Spear Fishing Boat Design

[Victor Bejan]

Hey guys I am a third year industrial design student from Melbourne Australia, I am currently working on a project for a concept 30ft sailing boat purposed for extended blue water diving trips. I have been spear fishing for the past 2 years in the bay and off of some back beaches as well. I have only ever done shore dives so I would greatly appreciate any feed back or ideas that any of you may have.
At the moment the ideas I have are to:
-Have a freezer running off of a generator on board for catch
-have an oversized shark shield that deploys out of the hull
-redesign the stern for easy water entry/exit
-include in built storage for gear I.e. guns, floats, rigging
-have a tv that is set up to live stream someone's go pro that is diving

If you see any problems with any of these ideas or you have an idea to add please let me know, thank you in advance

 

[Guffer]

Just a few thoughts from a fellow (amateur) boat builder:

- Shark Shield. Not sure how you will fit an oversized one in to a 30' hull without affecting the layout or hull shape considerably. You could maybe have a fold-down one lashed to the stern.
- Streaming Go Pro. The attenuation of the signal underwater could be tricky, especially from a small unit. Why not have a remote control underwater cam or even a small, cabled underwater RV?
- Large marine freezer = Energy hungry, even with a marine system. If you have the deck space why not solar-powered?

Additionally:
- Blue water V-Hull with bulb keel
- Semi-submerged bathing platform off the stern?
- Rigging with manual and/or electric winch for diver recovery (SWB, exhaustion, etc) or install a recovery sail similar as you would have for MOB drills.
- Raised pilot deck for spotting (although this will raise your boom, the Centre of force and pivot point of your rigging)
- You will need to think about shelter on deck (bimini, under boom tent, etc) for when you are not fishing
- You're going to need significant water tanks to rinse spearos/equipment post-dive as well as to live off of which as you use up is going to affect the balance of the boat. Either that or a desalination plant (which = power hungry) Both will take up space.
- A 30' sail boat is small and on the limit for blue-water sailing. 40' may solve some of the issues but this will significantly increase the cost.
- Does it need to be a sail boat? A power boat may be more forgiving in both hull shape and space available for things other than boaty stuff

I would be interested in following the project. Sounds interesting.

 

[Victor Bejan]

Thank you so much for your input I have taken it all on board, I have actually never been sailing so all of the advice you have offered is invaluable.
- What if the shark shield was attached to the keel?
- Solar powering is definitely a viable option at this stage that I will develop for the extra power consumption
- Is the reason you have recommended a bulb keel because it is shorter and allows closer access to reefs?
- I completely agree with you about the point on increasing the hull size and changing to being a power boat but unfortunately these two variables are fixed within our brief
- When you say raised pilot deck for spotting, is that spotting schools of fish? Is this not done by sonar? If that is the case would you recommend me making the boat a centre cock pit so that the pilot deck is raised? I understand from brief research that centre cockpits are not good for speed but that is not a primary concern.
- I will definitely post my final outcome on this blog

 

[landshark sa]

Due to manoeuvrability sail boats aren't great for spearfishing this may be remedied by adding an inflatable tender with small outboard - so you will have to cater for storage space. A compressor to inflate it will definitely be a nice to have.

With regards to fresh water, an option would be a atmospheric water generator - which is essentially a big dehumidifier. They can be set-up to run off solar.

 

[Victor Bejan]

landshark sa, thank you so much for your input.
when you say maneuverability are you referring to being able to get close to reefs due to keel restrictions? or are you referring to accurately maneuvering in deep water?
Using the tender to get to shallow reefs and as a base in the water is definitely something that I was considering so I am glad to hear that it the idea has potential.
The atmospheric water generator is something that I have not heard about before but is definitely an interesting solution that I will further research.
In regards to storing gear. Does anybody know if guns, wet suits and other dive equipment are generally stored on deck or are they meant to be stored inside due to the constant splashing of salt water which I can imagine would damage them?

 

[landshark sa]

I was referring more to general manoeuvring, turning to do another drift, pinpointing a reef or pinnacle, tracking spearos in the water, collecting fish that has been shot etc.

I don't know of international companies, but check out http://www.waterfromair.co.za/ which is a SA based company who manufactures these machines.

