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Dec 03, 2008, 05:10 PM
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doomracing's Avatar
true, but if you intend on trying to run with a USOM your going to get your butt handed to ya.
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Mar 04, 2018, 04:28 PM
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Jekyll/Hyde a Soling 1M for US1M?


Hi. I'm building a Soling 1M, mostly because there are active clubs here at home (Ohio) and also in Florida (right inside the resort my wife and I are planning to retire to fairly soon).

I already know that the S1M qualifies in the US1M class - but I'm certain it's not at all competitive in S1M standard form (10 lb, short wide blob keel)

I'm building mine to have a removable keel, and I'm seriously considering building a US1M style deeper bulb keel for her. I'd like to hear people's thoughts on what things could be done (two categories: temporary, reversible mods, and permanent (S1M disqualifying) mods) to modify a Soling 1M to be more competitive in the US1M class.

Obviously, the keel and overall weight are available for reversible modification, and the rig would have to be retuned to rebalance the boat for each keel. I think the 4lb weight reduction could make the boat much quicker, while the deeper bulb provides comparable power and righting moment between the two configurations.

The question here is, what else would you do? And, how close do you think YOU could get a S1M hull to the front of a US1M fleet in a race if you did everything that was reversible, or everything that was possible, to build an S1M into a US1M boat?
Mar 04, 2018, 11:46 PM
Kevin Gault
poltergeist's Avatar
Steve,

I can't see getting a Soling 1 meter up to speed with any of the more current US1M designs. The Soling hull's waterline length is substantially shorter than a modern US1M. I'm not sure of the Soling's beam, but my two US1M's have beams of 5" and 5.5". I'd also be concerned about how the keel attachment structure inside the hull of a S1M would hold up under the stress of a much deeper fin/bulb style US1M keel. If you're looking for a modest cost US One Meter, I've had fairly good luck modifying a Dragon Flite 95 into a US One Meter. https://www.rcgroups.com/forums/show...S1M-conversion

Kevin
Mar 05, 2018, 12:08 PM
Registered User
Thank you, Kevin. That's a big part of the question: how far from "USOM optimum" is the Soling hull shape? And, with the lighter keel for 6lb displacement instead of 10#, the waterline length difference is magnified. As for the keel attachment, my thinking is that the USOM keel is longer-but-lighter, both should provide roughly equivalent righting moment* and applied torque on the heels trunk. I'm concerned with strength here even with respect to the Soling keel weight, so I'm building extra reinforcement here anyway.

* (decided to try a rough calculation here in my head, in my car, on my lunch break. Worst case scenario, with boat heeled to 90 degrees... The Soling has 6.5# lead, approximately 9" offset from the 90°CB, torque would be about 58 inch-lb. USOM keel on the same 3.5# boat for the same torque would have about 3.625# lead in a bulb offset 16" from the 90° heel CB, bringing the total boat weight to 7.125#. Since the Soling is wider (also contributing to righting moment at lesser heel angles), I would be OK with using a bit less lead to get the boat a bit closer to 6lb overall. So, I still think the keels' applied torque at the hull are roughly equivalent to each other.)

Of course, I could build out a straight-up USOM design... I might scratch build one anyway (if I find a club nearby that runs USOM - no point if there's no competition nearby... ). But the point here is to avoid campaigning a complete second (and more expensive) boat, to explore the feasibility of building out a Soling so it could be set up to hold its own (not necessarily dominate, but at least not be humiliating) in a USOM race.

I have two additional motivations for this idea... Partly, I'm hoping that this could spur discussion of "what makes USOM fast (especially as compared to S1M)?" Also. if a strategy emerges for modifying S1M boats into fairly competitive USOM entries, any club with a big S1M fleet could easily find a few guys willing to race as USOM, which would help expand racing opportunities for "orphan" (no local club) USOM boats out there... all of which could promote this class.
Mar 05, 2018, 12:39 PM
Registered User
I totally agree that a Soling One Meter could not be a competitive US One Meter. The hull has way too much wetted surface and the hull form is outdated. Plus you have the problem of building up the hull and deck to support a fin bulb keel and a carbon high aspect mast. Even properly locating the fin to have a balanced boat would be a challenge. In the end you would likely wind up with one boat that is likely not competitive in two classes. Finally, although once widely sailed, today the US One Meter population is scattered in pockets around the US. Might not find any near where you decide to settle in Florida.
Mar 05, 2018, 02:33 PM
Registered User
Melbourne Fl has a big fleet of US-1 Meters.

In case you didn't know

Bill
Mar 05, 2018, 03:50 PM
Registered User
Thanks, Bill - that is good to know! I've found a USOM club that sails just over an hour's drive from me in Ohio, too.
Mar 05, 2018, 06:52 PM
Kevin Gault
poltergeist's Avatar
Steve,

I guess I wrongly assumed that you planned to put a max-height US1M style rig/sailplan on the boat. That, along with a max-depth fin and ~4lb bulb I think would put significantly more stress on the hull/keel interface.

