Crazy Idea?

So we've been given an old Seawing 24 tri. In fact, it's the original, hand made hull that was used as a plug to make the mold for the three or four others that were produced. This is what a Seawing is supposed to look like -




Mine looks like this -




The amas are not originals, at some point they were replaced with "production" amas.

It dates from 1976, a full fifty years ago! Thankfully, there is no wood, it's foam core. There still are some soft spots to dig out and fix. The decks are bad, it needs all new anti-skid and so forth. The nets are rotted away. There is no gel coat of course, that's also a good thing, I don't have to grind it all off. I do need to sand the hull and paint it.

Still has the original sails. The main is fully battened and reportedly she has something like 350 sq.ft. of sail set on what might be, or is supposed to be, a rotating wing mast.

Well, sails and rigging are a mess and ancient. Every last bit of hardware must be replaced. So, I'm thinking I'm gonna throw it all away and replace the rig with the wingsail from a Tiki 26. That's 285 sq. ft. of sail, and sounds more reasonable to me.

I'm also thinking of ripping out the huge daggerboard trunk in the middle of the forward cabin, and putting trunks in the amas, as per Tom Jones Hummingbird tri. Besides, I need the space for a bed!
I'll use a lighter plywood and fiberglass board, the one she has now is unbelievably heavy.

Also, as per the Jones Hummingbird, I'll be making cedar duckboards, instead of net tramps.
I know I need to watch the weight, but I want the side decks, not nets.

I need to add a boom to the Wingsail rig, so I reckon I'll also make one per the Jones Hummingbird. I have Toms books, and the Hummingbird plans are in them.

Otherwise, I'll be insulating the cabin with 1/4" closed cell foil backed insulation (I happily have a roll) and covering that with cedar slats. I've done this before, in our San Juan 21.




So, the interior finish and cabinetry, and I think the fiberglass repair should be straightforward enough....(Right?)

I'm a bit concerned about the new daggerboard trunks. I've made small ones for open boats...

Getting the balance of the new rig right is a bit of a concern.

I figure an old, free fiberglass boat is actually a pretty liberating kinda thing. I can't possibly make it any worse, it was gonna go to the dump if I didn't rescue it.

It needs a total rebuild anyway, so why not make it into a comfortable cruiser with a nice double bed in the forward cabin, and a rig easily handled by one old guy?

What could go wrong?

 

Welcome to the Forum Robert.

When I googled the Seawing 24, this interesting link came up -
The Seawing 24 Trimaran Lives https://smalltrimaran.co.uk/the-seawing-24-trimaran-lives/

And a ten year old thread on here about the pros and cons of the Tiki 26 rig -
Wharram's Mana's rig https://www.boatdesign.net/threads/wharrams-manas-rig.55375/

I think you would have to be very careful re the location of the main and the mizzen masts of the Tiki rig on the Seawing, while also taking into consideration the locations of the daggerboards in the amas - you are pretty much designing a new boat here.
I suppose one saving grace is that the mizzen can be used to help to balance the boat - but you still need to get the mast and daggerboard locations fairly accurate in the first place.

As always with any refit, keep an eagle eye on the weight of all the materials that come off the boat - and especially those that go on again. Little things add up quickly, even the weight of stuff like linings.

 

See if you can find some unbiased critiques on the wingsail before you commit, they are not the easiest to handle short handed from personal experience. The modern version of the Chinese rig is supposed to be easy solo, though I have not experienced them.
The Junk Rig Association - HOME https://www.junkrigassociation.org/

 

I would stick with the stick and look for a good set of sails from an F24 which should be pretty close.

How about some photos of the daggerboard case and interior?

I don’t see a slot from the top of the deck, is it not a full length case?

I believe the boat was designed for slide out wing bunks which should be easy to incorporate. You could even make a full width bunk if you wanted something wider. That way you wouldn’t need to remove the daggerboard case.

Having production floats is probably a good thing since the rest of the boat wasn’t really designed to be one.

How are the beam arms?

As you already know, weight and balance will be the biggest challenges.

 

On the one hand I completely agree re wingsails; also from personal experience.
On the other hand the "wingsail" from a Tiki 26 is a very different animal.
Gripping hand; listen to @SolGato.

 

Skip I'm talking the Wharram wingsail, two main halyards and a full length zippered pocket, then the traveller system, it is a handful to handle solo.

 

My bad, all my experience is with rigid wingsails, I've no experience with the Wharram wngsail and assumed the name was marketing hype.

 

The boat is in winter storage on the coast where I got it, I'll tow it home (some 300 miles) when the snow and ice melt off, and the mud dries out a bit. I live on a 40 acre off-grid homestead up in the mountains, up a few miles of old logging track.

So I can't provide photos yet. The daggerboard trunk is not full length. That's good, it doesn't support the deck! There is a hatch above it to remove the board from the cabin.
The beam arms and sockets appear to be in perfect condition.

The main cabin is, I think, six feet long. There are pretty good-sized wing alcoves, but at first glance I'd say they are rather small to actually sleep in, and they are not et up for it, no rail or lee cloth, you'd fall out for sure! A slide out bunk at that level would have maybe 18 inches "headroom"? That's a guess on my part at this point, but it looked less than two feet when I was in the cabin last, which was some months ago.
There is a narrow dinette setup in the cabin, and this can be converted to a rather narrow and somewhat short "double" bunk.

