• Welcome to the DeeperBlue.com Forums, the largest online community dedicated to Freediving, Scuba Diving and Spearfishing. To gain full access to the DeeperBlue.com Forums you must register for a free account. As a registered member you will be able to:

    • Join over 44,280+ fellow diving enthusiasts from around the world on this forum
    • Participate in and browse from over 516,210+ posts.
    • Communicate privately with other divers from around the world.
    • Post your own photos or view from 7,441+ user submitted images.
    • All this and much more...

    You can gain access to all this absolutely free when you register for an account, so sign up today!

Small boat setup.

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.


New Member
Feb 7, 2005
I purchased a smallish fiberglass tri-hull boat (15 feet/4.5 m) that needs to be gutted and re-floored. The hull is extremely stable due to its tri-hull sponson design. Since I must redo the interior anyway, I am wondering what I should keep in mind to set it up for spearfishing use (no SCUBA).

Any tips or ideas will be appreciated.

The boat is a foamed-floor non-sinker and due to its tri-hull design you can drag yourself into the boat from any angle without any risk of swamping, but it is an uncomfortable process because the gunnels are fairly high. Know of any smart ways to get in and out of the boat? It is too small for a transom dive platform and I think one of those fold-up transom ladders won't quite fit either.


Post pictures if you can.


How about a hook-over ladder?
I had one that was like a giant J upside down and 3 rungs the bottom rung had 2 legs that sat off the side of the hull so you could climb up.
It was made of aluminium so was really light and you could just throw it in the boat when you finished.
I am not sure if I still have it, to take pics of
hey oneoldude,

try a rope ladder with wooden or aluminium steps. easy practical and cheap. you could probably make one yourself. Then just fix some d-rings on your bullworks where you can attach one end then you just flic it over your capping rail so it dangles down into the water. easy
Thanks for the input guys.

Johnny - I tried a rope ladder years ago. If it extends below the bottom then it wraps under the boat when you start to climb. And if it is shorter, you can't get your feet on the rungs because the side of the hull is in the way. There must be a trick to it that I could not figure out. Suggestions?

Mark - Nice boat, but sometimes tough to work on. I am lucky. I live in an area where there are quite a few boat manufacturers. For example, Chris Crafts are made here and Donzi used to be less than two miles from me. So I have lots of sources for parts. Some home brew CC's are made from thin ply and laminated with glass then finished with Awlgrip. You can make it any way you like. In fact you can load the ply with mold release then rip it out the ply leaving only the glass. It is not too hard to do but the finishing is a pain if you want it to look beautiful.

Here is an example of a home brew CC. Not well finished though. But you can go as far as you like. http://70silverline.250free.com/Page3.html

See this for some ideas: http://www.cmmarineproducts.com/

Also check this out if you haven't seen it before: http://continuouswave.com/whaler/reference/

And this is a great resorce: http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=forum;f=26

Good luck and thanks all

Last edited:
Hi Oneoldude
Why not cut a door in the side or transom. If the deck is above the waterline and sealed then any leaks don't matter. If the deck isn't now, why not raise it and make your boat a self drainer - it's big enough. Recommended deck above loaded waterline is 10% of the beam. That shouldn't affect stability or seaworthyness unless you go silly (no tuna towers). Are you outboard powered? Single or twin? How big?
Got a good method of finishing the deck using gelcoat, micro baloons and a textured paint roller. Ive just finished a deck. Will post some pics tomorrow.
How about an insulated fish box or a wet fish tank?
Go for the door, it'll work.
Last edited:

I am planning to do most all you have suggested and leave out the tuna tower :D Where does the 10% rule come form? I was wondering how high I could go without instability.

I am putting in a CC that has a front seat that is an insulated live well and will probably put in a couple insulated boxes under the new deck areas.

I have two 'Rudes to choose from, an old 2 cyl 55 hp and a 3 cyl 70 hp. True prop hp should be about 85% of their ratings or about 47 and 60 respectively.

I have not thought about doors. The boat is a "bathtub" design and I fear it would be structurally weak if I cut through the "roll" on the gunnel. But it is a neat idea.

Here is what I am starting with: http://www.shareaproject.com/projectTut.php?p=10

Thanks for the input

Last edited:
10% is the standard Lloyds (of London) requirement and is used in all UK marine classifications eg DT passenger vessels, MCA charter vessels etc.
Cutting the gunnel for a door needs additional framing but is definitely possible, especially if the floor is raised thus reducing the size of the bulwalks.
Looked at your pics. Looks like what is known as a over reversed gull wing design rather than a tri-hederal. The side sponsons make it very quick as it rides on a cusion of air (like a cat), more so than a dory style and doesn't slam so much. Well that's the theory anyway.
I can post a few pics of doors but I must confess that they would be from larger boats. Most of our local crabbers now have doors not to get into the boat but to "shoot" the pots (traps) overboard without having to negotiate getting them over the gunnels. So same idea really.
Local dive boats, including my own, all have transom doors. I don't think that would suit you with your single large outboard.
Construction wise then "Strip the shit out of it" is definitely the best start. After that reducing the water/damp is the next priority. Plastic tents and dehumidifiers are a good bet.
Anyway best of luck, I'll see what pics I can find that might help.
oneoldude said:
Thanks for the input guys.

Johnny - I tried a rope ladder years ago. If it extends below the bottom then it wraps under the boat when you start to climb. And if it is shorter, you can't get your feet on the rungs because the side of the hull is in the way. There must be a trick to it that I could not figure out. Suggestions?