That said, it can't hurt to try (unless something breaks). Against early vintage US1M's it might do OK.

Kevin
Mar 06, 2018, 12:22 AM
Registered User
Quote:
Originally Posted by poltergeist
Steve,

I guess I wrongly assumed that you planned to put a max-height US1M style rig/sailplan on the boat. That, along with a max-depth fin and ~4lb bulb I think would put significantly more stress on the hull/keel interface.

That said, it can't hurt to try (unless something breaks). Against early vintage US1M's it might do OK.

Kevin
That was a completely fair assumption - along with swapping to a USOM bulb keel, I would almost certainly maintain a USOM spec rig for it. The extra mast length would make it easier to design sails (and distribute area between them) to balance the rig to the bulb keel. Plus, I think that being able to add some sail shape - getting away from Soling's "one flat panel" sail - would definitely add some performance. In both classes, sail area is about the same (592.25 for S1M, 600 for USOM), but the extra 14" of mast height does move the center of effort (CE) higher by about 5", which would create more heeling torque at any given wind speed. The thing is... if a USOM rig applies 20% more heeling force at any given wind speed, that just means that the S1M rig applies the same amount of heeling force in a 20% higher wind. To my mind, the hull/keel joint doesn't care whether the boat is heeled by a taller mast, a shorter one, or by the owner holding the hull in his hands at an angle - the torque at that joint should be simply the product of the keel weight times the horizontal offset from the joint, and the righting moment is the product of that weight times the horizontal offset to the hulls center of buoyancy (at that angle). In the water, under sail, torque and righting moment are somewhat reduced by the partial buoyancy of the lead (roughly speaking, 6lb of lead will displace 1/2lb of water) and by lift forces acting on the fin surface. (This lift force is substantial - just as righting moment is a torque COUPLE between the horizontally offset forces of ballast weight (down) and buoyant force (up), the sail's heeling moment is a couple between the vertically offset forces of the wind on the sails and the horizontal acting component of the fin's lift force (at 45 degrees of heel, the horizontal and vertical lift forces would be equal, and the vertical component would reduce keel joint stress as the horizontal component tries to pull the keel out of the hull... ). Without that lift force - if we imagine replacing water with some magical fluid of the same density but zero viscosity and zero inertial resistance to flow around the fin - in that hypothetical fluid, our boats wouldn't "sail" or steer, instead, at any wind speed they'd stand up straight and be blown downwind.) So, the absolute worst case for the keel joint (aside from underwater impacts or dropping the boat while carrying it..) is when the boat is held in the air by hands on the hull sides, holding the hull at 90 degrees of heel. But I can strengthen the hull-keel interface - I once repaired a cracked keel former on a Farr 37, which went on to race for another decade...

I think it's worth trying, even if "Bride of Frankenstein" isn't ever competitive as a USOM hull... I think a LOT could be learned about boat performance, rig tuning, etc.., which could benefit a sailor in either class, or a designer/builder in USOM. I'm not thinking of my hybrid as an end result, more of like an experimental platform with a very well established performance baseline. Winning isn't everything, I'm as interested in the challenge, and in the opportunity to learn. The BEST scenario i can think of would be if I could find a club which races S1M and USOM concurrently (both classes start together, sail same course in the same winds, finish as they are able..), so I could apply changes and see if they help me pull ahead of the S1M pack, and how close they get me to the USOM pack. In big-boat racing, concurrent racing is done all the time - starts get more crowded, but boat speed differences generally separate the classes before they reach the second mark.

By the way, I did find this - http://www.theamya.org/boats/us1m/us1mcons.php - which includes plans for 14 different USOM boats. I just printed out the "Advance MKIII" plan, and laid my Soling forward bulkhead over the Station 5 contour. The MKIII contour is outside the bulkhead contour everywhere, but never by more than 1/8" until the last 3/4" of freeboard, where it flares out about 3/8". In profile, the MKIII is deeper and flatter in the forward third, with a straight, almost vertical bow profile, for a finer entry and more waterline length at its lighter displacement. Ironically, being less spherical, the MKIII should have MORE wetted surface than a Soling hull at the same displacement. The MKIII mast is an inch aft of my Soling's, with about 50 in^2 of sail area reduced from the main and added to the jib. The rudder is much farther aft on the MKIII. But, overall, given the same sail area and keels, I'd bet these two hulls would be fairly similar performers - I think the better sailor would win in a head to head match regardless of which boat he sailed. (Which might just mean that the MKIII is an obsolete hull now - the drawings aren't dated, I can't say that MKIII isn't a 30 year old design that hasn't won a USOM event in this century... are there any MKIII sailors out there who could weigh in here?)