For a trip of a couple of days, as long as they are rinsed properly gear should be fine if stored above deck. I do however usually store my guns etc in purpose built PVC bags.

 

[Guffer]

The problem with storing stuff on the boat is that it is a salty environment, thus all the humidity in the air will carry some salt. Even if you hermatically seal a locker it will still have the salty moist air trapped inside. Most boats have a wet locker for foulies but these are open to the cabin to promote air circulation and prevent mould.

A landshark said, for a few days during a trip I would expect there to be little issue but I would not store the guns or a wetsuit on the boat.

As for location to store a gun, I like the racks you get just inboard and under the gunwhale, especially if there is a lip. Either that or you can sacrifice a single birth space for a gun and fin rack. If you have enough surplus power you could add an enclosure and add a little 10/20W heater element to keep the salty air dry thus negating the corrosion issue.

 

[cdavis]

A subject which I have thought a lot about. I take (and live on)a very small power boat into the Bahamas anywhere from 100 to 500 miles,every summer.

Principle 1: Its gotta be simple and bullet proof. Electrical equipment like freezers and shark shields are fine for trips of a week or two, but longer and you will see lots of failures. Don't depend on them. Storage for gear should be below deck or at least in very well secured boxes on the deck. Wet is ok by necessity. Any gear that is hurt by long term exposure to salt water is not going to hold up for the use you have in mind. For long trips, the simpler the spearing gear (and everything else) the better.

Principle 2: Its gotta be maneuverable. Shark is right. Spearing seriously on reefs off a sailboat requires a good dingy, preferably a high quality inflatable, fast enough to plane and tough enough for very hard use. Then you have to have a good place to store it aboard. Towing in big water is not an option. Hanging off the stern works if the boat is big enough to not be too badly affected by windage and you can get the inflatable high enough not to catch a big breaking following sea. Its a tricky trade off between an inflatable big enough to be effective and small enough to store.

 

[cdavis]

Ahh, I did not see the 30 ft requirement. In a sailboat, its just not practical, not maneuverable enough, not room for the dingy. Make it a power boat, low horse power, displacement hull and 30 ft is plenty. You don't really need a dingy, although one would be very handy and careful design could probably fit it in. Plenty of room otherwise. A correctly designed 30 ft power boat has as much or more room as a 36 ft sailboat.. When I get home I'll send a reference to "The Troller Yacht" a great design book for small trawlers.

 

[landshark sa]

The thing with spearos and offshore trips is the amount of kit that we take with. Also, with blue water hunting the kit is generally bigger and bulkier. It’s not just the standard gear you have to consider. Besides a wetsuit, weight-belt, fins etc. typically I'll take 4 guns - one of which is a big 4 band Tuna gun, big body board float, marker buoy, extra spears, service kits, spares(mask , snorkel etc) Now times that by 4 spearos and add in some fishing kit for good measure and you end up with a massive amount space required just for kit.

If the sail and 30ft length requirements are set in stone then the hull type may be variable?

Although I'm a mono-hull fan, a catamaran or trimaran will provide you with a A LOT more deck space.

 

[Victor Bejan]

I can see that there are going to be many difficulties to overcome here but perhaps there is a way to do it. Unfortunately the hull is fixed to being a Beneteau Oceanis 31. And it does have to be a sail boat, do you think that making the boat a centre cock pit thus raising the cock pit for spotting and also by my understanding slightly increasing the cabin space would be a good thing? Also if I make it a 3 berth with one single berth towards the bow with the galley just next to it and a two berth cabin towards the stern with a small saloon area leaving the aft space completely for a heated wet gear storage space (guns, wet suits etc), and then if I store a high quality dinghy with a a small outboard motor towards the rear of the boat and the boom can act as a winch when anchored to raise and lower it into the water?

 

[landshark sa]

Interestingly enough I spent about a week on on a 30ft Beneteau off Mauritius Island a few years ago and I now see why they gave you the yacht as your assignment.... It's going to be a one hell of a challenge to customise it to work as a proper spearfishing vessel!!