Yes, you have to fiddle a bit and strong arms help :martial . A good rope ladder has wide steps on them so you can get your feet on them, with 2 lines running down eachside of the step, meaning each step will have 4 holes in it with the rope running through and knots to stop them from moving. i wish i had a photo to show you, is there any old square rigger vessels around where you live? they for sure will have one. Also you could use modern materials such as teflon plastic for steps and braid on braid line ;) Another problem is you will probably scratch your topsides a bit ( if that matters). It is the cheapest option i can think of.
best of luck. :wave
Last edited:
Hi Oneoldude
Here's a few pics which might be of interest.
!. Small door and ladder on 5 metre outboard powered boat. Note how the transom above the waterline is inboard of the outboard well, creating a sort of mini swim platform inside of the hull. Neat idea.
2. Side door on vessel undergoing fit out. Note reinforcing and mega hinges.
3/4. Pictures of that deck finish I mentioned. Overview, with flush deck hatches. Close up of the edge of the hatches shows non slip "gel" finish. This deck is glass over ply. Looks good - no?
5. My own ali ladder. I know it's on a swim platform but you can make hook over gunwhale versions. My mates got one but couldn't find him so post that later. Marine grade ali (HE 30) is the material to use. It's srong, light and totaly corrosion resistant. You need TIG for welding though.
Again, best of luck
Hi 2 Oneoldude
Couldn't put this pic on previous so;
6. I started in small boats and traded up. I built my current 9m boat (Spearfish) using a commercial fishing boat hull. Do you like the name?

Couple of suggestions:

Have you tried getting into it from the water yet?? Remember, even though its a tri-hull, when you try and get into the boat, the boat WILL tilt into your direction, thereby lowering the gunnels, making it easier to get into. My old 4.3m Fibreglass cat did that.

What you could also try is to hang some ropes on the OUTSIDE of your gunnels. This would allow you to grab and pull yourself up.

Another thing worth looking at is outmounts. Build a fibreglass outmount box and mount your motor there-on. The outmount then acts as a dive platform as well as giving additional floation to your motor and boat. The downside is that your trailer would then most likely have to be extended (depending on how long your outmounts are)

Let us know how the project is getting along!!

two things we used to do in Qatar, when geting into the boat from the back by the engine (providing its off of course and it should be when divers are getting in or out) was to put my foot on that flat bit of metal that sticks out of the engine side just above the prop, this gives you enough height to get over the transom quite easily. Or sometimes we used a loop of rope with a small length of PVC (?) pipe for a step that when over the side, hangs a foot height (4 or 5 inches) below the transom, above the loop was a bit of thick foam rubber (to protect your ankle agaist the transom) and another loop of rope to pull yourself with; so you can grab the loop and put your foot in it and pull yourself up with the other, as your foot wants to disapear under the boat as you pull yourself, your ankle pushes against the transom stopping it from disapearing underneath (hence the foam). It used to work fine even with a waterski or wakebord on my foot so should be no problem with fins if your to idle to take them off :)
This guy will build anything you can conceive of:


I used to do a lot of diving from the Sea Lion (and the two previous Sea Lion iterations) when it was owned by George Hoffman. The mid-boat ladder shown is probably the nicest one I've used on a 32-foot boat. I am confident if you contact Enrique Alvarez with your requirements you will get a first-rate product. No affiliation, etc. and I haven't seen Enrique in years but still have one of his hammers from my wreck diving days.
Thanks for the feedback all!

Great pics. Wish I had the room to install some of those ideas.

Old Man Dave - Nice floor job. I assume you smooth finished first, taped the edges and then rolled on the non- slip. Looks like a professional job. Thanks for the Lloyds tip. And I hope the hull does float on air, my kidneys need all the help they can get.

Alison - I always toss the fins and gear onto the boat before boarding. Stepping on the anti-cavitation plate has been SOP for me. But it is a clumsy procedure. Also I have the same sliding-under-the-boat problem with rope ladders. You seem to have the solution. And it stowes easily. Do you have a pic?

Miles - I have not yet come in from the water on that boat. But I have leaned way out over the gunnels with my 220 pound body and they only dip a couple inches. The boat is a mini-barge in that respect. Very stable.

Johnny - Nope, no square rigged boats 'round heah. Now a combo of your idea and Alison's idea could be a winner.

Thanks all

Sorry, no pics, it was something an old boyfriend had on his skiboat back in the eighties, it worked very well though
How's that boat coming on?
Eventually got to try my new engine setup today. My current boat's finally running after a 2 year rebuild. 29ft LOA, 4.5/5 ton displacement, 370HP turbo diesel power, shaft drive. Made 24.5 knots flat out.
It's worth it in the end, although that day last Christmas, when I was working in the snow, I wasn't so sure.
PS The deisel's American. A Cummins.
Used to hop the cavitation plate in my youth, didn't lose to much blood either.

I drop a equipment line in the drink and use the aluminum ladder. Cheap easy to secure. It don't bash you when the water gets high. also if You forget to pull it, its just a light piece of plastic.

I do recommend the 4 rungs. just a little more comfortable.

btw. It's not uncommon to find them floating around as people do forget to secure them well.

Another side note: We had a kid killed here recently because someone forgot to pull an anchor and it hit him in the head. Freak accident but a good argument for a light ladder in a small boat.

Last edited: