Tremolino -mixing old with new

Discussion in 'Multihulls' started by SolGato, May 17, 2019.

  1. SolGato
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    SolGato Junior Member

    EBC96B19-7738-4202-9748-41A3716C5AA6.jpeg 1F039159-76BE-4DD9-8F02-84887E1730EB.gif

    I’ve always admired Newicks Tremolino design and got a chance to check one out in person a few months ago. It was a bit of a project and too much to take on at the time. I felt kinda bad passing on it as it deserved to be back on the water.

    One of the problems was that a few of the special cast aluminum interconnects were broken, but not to worry as I had a stash of old HobieCat parts that I convinced myself I could make work. And the other main issue was the Hobie 16 hulls needed a lot of work. I won’t even get into trailer condition.

    Anyway, in the end I decided that what the boat really needed and deserved was an updating and redesign of the frame and outer hulls. I was thinking a set of new plastic Hobie hulls would work well since one of the weaknesses of the original design is the heavy small volume hulls. The new plastic hulls are not only light, but also have a tremendous amount of volume. Old Hobie16 hulls are now in their prime around these parts due to UV and tropical climate, so most need a lot of work and in the end you still have a pretty heavy low volume hull.

    Flash forward to today where I find myself thinking about that poor Tremolino, but only because I bought a Hobie Wave a month ago and it has the hulls I was imagining might work well with the Tremolino.

    So here are some of the concerns I have to think through before possibly pursuing a Tremolino project:

    1. The original Tremolino design was 23.5’L with a 16.5” beam using Hobie16 hulls for the Amas at 16.5’L, whereas the plastic Hobie Wave hulls are 13’L. The plastic hulls are not only shorter, but they also have more freeboard and volume, so the aka frame geometry would need redesigning and there are still questions about compatibility of the hulls regarding their length and volume and mounting points.

    2. Regarding the aka frame redesign, the original design used the Hobie style frame with corners and interconnects that attach to posts coming out of the hulls. The fore beam has a big curve in in similar to the curve in a classic HobieCat, while the rear beam is straight with the two mounted at different heights.

    So taking into account the design details above and comparing the original design of the Tremolino and its use of production Hobie16 hulls, I’m wondering if it would be possible to adapt the newer hulls to the Tremolino by constructing a new aka system comprised of two beams made of mast extrusion in similar fashion to new construction techniques used on beach cats. Basically instead of using a curved front beam and using posts, using straight beams that pass through the Amas.

    My concern is how important the curve was in Newicks design, if it was due to compression and supporting the mast, if it was a necessary design to keep things simple and external while making use of a production hull with its own attaching system, or was it to allow for easy access to the cabin, or a way to simply make a long undersized beam stronger, etc..

    There are a lot of Trimarans out there that use two straight beams, and most modern beach cats use a straight beam thru hull system, although I’ve noticed many are using a more substantial extrusion than what was used back in the day. Maybe his design was just based on the technology and availability of parts and materials at the time? I don’t really know...

    Anyway, I find myself thinking about the poor old Tremolino again because I have a few Hobie masts which could be used for new beams and now have this Hobie Wave with modern donor hulls, so I’m one again considering the project as I’m worried it might fall into further disrepair and feel it is worth rescuing.
     
    Last edited: May 17, 2019
  2. trip the light fandango
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    trip the light fandango Senior Member

    Well as a Tremolino owner I would say it is definitely worth saving, mine is fibreglass , heavier and therefore not quite the classic that the plywood original is, but mine is bullet proof and lovely to sail still. The problem is that nearly every modification ever done to an original trem is more volume/longer amas/floats .. There is a forum dedicated to the Temolino ,Tremolino Yahoo group
    There's one on facebook I haven't visited, they will both be very helpful and knowledgeable and can really answer your question. with some care you can bend a mast to suit I think,, [I have with 14ft cat mast for the bimini].. what is strong enough and a similar curve locally.?. the curves add to the look significantly.
    It will be suggested that you make both amas and beams from ply I reckon, but that isn't what you asked about. They can be a wet boat in over 1metre chop but they are a design classic and proof of Newicks understanding of sailing. Castings are easy using a fibreglass lay up. Unfortunately I think your wave donor hulls are just a bit short, so I'm not sure , cheers
     
  3. SolGato
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    SolGato Junior Member

    Thanks @trip the light fandango . This particular Tremolino is a production version as well so it has the fiberglass center hull which is really the best part condition-wise of all the components.

