Wheelhouse design/fabrication for 24' aluminum landing craft

Hello all;

I've been following this group for the last few years and this is my first post. I recently bought a 24' aluminum landing craft (see picture) which I'll be using primarily in Kodiak. I had contemplated building one but in the end decided to buy. I am however, intending to build a (fairly) small aluminum wheelhouse for it. It will be full width, tall enough to stand up in and probably 5 foot or so in length. I've been welding (mostly aluminum) as a hobby for the past 3 years and have a Miller mig welder. My questions concern more of the design and fabrication of the wheelhouse as opposed to the welding (of course I'll happily take any/all welding advise as well). So here goes:

1) what thickness aluminum would be recommended for the wheelhouse? The boat itself has 1/8" sides and 3/16" hull and deck. Pollard's Boat Building with Aluminum recommends 1/8" for a superstructure on a small boat. Thoughts?

2) How to stiffen the sides of the wheelhouse without taking up to much interior room and beef-up/support the roof so that it can withstand some load?

3) Build it on the boat itself or build it separate from the boat and attach it when complete. I don't have a garage/shop that the boat fits in though my garage would be plenty big to build the wheelhouse. Any advantage or disadvantage of one method over the other? One advantage, given that I live in Alaska, of building it off-boat is that I could work on it all winter long in the garage. Not to mention being able to turn it on its side/upside-down and do a bunch of horizontal welds as opposed to vertical and overhead.

4) There are plenty of picture of wheelhouses on landing craft on the net but I can't find any plans or layouts anywhere. I can certainly take a look at a few the next time I'm in Kodiak and wing it myself but I was wondering if any resources for designing/constructing one exist?

5) Pollard's Boat Building with Aluminum mentions tilting the sides panels of any superstructure inwards (tumblehome) to avoid an optical illusion that makes them appear to be sloping outboard. On a boat/cabin this size do I need to take this in to account?

6) Pollard also mentions welding superstructures to the framework below the decking for added strength. In my case the deck's already in place. I was thinking about, in addition to welding it to the deck/gunnels, bolting the side panels of the cabin to the vertical inside section of the formed gunnel. Thoughts?

I'm also debating whether or not the wheelhouse will go all the way to the splash-well or whether I'll leave a foot or two and put a rear door in the cabin. A trade off between valuable deck space forward versus easy access to the stern and outboards etc.

Thanks in advance.

David
Ester, Alaska

 

Just a couple of observations.

Keep that cabin as light in weight as possible.
Get the right kind of Aluminum. The alloys vary and some of them wont last long in Kodiak's weather.

Look at some of the other skiffs on Kodiak. See what kind of stiffeners they put into the cabin.
Aluminum tubing welded in for support is normal.
To stiffen the new cabin sides and cut down on the noise, make a 'wrinkler' of Hydraulic jacks and timbers or pay a sheet metal shop to do it, but get some 'Vee's' into that flat sheet metal.

Get 'googlesketch' and draw the whole thing out so you know what kind of room you'll have. Keep the balance of the whole thing in mind.

How are you going to get to the Bow? With a full width cabin you'll need something to walk on and hand rails up on the roof.

Plan on standard sized windows that can be replaced easily.

You'll need lots of Pumps, so keep those Batteries up high, away from the bilge.

If it were me, I'd leave a foot on either side of the Cabin for things like Antenna fold downs and boat hook storage and still have room to walk alongside the cabin.

Are you going to put some Floatation up under the gunn'ls? You'll need a Foot wide walk way to hold the Floatation and all your wiring and cables.

Are you going to have two big outboards?
One big I/O?
You'll need fuel storage. See the coasties about built in storage tanks. Lots of rules there.

Really, if your just hauling stuff to Ester from Kodiak, you just need a Bimini top with side curtains and a windshield.
That will work if your spending the night out fishing too.

 

DavidAK

I am considering buying a landing craft hull from ATEC. We just visited their plant in Kenai this morning. We are looking at a 26' hull with 10' cabin. The boat will be turnkey, as we have no shop to work on boats.
Was interested in any experiences you have had with ATEC, as well as any suggestions concerning the landing craft boats in general.
You are welcome to PM me if you wish.
SeaULater
Anchorage, AK

 

Atec?

A guy named HAMM was building some great hulls down in the Kenai area in the 70's and 80's.
He Built Bow-pickers, so he probably had a plane for a 'landing craft' as well.

I dont know ATEC.

The landing craft I went ashore in Korea (1958) was the only landing craft I've ever been on.
It let so much water in through those front doors, they had to build a floor up over the deck to keep us dry. The bilge pumps could not keep up with the amount of water coming in around the doors.

Keep that in mind when you look at the way his doors seal.
After you go up on the beach a time or two, those doors might distort a bit, and you may not get them to shut well enough to get back home.

Ask him about water jets for the bow. This is just my thoughts on getting a bow off the Muck on the other side of the inlet.
If you take on the Four Wheelers, and then try to back off the Muck, you may find the bow 'goooed' to the beach.

Especially if the Tide is receeding. You need plenty of power to back off that muck.
I always thought something like several jets of water pumped under the hull to keep that Muck from getting hold of the boat might help.

Twin engines instead of one big one.
You can move the stern from side to side with two engines which will help you get off the Muck.

Here's another Idea I had during a nightmare over on the west side.
You might drop two anchors 50' or so away from the landing site. Pay out the lines as you head into the Beach.
Then if you cant get the boat going backwards when you are loaded, those two anchors can be winched in to augment the main boat engines to get you off that Muck.

One more thought on Front loaders.
I would not want the water that came into the front deck to be able to wash back to the rear decks.
So you'd need two BIG pumps for the Front deck.
Heavily loaded you might take a lot of water over the bow as you head across the inlet. You dont want that water to was back and drownd your engine or your batteries.

Just my thoughts

 

Thanks for the input...

All info helps at this time. I also recieved a message from DavidAK and replyed to his personal email.