Fishing Deck Extension Project For Older Tri-Hull Fiberglass Boat

[J-Doc]

Anyone ever wanted to do one of these? Never thought about it? Already did but want to redo it?

I just completed mine and decided to post a write-up and a few photos to documented the process, describe materials, how it’s built, etc. In case someone wanted to do this for their boat, shoot me a message and I can provide some help/feedback/ideas.

I will also share some things I've learned along the way that I would do different if anyone is interested.

Here is a quick video link of the final product for you attention deficit types (myself included)

http://youtu.be/BDWlzx7CDfo

So here we go....

1979 Cane Cutter 15.2 Modified Tri Hull

• Original seats wrapped on plywood backs were rotting
• Seats are a bit of a pain for fishing because you had to move the seats around when you needed access below for the factory storage
• Storage was little to none.
• I was always tripping over my tackle bag in the middle of the floor or other gear and wanted more "floor space".
• It was probably a wash in cost to replace the seats or build the deck extension. (I didn’t keep track but I’d say I spent an easy $400+ mainly due to hardware and not material – screws, hinges, latches, gas strut, etc. It all adds up super-fast even when you find great deals like I did)

Total weight added to boat:

• 40lbs (new deck weight, not gear added)

Waterproof?

• Yes!
  • Sealed top and sides with fiberglass resin
  • Sealed bottom side with Thompson’s Waterseal so water will quickly “drip off” and not soak into wood
  • Sealed all penetrations as best as possible with either Liquid Nail (waterproof kind) or 100% silicone
• Are lids waterproof?
  • Lids yes, contents below? No. I did not have time or desire to create drain channels so the storage compartments can get a little wet – I was used to that already so no big change

Design Goals

• Be as light as possible but have solid floor without flexing or bounce
• Reduce weight by using as little framing as possible (no big 2x4 frames)
  • I used 1x4’s (lighter, just as strong) to support plywood at middle lid
• Lids must not fall through – must be able to stand on lids without failure
  • I ripped 1x4’s to make a ledge for the lids to rest on
• Locking middle lid for secure storage
  • A locking Attwood latch for only $12-13
  • http://www.wolfsmarine.com/Attwood-99603B7-Latch-Kit-P4507.aspx
• Make a bait hanger for soft plastics
  • I used a display rod from Southern Imperial, cut it in half, welded fender washers on the ends as mounting plates, instant bait hanger!
    • http://www.southernimperial.com/merchandising-accessories-wand-retailers-c-214_215.html
• Secure deck extension to existing boat
  • I used only (4) ¼” stainless bolts – did not see the need to add more if bolted at extreme corners to resist curling

Material Used

• ¾” BC Pine plywood (flatter and not warped like CDX grade exterior plywood) – no it’s not marine grade either, keep reading J
• Cedar 2x4’s (lighter than pine)
• #2 grade 1x4 pine
• About (2) tubes of HD Liquid Nail (exterior grade, waterproof)
• About ¾ tube of 100% silicone
• Just over (1) cane of fiberglass resin (the cheap stuff….Bondex from Lowes)
  • I say it’s cheap because it’s $12-13 a can vs. top of the line West Marine system at about $150-200
  • Cheap stuff dries over several days – West Marine…..buddy you better get that stuff on in under 7mins before it hardens!
  • West Marine has 36,000lb modulus of elasticity – same as steel! (mod of elasticity means it takes 36,000 pounds to pull it apart basically)
• Lots of assorted stainless steel screws, lock nuts, & washers in various lengths (#6 for latches, #8’s for hinges, ¼”x3” bolts to secure new deck to original boat)
• Exterior grade deck screws for wood construction (small box)
• Pressure treated 2x4 (had some scrap material in my shed from previous projects)
• Thompson’s Waterseal for multiple materials (conc, masonry, wood, etc)

Lessons Learned:

• Don’t be a tightwad and save a few bucks on carpet or glue (see below)
  • Since I was making a deck extension, I replaced all carpet with a cheap outdoor carpet (microbial resistant meaning it’s marine grade) from Home Depot
  • Carpet did not have rubber backing and very thin. Saved some money but not that much – get decent material.
• DO NOT use outdoor carpet UNLESS it has a rubber backing
  • WHY?
  • Glad you asked……..adhesive will soak through carpet leaving footprints in the carpet and then re-harden gumming up the carpet with dried glue
• DO NOT use WATER BASED outdoor carpet adhesive
  • No matter what it says and no matter what online reviews say………it’s NOT waterproof and will get “mushy” when wet
  • If you do use carpet adhesive that is not “marine based”, read up and research it online vs. buying it in the store and seeing a $6 price tag and saying “HECK YEAH!” like I did. Impulse buy, totally regret it.
• 3M77 and Loctite Spray adhesives are good cheap alternatives for carpet replacement but, they are nowhere near as good as marine carpet adhesive
  • For a small project like this, it’s probably a good cheap alternative

