Altering the floats/amas of an early Tremolino

[Corley]

I found the answer to my query on the Trem forum 8570 with the specs to the Brisbane Trem, and comments from the owner. Although a different strategy to mine, he has now proven his approach and understanding of loads has worked which, although different, is relatively easy to interpret for my coast cruising needs. Corley, you were on the money[Brisbane Trem], and good luck with your big Kurt Hughes project and small trem repairs . It was 5years ago but I should have remembered what sowed the seed.
The history on this forum is also full of treasures , thanks all, cheers

Do you have a link for that? I wouldn't mind having a look too even though I probably won't go down that path on my boat.

 

[trip the light fandango]

It's in the Tremolino Yahoo group, post number 8570. I attempted to read the lot years ago, problem solving, tuning and a comprehensive insight into all things Tremolino, very helpful members

 

[cavalier mk2]

Here is the small Nicol, immersed at rest amas work great for cruising. Different center of buoyancy at about 2/3rds aft compared to the central pivot motion of a Newick and a main hull designed to lift to the surface. It would get you a bit more payload as the amas carry their own weight, flatter sailing etc..... more drag in light conditions but not bad, My Vagabond is a great ghoster in slop which you wouldn't expect.

 

[trip the light fandango]

I've been enjoying learning a bit from following the interesting thread on these and the larger versions/cousins and really like them. They're a little more delicate as far as grounding/beaching than fibreglass [although they do have solid looking keels that protect the hull] and probably need more care/upkeep but they are just about everything I like in a sailing boat, ,near perfect...ha..and 25ft is the max I can fit on my mooring. The risk of pitchpoling seems very low[sailed within reason] with the main mass being aft of centre, such a clever design. They look like a something Erick Manners might approve of except that it is a bit of a hybrid, racer/cruiser and a bit short . They also look from above like they could have been made recently at least although there is more wing. This book I've been reading {safe multihull cruising] talks about the frustrations of how impossible it is to remove the commercial imperative from boat evaluation, that and the urge to overstate the positives of ones' own boat [ especially if one has altered it a bit...ha ]. Thank you for this useful bit of objective insight, immersed amas , centre of buoyancy, sailing characteristics,The lack of freeboard slows the Trem down a bit in slop. I once dropped a nylon washer from a fishing reel that sat on the water because of the surface tension, an original tremolino can sail at walking pace in those conditions, when everyone else is becalmed..amazing. regards .

 

[trip the light fandango]

The weight of a Hobie 18 is 181kgs,[H16,145kgs] the displacement of an early Tremolino is 431kgs, I'll be extending length of the Hobie 18 hulls by 600mm , the standard max free board is 700mm , I plan to increase it to closer to 1metre , with beams strong enough to take the additional stress. I think I'll need to keep the hobie 16 rocker, similar to early cruising trimarans, this should help keep the light helm the trem has. I expect to end up with a small tri that can manage more weather and chop, stay drier and higher than the original. I also expect a sense of stability/ comfort/safety that is reassuring . The new weight should be around 500kgs , I've already added about 30kgs increasing the freeboard on the central hull , I don't think there's any need to set up rudders on the amas/floats .
I have found that polyester resin in the thickness that beach cats are made of is a material that can be cut and remodelled relatively easily, sand back past the gel coat and lay woven matt being careful to work out the air bubbles, then Q cell as a filler, it means that I can recycle the still healthy bits of the old 16 ft[and others] hulls as donor parts and create something quickly ,cheaply and efficiently with some degree of the finish ready made,the joins need fairing. . This approach to the amas means I end up with a void between the hobie 18 hulls and new skin of about 200mm, may be a bit more depending on how they naturally fit together.

 

[BlueBell]

Voids are not good.
I'd look for a load solution on that one.

Otherwise, sounds like a good plan.
YeeeeeHaaaaaaa...

 

[trip the light fandango]

Ha ..yeehaa is right, hmm any cavity that can't be accessed visually or reached is suspicious you're right, I would run a tube to the lowest point in the new bilge so it can be drained though. On the main hull I used polyurethane foam and some layers of epoxy after the polyester glass, glassing in epoxy was ok but a little harder to finish as it cured, let alone sand, very time consuming, a lot of epoxy Q cell[ micro balloons], that's why I'm thinking a void, I expect water to find its way in there.Polyester is easy to use but just not as waterproof as epoxy or quite as tough.
If it looks like it isn't going to be able to support the load when beached or knocked, I'll be making little frame stations to brace {with holes for bilge flow. I think that the inherent strength of those curves will be pretty tough though, also I will run extra glass reinforcement down the spine,and maybe a replaceable timber strip or maybe delrin. I did want to avoid getting too bogged down in this project , keeping it quick and simple, it is already growing , ..extra weight is an anathema for a tri.. eek. Not sure what you mean by a load solution?
The beauty of having not started is that I could just sell the H18 I picked up for a real profit by properly repairing its holes and then be able to afford some fresher hobie 16s ,. not much yee haa in that though... ha.. cheers and thanks for the reply.

 

[BlueBell]

No, don't stop, carry-on.

Load Solution: analyze the loads created and how they are transmitted, look for the week link, where the break will happen and why.
Then, redesign and stiffen/strengthen that area effectively transferring that load on down the line, dissipating it as it fades.
Really, I'm an engineer.
PM me if this is too vague.