Although they are very seaworthy vessels it's really the last option I'd select, just too little space. In the photo below you can see we had to secure our surfboards to the starboard bow side as there is literally no other place for them:

In this case, an inflatable tender is a non-negotiable. We had a soft bottomed inflatable dingy that we used. Pictured in the photo as well as the little tiller arm outboard mounted on the stern of the yacht when not in use:

The inside quarters are cramped to say the least so I think you can forget about things such as water generators etc:

If you are going to a conceptual vessel then I think that you may consider some bells and whistles but if this should be anywhere close to a production design I'd say keep things as uncomplicated and uncluttered as possible.

 

[cdavis]

Is it allowable to use the hull, make it a power boat (diesel about 10-15 horse), design it with some"get home" sail ability, and get creative with the hull layout and storage?? You might get that to work and maybe without the dingy, even the inflatable is going to be seriously in the way while underway. Maybe flopper stoppers slung off a low light mast? That would hugely improve stability when either diving or doing crossings.

Part of the problem you face is the design constraints required for a decent sailboat work against making a decent dive boat. Try to hard to combine the two and you end up with an abortion that won't do anything well.

Some things to think about:

Assuming you are freediving, the best way to dive reefs is one guy driving the boat and the rest(two or more) in the water. 360 degree visibility and good maneuverability are critical .

If you go with an inflatable, having something that will carry the load you need and plane greatly increases your ability to dive. I had a 10 ft soft bottom inflatable with a 15 hp motor. It would plane 3 freedivers, gear, fish, etc. Even very good quality inflatables don't last very long under this kind of use.

The stern of most sailboats is a dangerous place for divers if the boat is jumping around a lot. If you have to go with no dingy and keep the sailboat design, pay attention to how the divers have to get into and out of the water. A sailboat design, ballasted, narrow, lots of weight(masts etc) above deck, will have a crazy motion with the sails down if you are trying to dive off it in heavy chop. Power boat designs are inherently better designs for this.

 

[Guffer]

One positve of a Bene hull is that you will have lots of space down below. The downside is that it will handle twice as bad as a bluewater sailing hull

 

[Victor Bejan]

Thank you all for your input, those photos were great, I haven't actually had a chance to get inside the boat so it is helpful to get an understanding of what it is currently like. I am definitely stuck with it being a Beneteau Oceanis 31 hull, I am able to change everything apart from the hull and that it needs to be primarily a sailing ship with an engine for navigating around marinas etc, not the other way around. I am currently thinking to ditch everything that is absolutely not necessary and focus primarily on two large heated lockers inside the ship. I will be doing this by having 2 bunk beds integrated into a communal area as apposed to private cabins. I will also make it a centre cockpit ship and attempt to accommodate a 10 ft dinghy with a 15 hp diesel engine (as per cdavis recommendations) that is stored permanently inflated on the aft deck. I will also consider including a pair of light flopper stoppers to make dive prep and exits/entries more pleasant in rough seas. What are your thoughts on this?

 

[Victor Bejan]

here are some rough sketches of the current interior/exterior please be critical

 

[cdavis]

A lot to think about.

How many divers do you plan for this boat to accommodate?

Its an interesting hull, looks like it is intended to be lightly loaded and plane under sail in higher winds. You will what to check its ability to carry the weight you are thinking about. Be careful not to so overload it that its a dog to sail. With that wide, relatively flat after body, its initial stability should be quite good, not a bad thing in a rocky anchorage or heavy chop. Warning: if you build the hull up too high or add too much weight, you might screw up the overall stability and end up with a dangerous boat.

Given you have settled on using a dingy, you won't be doing serious diving out of the Beneteau, so you won't need the flopper stoppers, especially on that hull.

Fold up dingys usually form a bundle the length of the dingys beam. I think you will need a different space than you illustrate if you decide to roll it up. Fold ups come with a flat bottom or an inflatable keel that creates a V bottom. The latter is a far better choice for your use. No significant difference in storage size.

Gear storage: Spearguns are long and the rest of the gear takes up a lot of space. That wide back deck would be a perfect place to build in some wet storage for dive gear.

Why the heated storage area?

A fresh water gear shower is wasted. Its wastes way too much water, you can't carry enough water nor should any diving gear need rinsing.