    The issue with the beams is that on newer hulls like the Hobie hulls, the beams pass through to connect and join them versus laying across the top and clamping or lashing down like some designs, which would be easy to adapt by glassing in an angled perch block. But passing through the hull poses a problem for the fore curved beam since it would not be entering at a perpendicular angle. Perhaps a curve could be bent, and then at the ends straightened out again so as to become parallel to the water for the short section that need to slip through the hull. I believe the beam extrusions on the Wave are a bit more robust than the original Tremolino beams, so overall they should be stronger.

    My main reason for proposing the modification is because I already have the parts and materials, and because the Tremolino already has a reputation of being a bit nose heavy and could probably benefit from lighter larger volume hulls, especially in our swelly waters.

    I too am concerned the Wave hulls might be too short, but I’m not an expert as to how length and volume in relation to the main hull and positioning of the Amas fore and aft come into play on a sailboat of its size.

    And I agree any boat as cool as a Tremolino definitely deserves to be saved!
     
    Last edited: May 17, 2019
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  4. SolGato
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    SolGato Junior Member

    Here one photo I found doing a general search that was posted on a thread about Tremolinos. It’s a more modern take on the design but does use Amas with straight beams that pass through the hull.

    I couldn’t find any info about using shorter hulls like H14, or the newer plastic Hobie hulls. I’m thinking nobody has adapted the plastic hulls because they are expensive and most boats of plastic construction are still in use.

    Of course, one could also consider using a pair of Hobie Getaway hulls which use the same straight beam thru hull setup but measure 16’7” in length which is about the same as the original H16 hulls, but have far more freeboard and volume.

    For reference, a new Hobie Getaway has a capacity of 1000lbs and the Wave 650lbs, so their hulls are extremely buoyant while being lightweight. Certainly a lot different than the classic H16 and H14 hulls.

    My first solar electric conversion used a H14 and people thought the boat was sinking, but that’s how H14 sit in the water and probably partly why the classic Hobies use the post to tramp frame system to create freeboard when at rest.

    Anyway if anyone cares to address the issue of using shorter but more buoyant hulls with the long center hull that has a background in boat design, I’m all ears. I figure there has to be a relationship between the two. Certainly Hobie 16 hulls don’t do a lot of work at their bows to keep the boat afloat since they have little volume and such an aggressive rocker. Most of the photos I’ve seen of the boats under sail show a good amount of the bow of the hulls out of the water with the rocker doing most of the work. They look almost more as training wheels with the Tremolino. The newer Hobie hulls don’t have much rocker to them at all which would probably cause more wetted surface in the water and likely a slower but more stable boat? The other issue is the plastic hulls taper to the stern with a built in keel that runs 3/4 the length of the hull. Not sure how that would affect performance either.

    84093E82-A4A2-43A6-8F68-57112D7BF61F.jpeg

    Just thinking out loud here as I’m no expert.
     
