OPC Tunnel P-Spec Build

[Travis Benjamin]

Good Morning,

I started this build thread on another forum although I think their are more experienced boaters here on IW that will have more to offer on a OPC Tunnel build. Don't get me wrong, I did get some feedback that was very valuable. Anyhow, here's the build. All suggestions/advice/feedback are welcomed.

Aquacraft TS3 w/ O.S. lower unit

 

[Travis Benjamin]

First I reinforced the transom at places I've been told they tend to crack. First I sanded the areas I wanted to apply the CF Cloth. Then applied the CF cloth

 

[Travis Benjamin]

I cut out the area where the radio box will fit. This also gave me access to the inside of the transom so I can reinforce the transom from the inside.

 

[Travis Benjamin]

I chopped up some scrap CF and packed in the voids in the transom, then added enough resin to wet out the fibers generously.

 

[Travis Benjamin]

here i've fitted the radio box that I designed on CAD and built up using 3/32 ply and basswood. I cut the lids from 0.093 plexiglass.

 

[Travis Benjamin]

I got some advice as far as blueprinting the sponsons. What I decided to do is sand the bottoms using my steel plate sanding block I made for printing hulls. I sanded the sponson as much as I could until the glass started to show through. There was still a small low spot along the center of the sponsons so I rough sanded with just paper and I re-molded the bottoms. I do this by placing a piece of wax paper on a large piece of glass. The mix up a generous amount of finishing resin and spread it out into a long line on the wax paper making sure it is as long as the area that needs remolding. Then I set the bottom of the sponson in the resin and apply pressure so that the resin seaps out at the sides of the sponson. I set a heavy weight on top and let it set up. This fills the low spots using minimal amount of resin and reduces the sanding time required to get everything flat. the resin is setting up now so I'll post a pics once it's cured.

 

[Mike Culhane]

Travis, your build is looking good. From my experience you will want to get the battery against the transom. I run a Lynx and although it's not the same hull my CG is at 7 3/8. You may want to make provisions to set your battery back as far as possible. I would cut the area out up close to the transom to allow the radio box to slide all the way back. Make provisions so the battery can sit all the way to the back of the radio box with the esc on top. This should get you close on CG. You can always move your CG forward if need be.

 

[Travis Benjamin]

While the sponsons are being remolded, I decided to make a flex cable sleeve for the O.S. lower. I bent a nice smooth curve to fit and drilled 4 small holes in the lower end by the propshaft and swapped out the nylon liner for the brass. I did the same mod for a friend on a lawless and the liner had to be bent with the cable in it or else the cable would not fit right. The O.S. mod worked out a whole lot easier. After I did the mod for my friends lawless he never broke another cable. When he had the nylon liner he was breaking cables like a bad habit. For an oiler I just use a piece of fuel tubing connected to both pressure fittings, then fill it with marine lower unit gear oil I use on my OMC lower.

 

[Travis Benjamin]

Travis, Your build is looking good. From my experience you will want to get the battery against the transom. I run a Lynx and although it's not the same hull my CG is at 7 3/8. You may want to make provisions to set your battery back as far as possible. I would cut the area out up close to the transom to allow the radio box to slide all the way back. Make provisions so the battery can sit all the way to the back of the radio box with the esc on top. This should get you close on CG. You can always move your CG forward if need be.

Mike,

Thanks for the post. I designed the radio box so I could fit a 6000mah 4s under the ESC slide all the way to the back wall of the box. I tried to get the box as far back as possible but I wanted to still have access to the transom plate that's why its not all the way at the transom. Should I just not worry about it and move the r-box all the way back. The R-box is 2" from the back of the transom

 

[Travis Benjamin]

Mike,

I think I can move the radio box all the way back without changing too much. I just need to get the lower unit mounted before I seal the box in. I'll post a pic of what I come up with

 

[Travis Benjamin]

Okay I revised my set up. now the back of the radio box is almost touching the front of the transom. it's now 15/16 from the back of the transom.

 

[joey padgett]

Thanks for posting your build thread.

I enjoy reading and seeing others ideas

Boat is coming along very nice

 

[Travis Benjamin]

Thanks for posting your build thread.

I enjoy reading and seeing others ideas

Boat is coming along very nice

Yeah I enjoy building and sharing, especially when someone appreciates my efforts. Most of this work was done in the past few weeks. I'm outta town now but I brought it along with me so I could spend some free time on it. I really appreciate the advice that's shared here on IW.

 

[Mike Culhane]

Travis, mods look good. You will be in the ball park now. Keep up the good work!

 

[HOTWATER]

Nice job!

-Kent

 

[Travis Benjamin]

I am planning to use a Hi-Jack Outboard Mount on this build but I don't have it with me now. I was wondering if the transom mounting holes for the mount are the same location/spacing as the transom mounting holes for the stock mount on the O.S. lower. I'd like to get the outboard mounted so I can move on with the build, then when I receive the mount just bolt it up and go. Any help is greatly apprecitated

 

[HOTWATER]

Why not just use the OS mount? Thats how mine is mounted on my Vision FE.....

 

[Grimracer]

For sure.. just use the OS mount..

Grim

 

[Mike Culhane]

I'm with the guys on this one. OS mount is all you need.

 

[Travis Benjamin]

Okay, the votes are in O.S. it is. The only draw back is that I'll have to change the way I was gonna setup the steering cables becuase the hijack mount has a farther setback than the O.S. but I think I can make it work. I have a few days to come up with an idea cuz it looks like I'm not gonna be back home until the 2nd or 3rd of jan. I can go ahead and mount the lower and go from there. Thanks for the input. This is my first OPC tunnel build so i'm learning alot. I have already ordered and second tunnel that I will be starting next week. I'm really trying to get a local p-spec class started and I have stirred up some interest. I typically build all the boats for the guys at the local pond so my goal is to build serveral of these.