Anyway, thank you (everybody) for your participation here - I really do appreciate everyone's input!
Last edited by SteveWin; Mar 06, 2018 at 05:44 PM.
Mar 11, 2018, 08:01 PM
If it floats....sail it!
FoamCrusher's Avatar
Steve:

You quoted the sail area for a US1M as 600 sq inches. That is the total measured triangle of both sails. However, a US1M has about another 150 square inches of sail area that is not measured by the rules - the area in the unmeasured foot and roach of each sail. That extra area makes a big difference in performance. See the class sail control drawing here: http://theamya.org/boats/us1m/us1mimg.php#Dimensions:

And unlike a S1M where there is a sail template, as long as the measured triangles total 600 or less and the foot and roach limits are not exceeded, you can change the ratio of the main to jib areas anyway you like. Ken Bauser of KB Sails has several patterns that are specific to certain designs. I have a set of experimental sails that heavily bias the jib area that I put on a modified T37 that was stretched to 1 meter. It was fun to build and play around with, but it was not competitive.


Steve Vaczovsky
US1M Class Secretary
Mar 16, 2018, 10:23 AM
Registered User
Quote:
Originally Posted by FoamCrusher
Steve:

You quoted the sail area for a US1M as 600 sq inches. That is the total measured triangle of both sails. However, a US1M has about another 150 square inches of sail area that is not measured by the rules - the area in the unmeasured foot and roach of each sail. That extra area makes a big difference in performance. See the class sail control drawing here: http://theamya.org/boats/us1m/us1mimg.php#Dimensions:

And unlike a S1M where there is a sail template, as long as the measured triangles total 600 or less and the foot and roach limits are not exceeded, you can change the ratio of the main to jib areas anyway you like. Ken Bauser of KB Sails has several patterns that are specific to certain designs. I have a set of experimental sails that heavily bias the jib area that I put on a modified T37 that was stretched to 1 meter. It was fun to build and play around with, but it was not competitive.


Steve Vaczovsky
US1M Class Secretary
Excellent point, Steve! Thank you!
Mar 18, 2018, 08:59 PM
Registered User
SteveWin:

You'd be so much better off starting with any used US1M hull than to put any effort into a Soling hull. It's really not worth the effort. What you'll get out of this little project will sail, but won't perform very well. There are some older boats around, just looking for someone to update them and tune them up. I grabbed one at an estate sale when a local sailor passed, took over 5 ounces of out of it and truly updated it, and it wasn't a slow boat to start with (but it was overbuilt). I enjoy those types of projects myself. I then sold it to a new skipper for what I paid, plus parts I added. Lots of old boats around that just need some love.
Apr 02, 2018, 03:54 PM
RB

New Boat


Hello All,
I’ve recently finished a new boat that might be considered a US One Meter. That was not the original intent but it meets the class specs. I started out to build something that would be fast and fun. I would appreciated any comments on the specs below, considering increased displacement, wider, narrower, more sail etc. Asking another way – what are the currently optimum specs for a US1M? There are no US1M locally – nearest is probably Buffalo; so I have been unable to compare it with similar boats.

LOA 1000mm
Bm 180 (7”)
Draft of fin 340 (131/2”)
Displacement 2.5kg (5.5lbs)
Wt of bulb 1.2kg (2.64 lbs)
Sail Area 650 sqin +/- including roach (on main only)

The sail area is intentionally less than permitted as I was concerned the boat would be overly tender. Thanks,
Richard
Apr 02, 2018, 04:18 PM
If it floats....sail it!
FoamCrusher's Avatar
Richard: Welcome to the class.

The “optimum” for a US1M really depends upon the conditions where the boat will be raced. Light wind venues favor a wider hull in the 8” range and stronger winds seem to favor narrow boats in the 150-125mm beam range. In multiple day all day events with some of everything, somewhere in the middle (the Sterne’s Venom) seems to do the best. However, that also depends upon the skipper’s skill.

Most boats displace between 5.5 and 6.0 pounds with a bulb weight around 4 lbs - less in light winds say 3.5 lbs. I had one boat with an aluminum fin and a 6lb bulb that displaced 8 lbs that was a dog in light winds, but very hard to beat in 12+ mph when it could carry an A-rig and others had to switch to their B rigs.

As far as sail area, the more the boat can carry without becoming a submarine on a run the better.

See how yourbboat sails in your venue and if it is too tender, I would go to a heavier bulb. Also using the full depth of keel (14.25” from the bottom of the hull to the lowest point on the keel ) will help, but if you are not going to compete with it, what you have is probably fine.

Steve Vaczovsky
AMYA US1M Class Secretary
Apr 07, 2018, 08:56 PM
RB
Steve,
Thanks for your comments. If I add 500gr to my bulb the boat gets near numbers you offer, about 6.2 # with a bulb of about 4#. However I am at 5.2 # w/out battery and about 650 sq in of sail area - about 100 sq in less than the max (including roach). I was, am, assuming there is a trade for less displacement and less sail area to achieve similiar performance of a heavier and full sail boat. Where might be the middle road on this ? I guess I need to get head to head with an US1M to see. I could do the sail area - displacement calculation, but I don't know if it is valid for models. Thanks again.
Richard


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