  5. trip the light fandango
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    trip the light fandango Senior Member

    Humdinger looks like it's showing the way, except it isn't a fibreglass production job, but still.
    I can't help you with the the figures as to whether the conversion can work, all I can do is offer a few ideas which may or may not be practical.
    It looks like you could step down to the Hobie wave through hull beam section by having one or two short mast sections on top of each other. However the volume of the wave hulls do need to be similar or more than a hobie 16 I think, although if you make the beams wider than stock there may be a play off that makes the boat a little less versatile in range of conditions but still a lot of fun/fast. Anyway the experts should be able to give a fairly definitive answer because most of the specs are available, you may have to assemble them to make it easier for them to make the equations. Solid bracing struts/water stays that reach the stub mast/ original wave beams that go through the outer hulls could be a strategy. Just thinking out loud too. cheers
     
  6. W17 designer
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    W17 designer Senior Member

    SolGato: "Anyway if anyone cares to address the issue of using shorter but more buoyant hulls with the long center hull that has a background in boat design, I’m all ears. I figure there has to be a relationship between the two. Certainly Hobie 16 hulls don’t do a lot of work at their bows to keep the boat afloat since they have little volume and such an aggressive rocker. Most of the photos I’ve seen of the boats under sail show a good amount of the bow of the hulls out of the water with the rocker doing most of the work. They look almost more as training wheels with the Tremolino. The newer Hobie hulls don’t have much rocker to them at all which would probably cause more wetted surface in the water and likely a slower but more stable boat? "

    Perhaps I can shed some light on this ... (just ran into your Thread by accident but see its current)
    The reference to 'training wheels' for a short ama with rocker (like a Hobie hull) is rather appropriate, but is that what you want?
    THE AMA STORY
    There are several factors that should guide the ideal ama shape.
    When sailing, that leeward ama is pushed down and just as for the main hull, the longer its waterline, the faster and more efficient it will be. There are now racing tri's with all 3 hulls the same length and some with the amas even as much as a foot longer at the bow (than the main hull), as this adds important diagonal stability to reduce the risk of pitchpoling. High keel rocker is also highly limiting for speed, causing added resistance at both ends of the hull. So that's another issue with Hobie hulls for amas.
    Then, to help control pitching and resist nose diving, you want the buoyancy significantly forward of where it is in the main hull. This means having a fairly deep bow but with the stern slightly lifting so that it's the last part to go under. Even if not the very latest design, look at your Humdinger photo as it is showing the way of the future. (A look at my W22 ama (see below) also shows I follow what I'm preaching here ;-)
    Two other very important factors are the volume and the overall beam (aka length). The more there is of both, the more sail you can support and the higher your potential speed. But, you can go too far. Not only will the loads in the beams be significantly increased, but if you make the transverse stability TOO high, then when pressed hard in a gust, you have increased the risk of pitch-poling as "something has to give" .. and now, pitching poling becomes easier than capsizing! But for sure, short amas with high rocker will not be the fastest or most efficient solution. Such a use of Hobie-type hulls is ONLY because they are cheaply available, not because they work the best. Most cat hulls have far too little buoyancy for a fast trimaran. And if you are wondering why Dick Newick ever used them, it's for the same reason .., they were available and inexpensive and he also replaced them later, by longer designs with more buoyancy even for his own Tremolino's. (One often forgotten fact is that as an ama is pressed down into the water, its buoyancy replaces buoyancy of the main hull, which then starts to lift out by the same amount of volume. So one shape replaces the other).

