Mast setup, pls comment

Force = Mass x Acceleration

A sail or an aeroplane wing moves air. Measure the mass and acceleration of the air due to the sail or wing and you get the force.

The air "sees" multiple sails as one unit. The number of leading edges is one. A multiple sail rig has one leading edge and a number of slots. The slots allow the multiple elements to bend more wind and produce more force. The problem you will have is getting all the sails to trim correctly. The more sails/slots you have the angle that the boat can sail into the wind gets worse.

When you do not need/want maximum power, you still have all the drag of the slotted wing or multiple sails and lower performance.

 

Yes, but in the case of a bi-plane rig mentioned earlier?

 

Hi Jordan,

The weather (wind) plays a big role if you want to chase a big fish wheeling off to somewhere, meaning if there are high waves you cannot just charge to anywhere without risk of capsizing or burroughing the boat (you may actually see it when you go right through the wave, but you have to look quickly ) And yes, some fish really knows how to motor. He he... the guys I usually fish with used to laugh at my one big reel... now their thinking is changing slightly

On a motorboat you hook the fish, then if it makes for the other side of the world you have to try and follow it. The idea is not to ride on top of it which is mostly impossible, the idea is to give the angler a chance to turn the fish and to hopefully gain some line back. If you can turn the fish and fight it sideways it tires quicker than when it swims away from you, so you may not always follow after it, you may want to get an angle on it (sure you heard that one before) So if you're in a bay and the fish is going for shore you head on up the coast instead. Anyway, it happens quickly. (and forcefully). He he if you have the right line you can just hold on, the fish will tow the boat to somewhere, hope your arms doesn't stretch too much.

The cat (and tri's) has to be so you can move right around them. Of course there are compromises, if the fish moves around or under the boat you have to go around too. Unless you want to fight it back from under the boat

So if you are sailing (and saving the pile of money... piling up in your account of course ) and you do get a fish on, you have to get rid of the sails and go to the petrol motors... if it is a big fish and the right type. This you know really quickly. Mostly you can just cut the sails to stop and wait for the guy to get his fish out, but when the right fish goes on you must be able to keep the boat right for the guy fighting it. You shoud try to hold on to a rig that drags 120lb (50kg) trying to pull you off the boat and going in any direction. When someone grabs you from behind on the belt it's because you look a bit unstable there Mayday mayday mayday, Coast Guard we have a MOB traveling under water at about 80km/hr due North to Noth West, could you intercept please I repeat...

A-hand the-hen, if you're untidy with your line and it gets a loop around a finger it can get amputated very quickly... man are we having fun or what

 

When you're fishing bottoms you 'park' the boat, may even anchor if you're on the spot. Sails are furled. If you hook something big-ish you just run over everyone els to get to the other side... Sorrry... Sorrreeeee, sorreee.

Oh yes the masts and sails. I'm looking at the options. I have drawed the outline on the paving to size to get a feel for it... again... if I can get the wife to stop watering with sprayers and the customers parking on the boat

There is one thing though. I was recently involved in a prop design for a wind power generator.... there is a substantial difference in a design that makes wind ie aeroplane prop and the design for one that uses the wind. The earoplane prop hardly turns in wind blowing into it, the wind gen prop makes almost no thrust when you rev it up... I suspect it is going to be the same thing with sails. The sail that makes lift has to be shaped to fly with wind blowing at it.

I understand that there are a lot of variables during sailing, but the multiple 'half bra' (sorry, good shape though ) or semi-cone idea keeps coming back to me. If a sail consists of these and each vertical row has a correct angle which depends where in the sail it sits it may well be possible to make more power, for now the whole sail is full of leading edges, each with a vacuum behind it. The shape of each cone, being longer than the slit where it's wind passes through could also increase the sailing area... the vertical row laid flat could extend well beyond the sail height.

I haven't the funds to attempt it, so just speculation on logic... Imagine how dangerous some of us would be if we had a lot of money All those bra's to make a sail...

 

Birds wings does not have a smooth surface, how much does those fine turbulences help them to gain extra speed when like the Albatros they glide for days / months on end. Do those fine turbulences create a 'pocket' that gives extra speed and lift ?