Tips for a project such as this:

(I have to credit Fishinwrench here. He gave me a good tip (I have not done yet but will be soon)

• Install alum. sheet metal on the bottom of the lids to keep them from warping
  • Secure around the perimeter with screws at about 1-1/2-2” on center and a few in the middle of the panel as well
  • Apply a thin bead of 100% silicone around the edge between the alum. and the lid to keep water out. If you install it correctly, it should help control warping and keep the plywood in check.
  • The aluminum acts as a structural diaphragm when secured with screws and will limit the amount of stretch and prevent the ends from curling
  • If you don’t use screws, it’s pointless –the screws and sheet metal work in unison to lock down the plywood

Pics to follow in additional post to this thread.

[J-Doc]

Before Photos

Finished Project

***UPDATED 02/03/14***

A) Added photos of the initial voyage after the deck extension

I also dded photos showing alum. sheet metal backing for reinforcement to help prevent plywood warp during heated summer days and humidity.

I have to give credit to fishinwrench for the suggestion/idea. The sheet metal is fully secured to plywood creating a reinforcement diaphragm that should keep the plywood from curling. The sheet metal used is a bit smaller than the lids themselves which is a disadvantage. That's the only stock sizes I could get my hands on at the time. I'm hoping they work well enough. The idea is there nonetheless.

[J-Doc]

Construction Progress Photos

After cutting out initial deck and holes for the new lids

Reinforced hinge points with solid 2x4 material vs. plywood ends (much stronger connection)

Bottom view of project

View of project with sub-framing beneath. NOTE the ripped 2x4's are filler and not as much structural as much as they were needed to raise the deck up to be flush with the existing deck up front

Initial coat of epoxy resin to waterproof top layer

Photo showing ledge created to support deck lids - all fully epoxied and sealed with Liquid Nails prior to sealing with epoxy - I allowed 3/8" overlap to support the lids and secured the ripped 1x4 to the bottom with exterior deck screws about 3" on center as well as Liquid Nails to help secure it to the bottom of the plywood (overbuilt? - never coming off!)

These are the bait hangers after welding fender washers on the ends. I added a coat of brown epoxy paint.

Initial carpet installation

[Feathers and Fins]

Been watching it all the way through and enjoying it. HOWEVER there is still no power converter for the coffee maker and no blender for margaritas! And don't say you will just pull up to me for coffee your the coffee snob but I will make the margaritas.

[J-Doc]

Two words...

"Budget cuts!"

(Aka)

"the wife"

Okay that's 4 words. Lol

[fishinwrench]

You did a killer job, Jase!

[J-Doc]

Thanks.

I hope my thread inspires others to see a need and make a solution.

[J-Doc]

I'm happy to offer design help or advise too.

(I am a licensed architect, I think I can come up with a few ideas - haha)

[marcusearlt]

J-Doc, I'm diggin' the new deck, fantastic modification. Now you can fit the dog and all your baitcasters up there. However, those leather lounges looked super comfy and I bet it was hard to say goodbye to them. I am going to look in to that soft plastic storage technique you've shown us here for underneath the deck lids. I think that set up would work well on my bass boat. Thanks for sharing.

[J-Doc]

Thanks. I have to give credit to Legend Boats for the bait holders. Their Alpha series has them factory (better too).

Actually, I won't miss those seats at all. I didn't use them and the family rarely ventures out on the boat (claiming they will). They were rotting, vinyl was cracking, not enough storage, etc.

Oh and during this process I found an un-discovered place to store my rods when it's just me on the water (95% of the time). When replacing the carpet, I removed a board under the console to install the carpet and noticed a large gap that goes all the way up to the front of the boat.

Added some bungee chord, stainless tie downs and now I have rod storage. I can keep a few up front vs having 5-8 rods on an already small front deck.

I have a picture. I'll see if I can upload it from my phone.

I want to use some plastic gutter material (lighter than PVC) as rod tubes. That will come soon when it warms up in the spring.