    But low buoyancy amas HAVE been used on production boats sold for multihull beginners .. and the Astus 14 (from France) is just one example. They even advertised it as 'a skiff with training wheels'. The advantage in this case was that the amas were small enough to be pushed under water (just 80L volume) so that the boat would heel more like a mono that the sailor was used to; and as it could/would capsize, this would also make it easier to right again. But sailors soon realized this gave up potential speed and the larger, newer Astus models all have almost full length amas of more volume ... and the trend today is 'more and more volume' to sail flatter and faster, with capsizes more frequently ending up as pitchpoles ... until skippers learn that reducing sail early is the best solution .. something I promote frequently via my website.
    Another factor I will mention is the stern of the amas. What shape should that be?
    It's here that designers tend to go their own ways. For a boat sailed often downwind, amas with enough forward buoyancy to prevent nose diving, can be faster if they have a full ama stern to quasi-plane on. Designer Kurt Hughes is a fan of this approach. However, for going upwind when an ama can be pressed well under, an ama with a more fishtail shape will have less resistance .. and both Chris White and John Shuttleworth are advocates for this design. Personally, I agree with John (perhaps because we studied at the same place ..haha, but also seen supporting tank tests), but my own designs are a compromise of these extremes for more practical reasons ... attachment width required for the rear aka on the w17, and to have a transom to attach a rudder to, on the W22/W32. Two other disadvantages of the fuller stern, is that when its really pushed down, it not only creates a lot of added resistance compared to the fishtail stern, but it also lifts the stern of the main hull ... sometimes causing the main rudder to lift out enough to cavitate! I had exactly this experience as my Magic Hempel once had its amas replaced by a design from Kurt, but when she reached 20kts (which was nearly once a month), the rudder started to cavitate and I was never able to exceed 22kts and only with zero steering control over 20. With her original slimmer stern amas however, she had been timed at 25.4k when new and she now (I understand) once again has new amas.
    One final factor I will raise here, is that the ama can be put to good use for a couple of other reasons. One is as a support for foils if that is the route your design is to take. In this case, one might justify a shorter, smaller hull with less weight and windage, as it will hopefully ride above the water and only really needed for static buoyancy. But the other reason is with an improved asymmetrical shape to lower leeway. This is something I have experimented with quite a bit and the resulting ama shape I've developed for my W17 is unique ... as is the very low leeway of the boat. So much so that I'm using almost identical hulls for a new, larger boat under development. (Check previously published articles about the W17 for more on this if interested).
    Despite all that is here, I've not even mentioned the cross section of an ama ... but that's another study on its own. I will simply confirm that, as for the main hull, at both very high and very low speeds, wetted surface is critical and the lowest is achieved with semi-circular shapes. However, in the extended middle speed range where wave-making is typically the most critical, other shapes even with chines and more vertical sides can be surprisingly efficient and effective, and also at lower cost with less build time. For me personally (as for the main hull), a full 'Vee'd section is perhaps the worst choice for the leeward ama, as such hulls 'pump' surface water horizontally as they interface with waves, creating added resistance and spray, as well as having the highest wetted surface, but a small vee or narrow bottom is needed for the upper windward side, to interface gently with passing waves, requiring a compromise of shapes to work well on both sides ... see my 2018 PBB article for more on this.
    Also more under Design Issues at www.smalltridesign.com

    W22-profile.jpg

    ADDED: May 19th, 2019
    PS: I think it's worth adding this. The design of catamaran hulls and trimaran amas is NOT the same and using cat hulls will generally be a compromise. It can work fine, but one has to match the needs very carefully for success.
    So what are the main differences in design ?
    With a cat, one often has two hulls in the water offering buoyancy and lift, so they can have their center of buoyancy slightly farther aft than that required for a trimaran ama that are each pushed down alone. Also, the trimaran ama can be designed to be slightly asymmetrical to advantage, as only one is in the water at the same time .. so it's somewhat like having a gybing centerboard on a boat, as each can be shaped and angled to negate leeway on one particular side.
    The buoyancy required is also typically greater for the ama, as on a catamaran, two hulls share the total load. Also, an ama can be pushed farther underwater than a cat hull ever is, so changing its shape requirements and finally, when the ama is on the windward side and flying above the water, a bulbous or flat bottom shape can create annoying noise as wave tops hit it ...whereas if correctly designed AS an ama, this noise and resistance can be better negated. So cat hulls on trimarans, really are a compromise.
    mike at: www.smalltridesign.com
     
    Last edited: May 19, 2019
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  7. trip the light fandango
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    trip the light fandango Senior Member

