Moebius Skipjack hull issue

[g2tiger]

Hello everyone,

I'm currently struggling with a Moebius Skipjack hull. I have the R & R Engineering WTC kit with the drive parts already glued in. My struggle is that the upper hull is wider than the lower hull creating an issue with mating the two together. I sanded down the thin lip on the one hull and removed the large alignment pins on both as they created an issue in my thinking. I next installed flat 1-inch plastic tabs alternating between the upper hull and lower hull. Even with the tabs the upper hull still is not very good. So I have two thoughts: 1. I am thinking about installing a strip on the outside of the upper hull along the seam to cover the openings and gaps but am not sure. 2. grind out the tabs and install a strip along the inside of the upper hull to bring it into alignment with the lower hull.

I did a lot of hot water and boiling water treatment to the hulls and I also did the dangerous heat gun treatment but the hull still is not quite right. You might see some hull warpage in the one photo. My next thought is to sell the whole thing and go a different route. I think that when I glued the two hulls they were not aligned exactly right. I'm sort of stuck now unless I grind out the R & R parts and get a new hull.

Any thoughts on getting the hulls to align? My usual experience is with Fiberglass hulls and the tab method works well for them.

[salmon]

May I offer some encouragement.
Those gaps between top and bottom are fixable. Use Bondo body filler. It will probably take several tries, and some sanding, but you will get there.
I am using a Metal Glaze by Evercoat, but Bondo will do as well.
It can be used where the hulls were joined.

Then same for the gaps. I use a metal shim, but run your Xacto blade along the seam before it gets completely set.

Sand it down and apply a coat of CA glue. This will help adhere the Bondo to the plastic and strengthen it too.

I butchered my Type XXIII and using what David Merriman showed me, worked great:



Hope this helps.

[g2tiger]

Salmon,

I had thought of that but was not sure. I did it on my Gato which is now all apart awaiting my attention to the rear end and creating a WTC both of which are a hot dumpster fire mess sort of thing. . Since the lower hull is more correct I will put the Bondo on that hull as the upper will need to be flexed more to make it fit.

Alas, I had thought of selling and buying a 1/48 hull from Deboer

[Ralph --- SSBN 598]

Suggestion.
Before filling the hull gap between upper and lower hull, build the inside frames and get them in place.
This will help hold the hull halves to shape.

My boat has gone through 7 or 8 modifications.
When I went from a "Z" cut hull to a centerline cut, I had to fill the gap on the bow. (mostly the gap caused by the saw cutting)
I used plastic strips glued on the hull edge then red filler.

How I did is in this modification build log.

http://www.cliffhangershideout.com/skipjack3/Skipjack-log-3.html

I have been think about finding a new kit and building it to match the last modification.

The boat can be trimmed at periscope depth. (1/2" out of the water)
Then I can control depth with the sail planes.
Rear planes are on auto leveler.
I have been known to run the boat at after trimming for 2 to 3 hours on just throttle, rudder and sail planes.

During your build, when you have an issue, come tell us about it.
There are several Skipjack builders that have gone through it.
You will most likely get more than one solution to choose from.
You can choose the one that works for your build.

[salmon]

I agree with Ralph.

[g2tiger]

Ralph, thanks for the encouragement. I have your build marked and tried to build my boat as you did. I also used cliffs as a guide. I think I need to re-read both. I did create a new brace from acrylic plastic (I think it was acrylic or possibly Lexington)) for the upper hull. Perhaps several more in the upper hull might do the trick and allow freezer tabs. I’ll keep everyone posted.

I wonder if any one could produce several sets of braces that are glued into the upper and lower hills that have alignment tabs in them. Glue them in the two hills and the help keep the hills round and also serve as alignment components.

[Ralph --- SSBN 598]

I build all my hull frames from 1/16" styrene plastic sheet. I cut pieces out with scissors and then bond them together compressing them in a big vise. Then I cut the center hole for the cylinder. Followed by shaping the out side edge to the hull dimensions.

I have several build logs covering each build I do. I even include the mistakes to show what I was doing and how it went wrong so others can avoid these mistakes.
Here is the original first build of the Skipjack.

http://www.cliffhangershideout.com/Skipjack/Skipjack-log.html

This link is to a page listing almost all build logs. (on the right side of page)

http://www.cliffhangershideout.com/subpirates/SP.html

As said, there are many ways to build a single project.
Take what you can use and leave what you don't need or have another way to do.

I have been at events where there might 4 to 7 Skipjacks with no two the same inside or out.

[g2tiger]

Ralph,

I am looking at McMaster Carr and cannot tell which plastic to order. I would like to duplicate your use of styrene plastic but there are a number of choices and none say they are styrene plastic but some other form of plastic. Can you provide some direction or a PN? I'd like to use that plastic as the tabs to replace the current tabs which I think are too thin.

Also, as I mentioned I am making the hull rib formers as you suggested prior to filling the hull gaps along the seam. It is tough going as I am using some clear plastic I bought for Home Depot which I believe is Lexan? Anyway, I use the R & R engineering WTC mount bracket as my template and then draw onto the plastic, cut it out with a Dremel tool then use a DA sander to sand down to the final shape. I completed an upper forward unit last night and will glue it in tonight if all goes well. One of two more toward the stern should bring it into shape, I hope. I also reviewed the link you posted that has all of your Skipjack mods. I like the change from Z cut to flat cut. Since I am in the process of working on the hull shape I wonder if I should try to re-work my Z cut. Any thoughts?

[Ralph --- SSBN 598]

The cylinder is from McMaster Carr.

https://www.mcmaster.com/polycarbonate/clear-impact-resistant-polycarbonate-tubes/

#8585K47

The styrene plastic sheet came from a Plastics company.
What I got was 1/16" thick by 4' by 8'.

For the centerline cut on the bow, I used a razor saw. The dremel saw cuts a very wide gap.

As for putting frames in the hull, I used the cylinder to make them straight.
Put the front and back frames in then adjust the middle frames to fight up against the cylinder and fill any gaps the frames have to the hull.

The last modification allowed me to use an Engel's piston ballast system.
Had to carefully file down the plastic frames on the piston to get the piston to slide in to the cylinder.

[g2tiger]

OK team,

I have made frames for the upper hull as recommended. The frames appear to have worked. There is still a gap but it is much reduced. One issue is that the rearmost frame was glued in about 1/8 inch too far back and it conflicts with the lower frame WTC rubberband securement tabs. I have a few photos of my process using the tools at hand. Here is how I made my frames. Before I glued in the R & R Engineering frames I drew them on some Manila folder materials. I used these as templates to draw and cut out the upper hull frames. Using a cutting wheel I made the basic cuts for the frame, then I used a DA sander to bring the outer edges where I wanted them and then the sanding drum to finish the inside of the frame. Once the frame fit as desired I used a mouse sander to sand off the junk paper and paint. The frame was checked several times for fitment and then glued into place. All I need to do now is figure out how to fix the lower frame so that I can somehow secure the WTC in if I remove the tabs used for holding the rubber bands.