Are the vberth seats big enough for bunks? If so, you might dispense with one of the aft bunks and use the area for storage. Do you have space to raise one of the aft bunks and make a big gear storage under it? Might be another possibility.

A diesel 15 hp outboard, I'm not aware of. If its available, thats great, keeps your fuel needs much simpler. Careful of the weight and size of a diesel. If you are planning a gas outboard, try to incorporate fuel storage inside the boat. Jerry cans are a pain and the outboard will need a lot of fuel. On horse power, 10 horse is plenty if you can find a motor that will accommodate a large diameter power prop. That wasn't available when I was looking for mine, but might be now.

Thanks for letting us play with your ideas.

Connor

 

[Victor Bejan]

Sorry it has taken me so long to reply I have been swamped with work.
I am hoping that there will be enough gear for there to be 3 people in the water and have 4 people sleep on the boat.
What I understood based on the earlier posts is that wet suits and some of the diving gear must be cleaned with fresh water and stored in a space that is not exposed to salty air? Is this not true? especially on extended trips where you are not coming into port for up to a week? external storage could work quite well. I like your idea of the vberth seats becoming bunks, I think I will extend the length of the seating and turn it into a bunk section and turn one of the aft bunks into storage.

So you are think a 10hp inflatable with a V Bottom that runs on gas?

 

[landshark sa]

If you had unlimited space then having a dry chamber may be nice but considering the space constraints I wouldn't really worry about adding something like this.

You have to remember that the spearfishing kit is designed to operate in salt water / sea environment. I'll quite happily leave my kit above deck, preferably out of the sun, for a week long trip with a nice to have to be able to rinse it off with fresh water once in a while. I consider any kit that can't withstand this type of use as inferior and will most definitely not make into my kit bag.

 

[Diving Gecko]

Hey guys I am a third year industrial design student from Melbourne Australia, I am currently working on a project for a concept 30ft sailing boat purposed for extended blue water diving trips. I have been spear fishing for the past 2 years in the bay and off of some back beaches as well. I have only ever done shore dives so I would greatly appreciate any feed back or ideas that any of you may have.
At the moment the ideas I have are to:
-Have a freezer running off of a generator on board for catch
-have an oversized shark shield that deploys out of the hull
-redesign the stern for easy water entry/exit
-include in built storage for gear I.e. guns, floats, rigging
-have a tv that is set up to live stream someone's go pro that is diving

If you see any problems with any of these ideas or you have an idea to add please let me know, thank you in advance

I am a sailor turned spearo and love this idea

- I like the idea of the freezer. Add some solar and set aside a lot of space for proper insulation (solar is a tad hard to add to a boat with a lot of standing rigging but try. You get points for being green, too;-). If cost is no issue there are some pretty swank material which while thin, insulates amazingly well. Your regular blue foam would need 2-3 inches or so around all sides to do any good. Go to "cruisersforum.com", I think it is, and read up on this.

- Def go for easy exit and entry.

- A quick note on the gopro - the water kills your wifi streaming. You won't be able to do it. AFAIK it can't even stream to your wrist controller once submerged. Water is just too thick a medium.

- Fish gutting, rinsing, filetting station at the aft deck at proper table/working height. Slide carcass and guts back in the sea (or save for burley) and grab the saltwater hose for a quick rinse so only cleaned fish or filets go under deck. You could have custom baskets/containers that fit compartments of the freezer which could be used to carry fish from above to below deck.

- Fish finder on swing arm or somewhere easy to see.

- You def need a tender for picking up divers, not only marina use.

- Storage for guns as far aft as possible so that you don't have to carry gear over the deck. Ideally you put a "door" in the transom and grab your gun from in there. Would be cool if that room was accessible from above in the cockpit, too. Could stash as soon as you get your bum on the dive platform and then rinse from cockpit side later on with a fresh water hose.

- If the yacht is for colder climates, too then it could make sense to make the forepeak a "wet room". Like one big bathroom with hangers for wet gear. This way, after having exited the cold water, you walk up the foredeck and drop into the forepeak through the hatch, take a hot shower, hang your gear, grab a dry towel and walk into the boat DRY.

Speaking of dry, keep in mind that living on a wet and humid boat is no fun, so do what you can to make sure you don't have to go below in wet gear.