    If you can find some hobie 16 amas in good condition they are worth the effort, even if you have to make new castings out of fibreglass. I'm guessing that you can't get resin where you are because no one will deliver it for a reasonable price. The beauty of the H16 hulls is that they submerge when you've over cooked it, slow the boat to a stop, and then your on your merry way again, pitchpoling doesn't feel likely at all, neither does any capsize.If it is going to gust over 18 to 20 knots+ you do need to reef [at least for my H18 mast sail experience]. The rocker in the H16 hulls seem to give the Trem some grace in rough weather. Setting them inside out as W17 has talked about the advantages of the flat being centre hull side may actually improve the overall speed,, I don't know, but I suspect he's right, also considering his depth of experience The good intentions of John Olin and Dick Newicks' design criteria shine through and set it up as an everymans ,womans,weekend design classic. Setting the wave hulls slightly forward to make up for the shortness may help but it adds weight forward also..? Swell should be ok, it's more metre + chop that makes the boat wet.
    This time W17 I'm sticking to my experience as you suggested, I own one, you seem to be concerned with outright speed, winning,. fast is more fun was a Tremolino criteria, so you are in the ballpark but not quite in the game this craft was very cleverly set up in the 70s and it still stands, I'm beginning to think I am a sore loser..Ha ,regards
     
    Last edited: May 19, 2019
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  8. W17 designer
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    W17 designer Senior Member

    TLLF: I respect your view Stuart, but using H16 hulls is a compromise ... more towards the early Astus design (and reversing them without toe-in, may well not work). No argument with the fact that a H16 hull enters wave tops gently when falling vertically ... but when a boat is designed to go forward with the best efficiency, longer less-rockered amas do make a significant improvement. 'Winning' is not a factor for me as I seldom race anymore .... but I am still energized by 'efficiency'.
    And as I pointed out, Dick Newick also agreed about the compromise and moved away from Hobie hulls with longer, less rockered amas for his later Tremolino, so why push old tech? I know there must be other readers out there who have tried and compared the two shapes, so perhaps they will respond. Either way, enjoy what you are doing, it's still fun to learn and try new things, even at my vintage ;)

    Here is a converted Trem that might interest you. There must be dozens ... check out the Tremolino owners trimaran group
    Tremolino trimaran group https://www.facebook.com/pg/Newicktremolinogroup/photos/?tab=album&album_id=1588618501442623

    Also: 12 years ago, a post on line said this:
    “If you want the dirt on the Tremolino, call Dick Newick. He designed it and has a wealth of information and ideas on how to improve things. His new version has a plumb bow and is rounder in sections going aft. His ama's are better than the H-16's and his aka's unchanged. I talked to him a couple of years ago about the situation and he was very forthright”.

    BTW: I have sailed both the H-16 and a Tremolino. The experience in both cases was that BOTH boats are unnecessarily 'nervous & wet' ... the W17 is WAY drier and more relaxed at the same speed, and so was my Dragonfly. Most early small tris were 'nervous & wet' though ... including the Buccaneer 24's I had .. mostly due to the dated Vee'd hulls I figured.
     
    Last edited: May 19, 2019
  9. Trogolo
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    Trogolo New Member

    I don't think the curve is at all necessary.

    Richard Woods has designed a similar but shorter 18ft boat, and he uses 16 foot amas. Interestingly he recommends anything but the Hobie 16 amas. With this in mind, as well as the dissatisfaction with the H16 amas among Tremolino owners, I don't think you should be using the H16 as a reference for the new amas.

    Sailing Catamarans - Strike 18 trimaran using a 16ft beach cat for hulls and rig http://sailingcatamarans.com/index.php/designs/27-trimarans-under-25/168-strike-18-55m-trimaran-using-a-16ft-beach-cat-for-hulls-and-rig-p100-mainhull-only-or-p150-including-quattro-16-plans
     
  10. W17 designer
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    W17 designer Senior Member

    Yes, Richard and I are often 'on the same page' re design aspects. We've enjoyed to sit and chat about it in fact. ;-)
    His Strike 18 is a slightly larger and different purpose boat to my W17, but the boats share similar main hulls and overall dryness ... and both will out-sail the Windrider 17 and be a lot drier and more comfortable doing so.
    The Strike 18 offers cuddy rain protection (neither boat makes spray) and uses recycled existing parts (for sails, amas and cost saving) while the W17 has a more sophisticated rig with a rotating wing-mast, cleaner internal structure, custom designed amas for reduced leeway and a self-draining cockpit. With a lot of mutual respect, I know Richard would enjoy the W17 - something he once told me himself. We both still love sailing small boats .... both new and vintage. . Go Richard !