The forward compartment is taken up by the daggerboard trunk, and a porta potty. To make the boat into a comfortable cruiser for my wife and I, we simply must have a comfortable bed, one that does not need to be folded up into something else during the day.

My wife is a real trooper - We've spent 48 days living in a San Juan 21, anchored out every night, not once hitting a marina.
Cruising Small and Simple
She doesn't care about electricity, running water, refrigeration, or even head room, but she draws the line - A very solid, bold line at that - At a comfortable bed!

Putting the board trunk in the very best position in the whole durn boat for a nice berth was real stupid on the part of the designer, and tells me the boat was mostly intended as a play toy - just a day sailor, not at all a cruiser. It could have been put off-center, at the very least. The potty can slide under the cockpit, and be pulled out for use.

Putting daggerboard trunks in the amas is a little awkward, but should be easy enough to do. The fact that the Tom Jones Hummingbird tri was built that way encourages me. Shifting the board from one side to the other is the price to pay for the nice berth. Short tacking I'd not bother to shift the board, as Tom did in his tri.

Eh, there seems to be a bit of confusion - I did mean to use the Tiki 26 sloop rig, not the Mana cat-yawl rig, although the cat-yawl is my very favorite rig of all! I have a 15 foot cat-yawl that sails amazingly well.

Anyway, the balance of the rig is of course critical. An easy way to determine it would be to put the rig on the boat and sail it, using a temporary leeboard over the side of an ama to find the best fore and aft location for the foil. Seems straightforward enough.....

As far as keeping the original rig, I'm flat afraid of rotating wing masts and all that complication. The mast is so heavy I can't even move it myself, much less raise it. And at 350 sq. ft., I think the boat is over-canvased. Besides, every last wire, screw, turnbuckle and link is 50 years old, and the boat was sitting outside on a farm for years in the rain. I don't think there is a single piece of it that I'd trust.

Have others here re-used hardware and wire that old? How did it hold up?

I grant you that my San Jaun 21 is only a few years younger and is mostly all original, but it is less stressed, and was stored in a chicken coop (without chickens) for decades. All it's life in fact I think, save for it's first two years. So it's in pretty good shape.

I am interested in learning more from folks that have experience with the Wharram short-gaff sleeved rig. I rather fancied it would be easier to deal with than a slotted mast with bolt rope, as my San Juan 21 is rigged. I do think I'd need to fit a boom though.

I'm sure I'll have plenty of questions to ask of the more experience boat tinkerers here by and by!

 

The Seawing 24 was designed to be a lightweight performance Mutihull, not a comfortable cruiser.

If you want to redesign and customize it for more comfort and less performance go for it, but knocking the designer for not incorporating a large comfortable bed and instead placing the daggerboard in the most ideal spot for a big bed is well, pretty silly.

And let’s not forget, your boat as far as I know wasn’t really intended to be one.

Who knows what all was modified, added or changed over the years to try to build it out, and to what level that work was performed.

I certainly agree that everything should be gone over, even that it would be wise to de-power it given the age of the structure and the purpose for which it was built, but I don’t know if I’d be so quick to start making major changes to things like the daggerboard case, etc..

The original design being light and short is very sensitive, like any small performance boat, to changes in balance and weight placement.

The rotating rig is really no more complicated than a Hobie Beach Cat, but like any Mutihull in this size range, it does take a bit of effort to step and unstep.

 

But the designer claims otherwise in the opening sentence of your reprint above.

( "commodious" -roomy and comfortable )

 

For its size and performance, and it being a trailerable trimaran, it absolutely is.

However being commodious is typically secondary to the primary design goal of sail-ability when it comes to Multihulls in this class.

And a good part of sail-ability comes from the boards, not the beds.

 

You're addressing the wrong guy, I'm not the designer.

 

I am the owner of a Wharram with a 'wingsail' rig. My experience was not great. It may be less of an issue with the smaller mast of the T26, but I had problems with mine, especially lowering the rig. The sleeve would bind up on the mast and typically the sail would have to be physically hauled down. It also bound up several times. When trying to lower or reef in a sudden increase in wind, this created an issue.

I know I am in a minority, but I have altered my sails along the lines of the modifications made by another Wharram owner: Removing the sleeve, adding a luff rope and grommets, and going to a traditional lacing system.

It now works well for both raising and lowering the sails, requiring significantly less effort and they drop on their own, rather than having to be hauled down.

I only have a 5 or 600 miles under me with the new arrangement, but I can't say I can tell any difference in performance without the 'wing' sleeve.

All of which is to say that you might be better off keeping the existing rig and considering alternatives only if it doesn't work for you.

 

I’m addressing you because you made the point, based on a short description by the designer, that the designer claimed otherwise.

Just because the designer didn’t lead in with, or brag about performance and sail-ability doesn’t mean it wasn’t a focus of the design.

My point to the original poster is that daggerboard design, placement, structure strength, etc.. take precedence over accommodation in designs like this.

It’s not a monohull, and this particular vessel is essentially a prototype built to serve an entirely different purpose than a production boat.

 

No it wasn't.