so the poptop doesn't foul on the rear of the cabin when the front is raised
  2. Front up fully
  3. Rear up fully
So we would drill a third stop hole on each track at about 100mm up.

Raising/lowering would involve releasing the stop, then lifting or lowering until it engages the next hole.
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Re: Ultimate 18 poptop conversion

Post by oldsalt » Sep 26th, '15, 23:38

Your might want to consider aluminium T slot fittings as they are much cheaper and there are all sorts of slides and catches and the chances to drill only the holes you want. This is just one link for an example


https://mcjing.com.au/categorybrowser.a ... eSupport=1

I am aware that stainless is less prone to corrosion but the anodised T slots my son has used on his 4wd ute have proven to be very corrosion resistant.
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Re: Ultimate 18 poptop conversion

Post by zebedee » Sep 26th, '15, 23:50

Curiously I have a friend whose workshop is where all the woodwork has been prepared and who is about to buy that T-track from Carbatec for the router table we've just built, so we might get a better look at some soon.
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Re: Ultimate 18 poptop conversion

Post by ray on the bay » Oct 6th, '15, 00:39

the cut....
that's Graham smirking because he has got away with cutting someone else's boat...hey that's mine :(

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Re: Ultimate 18 poptop conversion

Post by ray on the bay » Oct 6th, '15, 00:43

power file off the old ribs

Image


oooh... look what's under he mast base... i'll fix that while i'm at it.

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Re: Ultimate 18 poptop conversion

Post by Furstin » Oct 6th, '15, 11:41

Brave man....!

Looks good.
So whats the steps from here? I assume you have to laminate a frame around the 'hole'.
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Re: Ultimate 18 poptop conversion

Post by MoodyBlue » Oct 6th, '15, 12:44

I agree with Matt,

The first cut would have been a massive stress event to me!!!!!

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Re: Ultimate 18 poptop conversion

Post by zebedee » Oct 6th, '15, 20:27

That's why I did most of the cutting.

At this stage, all the timberwork is in place in the hull and epoxy coated except the rear track supports, and the poptop has been trimmed for fit to the hull. If we had the hold down fittings, we could put it on (but not raise it), sort the rigging and go sailing.

We're very close to fabricating the lifting mechanism next. Ray emailed me some more photos to host last night, but I haven't put them online yet (I'm on Dad's computer here).
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Re: Ultimate 18 poptop conversion

Post by Tumbleweed » Oct 6th, '15, 20:38

Are you guys almost twins?
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Re: Ultimate 18 poptop conversion

Post by zebedee » Oct 6th, '15, 20:44

Nope. Ray is the Stan Laurel to my Oliver Hardy.
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Ultimate 18 poptop conversion

Post by Tumbleweed » Oct 6th, '15, 20:46

Just the head on its own up the front of the trailer in one of the photos looks similar to yours :) although that could be a mystery third person.
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Re: Ultimate 18 poptop conversion

Post by zebedee » Oct 6th, '15, 20:48

Ahh, no.
Image

That head in front of the boat isn't Ray; it's an old mate of mine (we met in primary school!) who dropped by to inspect progress.
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Re: Ultimate 18 poptop conversion

Post by Tumbleweed » Oct 6th, '15, 20:51

I realized afterwards that ray would be the one holding the camera. :) mystery solced
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Re: Ultimate 18 poptop conversion

Post by ray on the bay » Oct 15th, '15, 00:23

timber is next... off to Bunnings and bought mirbau decking
Image

we biscuit joined and epoxied some of the planks so can make the curved piece for the front of the cabin
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the timbers were cut and screwed into place before the final epoxy gluing process
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Re: Ultimate 18 poptop conversion

Post by ray on the bay » Oct 15th, '15, 00:27

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Re: Ultimate 18 poptop conversion

Post by ray on the bay » Oct 15th, '15, 00:31

I need to stiffen up the pop top a bit, so I cut strips off the redundant roof that was cut off.
I used the strips to fill the slots and mixed the dust into a polyester resin filler.
I'll lay some chopped strand matting to the bottom of the pop top after the fittings have been sorted out and we know what clearances we have to play with.

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Re: Ultimate 18 poptop conversion

Post by ray on the bay » Oct 15th, '15, 00:35

while I'm at it I might as well sand off the old cracked up varnished timber work and epoxy them up.
I am using bote coat epoxy which is non yellowing.

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