    In case you missed it, I added a PS to the AMA STORY posted May 18th above, that now covers the different design requirements of a catamaran hull and a trimaran ama. .Thought it best to keep it all together ;-)
     
    Last edited: May 19, 2019
  11. trip the light fandango
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    trip the light fandango Senior Member

    Fair enough Mike, I didn't know you had sailed one, I simply don't have the experience to say comparatively what is a "nervous " boat, particularly to someone with your experience, my point was that because the H16 hulls make the Trem less powerful it is forgiving, I think I'll quietly hop back in my box, ha . regards
    Edit, back out of the box, all those times I've left the helm and just watched the boat do its thing, nervous,..not in any way
     
    Last edited: May 20, 2019
  12. SolGato
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    SolGato Junior Member

    Thanks you all for your contributions especially @W17 designer. That’s a treasure trove of info, a lot of which makes sense if you have studied the design characteristics of boats that are known to be good performers.

    My thought about the possibility of the lack of overall length being somewhat offset by the larger volume of the plastic hulls seems be somewhat inline with some of W17’s comments.

    As I mentioned, a lot of the photos I’ve come across of the Tremolino under sail suggest that the front of the hulls don’t provide much buoyancy as they are out of the water with the rocker of the hull doing most of the work. Now that’s not to say that when the boat is pushed hard and starts to pitch that they don’t help to keep the boat righted, but I wonder just how important the first foot and a half or so is especially since it doesn’t have much volume and is quite heavy considering the lack of volume. Again, part of this might all have to do with using an existing production hull which already had predetermined mounting points.

    So then, let’s say the overall length of the plastic Hobie hulls wasn’t an issue. The next issue as W17 points out is where the volume is in the hull because having more volume up front is important to keep the bow up and since the Tremolino already has a reputation for being nose heavy, it would be important to make sure you have a good amount of volume up front especially if the ama is going to be shorter. Since the Hobie Wave is a shorter boat without a foreword trampoline, the hulls are not as bulgy as the Getaway. The wave hulls do however share the same overall shape and profile. Attached for reference is a photo of the shape and profile of the bottom of Hobie Wave hulls. As you can see after the knife edge profile the hulls quickly taper out to offer a lot volume.

    One of my concerns still relates to the built in keel fin and how it would affect performance. They are obviously designed to help keep a HobieCat on point when flying a hull since the new boats don’t use a dagger board, while also providing a reinforced hull bottom for beaching and protection from reef strikes since it is a plastic boat I would presume.

    How do you guys think this feature would affect performance if the hulls were used on a Trimaran?

    Regarding W17’s comments about catamaran hull designs being less ideal for Trimaran use due to the job they are tasked with with regard to their shape and volume characteristics, I think aside from the built in keel fin discussed above, the plastic hulls have a lot of the right features for Trimaran use like volume up front, tapering in back, and a lack of rocker.

    Lastly, can anyone comment on the original designs use of a fore curved beam? I know it’s become a bit of a signature Newick design, but how important do you guys think it is for supporting the Amas on a boat this size?

    In my mind, I would think switching to two straight beams that pass through the Amas like Humdinger and using stronger mast extrusions than the original design used would be more than adequate to handle the loads, especially since it seems one of the other major weaknesses of the original design was the cast aluminum interconnect fittings and the flimsy frame. I’m thinking that by introducing the compound curve into the foreword beam, Newick was able to create a strong structure that kept the hulls square with one another since the rear beam is straight because without that curve and/or the tension of a trampoline, even a classic Hobie Cat becomes pretty flimsy. This is probably something Hobie learned early on since as it was a feature of the H14. Since the Tremolino’s frame spans even wider and doesn’t use a trampoline to keep it all together, it becomes an even more important design feature of the Tremolino and one that was likely borrowed from the HobieCat since it was proven and the Tremolino uses the H16 hulls.