 

Hey Fanie

I've never actually fished off a sailboat before so yea that would explain some of my stupid quotes. But yes I understand what you are saying about wearing down the fish. I've had a lot of experiances with being towed...its great fun seeing "true power" pulling a boat. I've also had the stern so far under water that the bottom of the fighting chair was under! And of course I've seen the bow under water. After I started replying to your post I have been very interested in sailboats for fishing.

Here is a design that might do you well. Seems to me this would be even better than a furling mast!
Hi/Low reefer reefer furling boom

Some photos of a Riviera that was in the tournament. The last photo is when they hooked a 70kg sail fish!

 

We might all be fishing from sailboats, if the cost of fuel continues to rise. Already, many charter boat captains have been driven out of the business, and a lot of private owners are cutting back. As an example, I have a friend with a 28 foot dual outboard who regularly goes out to blue water to fish. He burns 100 gallons of gas on a typical trip.

That said, big game fishing is a different matter, and if sailing becomes the only way to get to the fishing grounds, and there are no auxiliaries, then at a minimum, tackle will change. Now, big fish can be landed on lightweight gear, because the boats can pursue the fish whenever it takes too much line. If pure sailboats were to become the norm for fishing, then much heavier tackle would be required to land big fish.

I fish a lot from my little beachcruising cat Slider-- in fact, I rarely sail anywhere without a couple of lines out, and I'm rarely skunked. Here's a pic:



When we get a strike, we can go two ways. If it's a fish of moderate size, I just pinch up until we are going quite slowly, and let my crew land the fish. If it's a big fish, I generally heave to, and that's really the best way to handle it-- except that getting under way again once the fish is landed is a little more complicated than just bearing off.

If I were fishing for marlin, I'd need much heavier tackle than I'd need in a power boat.



Ray

http://slidercat.com

 

Furling booms... much better than furling masts.

 

Hi Ray,

You are right, switching to a sailing rig does present a couple of chalanges. The idea would be to have a couple of motors on it, hence the idea of getting rid of the sails and switch to motors. You then will burn only fuel when you have to. Getting there and back or when you trawl you sail. Should save considerable fuel.

Nice looking rig. You can leave the wife, but not the fishing rods

 

Too Late?

Fanie
I like you original bi-rig. I know I'm coming in late and you may have moved on. But I think the others have lead you far from your rig for your fishing boat.

Robs assumption that a spar is needed between the masts and parallelogram collapse is true only if you accept the rest of his design. I agree that stepping the mast at the center of the crossbeam requires the strongest beam. I also agree that there is high backstay tension in your design to keep jib sag within reasonable limits.

BUT, consider stepping the mast more forward. Since two sheets are already needed, one each side of the mast, to trim the sail, there is no reason to step it so far back. Stepping it to bisect the forestay/backstay angle will result in equal forces, not multiplied. This reduces the mast compression forces.

AND, consider stepping the mast on or near the INNER surface of the hull or a foot or two onto the beam . In this way the forestay/backstay act as to keep each mast head from moving inward, and the static tie between the mastheads keep them from moving outward. Since no sail is on the mast it does not have to be in the plane of the sails.

Others who claim that the sail area (CE) is too far forward or aft, have too little information to make that claim. It depends on where the keel or centerboard (CLR) is. And you may still be able to put it where you need it.
SO, consider moving the backstay to the aft cabin wall or crossbeam (and the mast step to the forward crossbeam). It makes the forestay more vertical and you give up some uplift, but you gain a clear aft deck for fishing. It’s your choice. Your foresail can still stretch aft as you show in the original sketch while trolling and travelling to and from the fishing grounds.
Larry Modes

 

Not in the least. I like the aft mast, there are a lot of advantages.

The main consideration having the masts so far aft is for mounting / demounting purposes, it means the mast foot will be sitting at about knee-hight instead of 2m up, it makes it very difficult to get the masts up there on top of the hulls.

The only obstruction to the fishing would be the two masts, I'm almost sure one can work around that.

Ideally I would prefer to have a neuclear engine in it and have no sails, power and hot water on demand. Indefenate propulsion.

 

http://www.fas.org/man/dod-101/sys/ship/eng/reactor.html

 

Fanie, have you seen the article titled "Economic Fishing Cat" in
http://www.voilesetvoiliers.com ? A new design by Gildas Plessis which I believe present some interesting similarities with your ideas.