 

[trip the light fandango]

Ahah got it, I sourced a pair of hobie 16 front beams that will be attached with aluminium{I don't want to make fibreglass ones, my sons a welder] brackets that are located just forward and aft of the front and rear existing beams they will locate where the flange on a Trem meets the vertical following the form there., The rear new beams may have to be straight ally tube unfortunately. There will be corresponding braces across inside the main hull . These are the lifting strap areas . To explain the connection to the amas I'd have to show photos, I had a crack at explaining the structure on the scow bow thread here. It wasn't particularly successful.. ha . So yes I'm on to chasing the weakest point, it is fascinating,I want it to look graceful,..birdlike.. thats the aim anyway..ha .so here's a couple of photos ,the new beams would meet at the 3way joiner, with ally plates that use the existing bolts, creating some triangle shapes .,.. regards

 

[trip the light fandango]

The cormorants think its nice, but not quite as much as the cat, the added bulbs on the H16 were about the dopiest thing I did, it slowed her down a bit I think.., left over glass and foam can be a dangerous thing and another good reason to make the change. I'll be cutting the posts and new boots plus part of the H16 deck and bolting and glassing them on to the H18 decks, using 8inch inspection covers for access to glass in the bases. I re enforced them with thicker tube as a sleeve on the last treatment. H18 rely on the strength of the deck for rigidity, which I'll be adding to,...yeehaa ..that is going to be a fair bit of scrubbing, more reason to make and get the covers on, I'll tackle it on a rainy day, sheesh, I'll set the fishing lines up again to make it hard to land.

 

[trip the light fandango]

I saw some footage of Maserati on you tube , both her amas are in the water when she is at rest, it makes more sense than earlier Tri's with one ama always in the air.
The only disadvantage I can think of is the moment of capsize is going to be accelerated a little in the last few degrees because the sail wont release the wind quite as readily at that crucial point as the flying ama wont be quite as high to depower it. I shouldn't have put up that shot of the added bulb on the hobie ama, it is embarrassing, but I'll make something better, I write , rather lamely, because it's testament to an enthusiastic ignorance, a mistake, . ha,, I press on.
I'm beginning to think that making a carbon mast is a better and cheaper investment than an a better outboard that could go missing one night on the mooring.
The weight of my mast submerges the transom if I try to lower it on the water. If it weighed a 3rd less I could manage it far more easily myself, the boat would be a little more stable also, and a bit safer, cheers

 

[upchurchmr]

The disadvantage of both amas in the water is more drag sailing in light air conditions.
Most places have a significant percentage of time at light conditions

 

[trip the light fandango]

The most prominent wind here would be 12+ kn, on the edge of Bass straight being fed by the Southern ocean.
I consider myself a fair weather sailor, when it is pretty classic conditions is the most memorable for me,
but if I can't make the most of rough weather and enjoy it,
I'm in the wrong game .
Getting into little calm bays and sheltered points is what I most enjoy. It turns into a millpond about as often as it's 5to 10kn, not that often.
So extra drag in a small percentage of time drops down the list of compromises made owning this particular type of craft for mine . But a quiet motor would help, I am a little taken with the Dolphin inboard 12hp weighing in at 50kgs/110pounds, it means creating some through hull holes that don't really grab me, but at one litre per hour and a turbine humm it is a bit tempting . A carbon mast is probably a better way to go, still there's more pressing matters, like the bloody cormorants, regards

 

[trip the light fandango]

There are a couple of pitfalls involved in reading up on these forums, drifting off to sleep with design developments that keep piling up on the to do list. But to be fair I had issues before...already too far gone, it's fun
So after a winter reading of all things floating, the latest one that's got me is adding a sugar scoop around a metre long with a new mounting point for the rudder incorporated. At first I was thinking just alter a pulpit or push-pit as the frame which is a possibility, which I may to get the strength. I'm thinking of using the rudder system on the hobie 18 which look really nicely thought out ,considering the amas are going to be both immersed partly at anchor , so I may not need the centre rudder but it needs to be functional anyway for piece of mind.
Moving the mast back say 300ml is necessary and with the compression loads the mast base takes I'll be adding aluminium bolted to the flanges and shaped to fit the top of the coffin, err cabin(it's small). Combined with the other mods I'm making I think I'll take on one at a time.
I have 2 masts and I'll cut one down to take a standard the h16 sail to lower the weight highest up.
But stretching the centre hull and increasing the waterline length this mod may be the most comforting change when underway in a rough sea,... if it doesn't fall off., it won't. The stern on a Tremolino is small and triangular but I have changed it already, mine is about 150mm/6 inches deeper which was really hard to finish to an aesthetically pleasing state. So it would like some attention ,as does the bow, but that is an easier fix.
I haven't gone down the foiling path, that's a long way off...I think, but wow.

I've always admired the way a Chinese junk can absorb some impact from waves by diffusing water through the bow and stern , is in part the motivation, this scoop would play to that concept a little, adding some stability while keeping the bow up
I expect the scoop to have a volume of around 60 litres.
Looking at what I just wrote I think I'll save this project up for a while , collect parts and keep working on the theory while I complete the new amas and beam sections.

Fandango had enough water in one h16 amas that it stayed tilted that way for months, after draining and cleaning some cormorant poo off she now sits with the other ama in the water and the cormorants haven,t come back for 2 months, ..go figure, they're still on the cat nearby.
I bought a 1993 long leg 4hp twin.$300 I have been admiring these for quite awhile, got scammed, my own fault, I committed to the 4 hour round trip and it still may be ideal..with parts and work... $145 for a parts motor from a bloke who is more honest I think, should do it. Anyway I have gone down the light ,cheap and fairly quiet path. With another mount opposite I could run my 2.3hp and come out with a whopping 6.3hp using 2 litres per hr. and carry one as a back up on longer ventures. I need to find out whether I can fit a prop that will shunt better to get the bow around in strong headwinds,.. more forums..probably just a horsepower issue ,more wind ,more power to counter it.