    I’m still digesting and processing all the info posted, but a lot of it seems encouraging and fits with how things are interrelated in my mind with regard to performance and stability.

    The Hobie Getaway hulls definitely have the right lengths and would seem to be a better option based on that alone, but when I look at them and then think about the amount of volume they have, I worry that they may be overkill and turn the Tremolino into a dog on the water. They are quite massive. One of the interesting things is both boats share the same distance between beams 94.5” center to center with the Getaway using a more robust foreword beam and a rear that is the same size as the fore and aft beam of a Wave. It’s nice to have all these boats and boat parts around to look at and measure as I’m more of a 3D builder. I’ll sketch concepts and design ideas out on paper, but then I need to get materials out and start positioning and building things is scale to truly get an understanding of how things might work or not work.

    image.jpg
     
  13. Corley
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    Corley epoxy coated

    I've sailed my early Trem with the Hobie hulls as floats quite a bit. Honestly, it's not bad, not a powered up platform but it works and is very forgiving you can even push a float underwater (which I've done a few times to see what happens) and the boat keeps going seemingly unaffected. Once you start boosting float volumes you have to give more thought to proper (heavier) waterstays and you get onto that whole global loads treadmill where you have to revisit a lot of areas to make sure they are strong enough.

    I guess it depends what you want to do with the boat. I think it's enjoyable if you accept it as designed and there are a bunch of things that might be better served by building a new design rather than trying to up the performance of an old day boat. It seems to me you will be doing a lot of building anyway with the raw materials you are considering but I do accept there are a bunch of people who don't like building hull shells and prefer to tinker things together.
     
    Last edited: May 19, 2019
  14. W17 designer
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    W17 designer Senior Member

    Working backwards, I agree with Corley's general viewpoint to keep the boat fairly close to being 'as is' as far as design is concerned.
    I think I've finally guessed what was meant by 'the curve' ... the curved forward beam over the cuddy ;-) If that's correct, I can shed some light on that. First of all, Newick often passed his akas (beams) over the cabin top as it allows access under it. If the beam was straight, it cuts right across the access. Also, the curving of the spar does slightly stiffen it, as bending alloy like that 'work hardens' the material, slightly raising its strength and rigidity. But other than that, a straight beam can work fine, though personally I would pause, as it will not retain the Tremolino design or cuddy access if you change it.
    If you fit larger buoyancy amas, you'll either need to use larger section beams or you can add waterstays that will take most of the load.
    Using new amas of different depth, you should set up the beam height at the ama, so that the ama keel just touches the water surface ... perhaps 1-2" in. This way, the windward ama will quickly lift out when sailing and you will have virtually all the ama buoyancy volume available to you on the leeward side to resist heeling. I would stay with the same location for the beams, as the boat was designed to take the loads there. Personally, I really don't like those hulls with the fixed keel, as they have a LOT of wetted surface that will slow ANY boat. Those keels will slow the boat turning, but perhaps you might think to use the 2 Getaway rudders and try removing the original one ;-)
    Personally I'd prefer to see H18 hulls on this boat as a minimum.
    Good luck with the conversion
    www.smalltridesign.com
     
    Last edited: May 19, 2019

  15. Corley
    Joined: Oct 2009
    Posts: 3,710
    Likes: 156, Points: 63, Legacy Rep: 826
    Location: Melbourne, Australia

    Corley epoxy coated

    My other thought is why not build the floats that Dick Newick drew for the Tremolino? You say you want to "save" the boat but what does that mean if the majority of the boat is not a cohesive whole? Here is GC Brehec's boat, the plans are available from Pat Newick. Keeps the original spirit of the boat and gives you bigger floats that look good.
     

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