Fast Launch 26

Discussion in 'Powerboats' started by Pericles, Jan 30, 2008.

  1. EStaggs
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    EStaggs Senior Member

    Tad, run your numbers against the S&S commuters and Reuel Parker's commuters as well. Jacques penned his design with an eye to those boats, as well as Bolger's Blackbird design. Lightweight commuters capable of crossings. The other boats, however, are all warped plane boats with a slightly higher speed potential.

    I think another feature of his boat isn't necessarily outright efficiency. Its a development of efficiency v. construction ease. When you see that the V form and the flat bottom form are within 1-2 bhp, and construction time can be significantly reduced (bear in mind his customers are not shops or pros, but backyarders like myself) with very similar performance characteristics, it makes some sense.

    I find myself drawn to your Alder design, which is extremely similar hull-wise to the FL26, in a dimunitive size.

    For the readers:

    Alder:

    [​IMG]

    FL26:

    [​IMG]

    In combining his construction method (developable panel cored composite) with the specified cruising grounds (Florida/Carribean/Gulf), I think the design stands well. His method would not allow for round bilges or a round hullform such as your methods will.

    With that in mind, do you still find the hull a poor adaptation as compared to a V, which with his method would have to be developed? Bearing in mind there is no strip hybridization in his repertoire, the V sections become either very deep or rather inconsequential when built in 3/8" okoume core.

    E
     
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  2. Tad
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    Tad Boat Designer

    E,

    There really is no way that I have to compare this mythical (until built) boat with any real boat. Especially as I have no direct information on the boats you mention. Published numbers are highly suspect; I don't believe anyone's weights unless I measure floatation and have the hull model to check for myself. I have no way of knowing what this boat will actually weigh when its built, thus the "real numbers" are elusive.

    I agree the flat bottom can seem to simplify construction but I think it's a chimera. Compared to a vee bottom you have eliminated one (stitch & tape) full length seam (centerline) and two edges that must be trimmed to shape. That's all! You still have to make chine logs (or not), and the rest of the boat is the same. As Phil Bolger says, amateur builders will build boats that appear simple to build.

    I firmly believe a flat-bottomed boat will be less useful and less valuable long term. If you are going to build a boat, build the best boat you can with the materials and time at hand. Around here we have a wind against tide chop of about 2' height that would be murder to buck in a flat bottomed boat, never mind going offshore. I know a vee bottom of these proportions and weight could be a real sweet ride in such a chop.
     
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  3. EStaggs
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    EStaggs Senior Member

    Interesting view Tad.

    The next boat I referenced was Reuel Parker's commuter:

    [​IMG]

    Here is a quote about the boat built:

    I do know that the FL26 is designed to keep her forefoot in the water at all speeds to reduce pounding, but obviously until there is an existing copy, you are right about having trouble making empirical points. I just see that using plywood cored composite to create a v hull on this boat would cause it to be significantly deeper in that the conic sections of the plywood force the v to either be deep with a high deadrise angle or shallow with a low angle, thus providing very little improvement in ride, especially when the boat is designed to keep her toes wet.

    E
     
  4. Tad
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    Tad Boat Designer

    E,

    I don't know where the forefoot might be at 18mph, but I do have some thoughts.....given the pic above.....

    Yes, a vee would be deeper. There is a very honest piece by Reuel Parker on the Commuter 36 at age 10 in WoodenBoat #199. Unfortunately it presents some information that conflicts with what you post above and nothing on actual weight at all. He states 17 knots cruising speed burning "about" 5gph with a 90 HP Honda. Top speed was "about 21 knots".

    "Driving into chop 12" or larger (in winds over 10 knots), it becomes necessary to slow down to prevent hard pounding.
    The Commuter 36 is not an offshore powerboat."
    Apparently the owner lent the boat to friend who drove her so hard into a head sea that the #2 bulkhead (guessing aft end of vee-berth) was broken at centerline. Reuel has since designed an alternate deeper v-eed bottom with 12" of draft (4" greater than the original) and displacing 6000 pounds.

    Well "about 5gph" might be 62 HP or it might be 44HP, I have no figure on specific consumption for the Honda.
     
  5. charmc
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    charmc Senior Member

    "Scanning through a large number of tests, I found that most 3000 lb production boats had moderate to deep v hulls and hit that speed at between 2500 - 3000 rpm. HP ratings ranged from 150 - 225. Checking mfr's power curves, I found that 2500 rpm typically yields about 50% of peak power. That translates to at least 75 - 110 HP.

    No, this isn't the precision needed for an exact comparison, but it seems to indicate that the FL26, at 50 HP for similar performance, represents a significant advantage in operating costs."
    charmc

    Tad,

    While you may be right that published weight figures are often inaccurate, I was comparing data from production boats, Sea Ray, Grady White, etc. The inaccuracy of weight data on such boats, in my experience, is typically on the low side, i.e. they are usually heavier than the marketing literature describes. The hulls I described tend towards the "deep vee" that marketing types promote so the buyers think it's a derivative of a racing hull.
    You are describing carefully designed custom boats, and, as I stated, I agree that the efficiency advantage of the FL26 compared to other custom designs will be less than its advantage over production designs. There is still some advantage. I stand by my numbers.

    Your subsequent comments to E about the versatility of a vee bottom design to the FL26's flat bottom aft are valid, as are his about simplicity of construction and the market for this design. I'll add that my years of operating power boats from 17' - 31' in the North Atlantic and numerous inlets has demonstrated to my satisfaction that shallow vee bottoms have no measurable ride improvements over flat bottoms.

    Again, keep in mind that the FL26, like the Reuel Parker design discussed, is not intended to go offshore as a primary "mission", while being capable of going offshore if desired.
     
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  6. Pericles
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    Pericles Senior Member

  7. Tad
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    Tad Boat Designer

    Charlie,

    Apparently I'm not stating my thoughts very clearly.

    In post #11 you stated;
    "The FL26 is designed along traditional lines, as an economical and easily driven hull, giving a reasonable cruising speed with less than half the power required to drive a hull whose V is carried to the transom."

    In that statement I assumed that you meant a boat of similar dimensions but with a vee bottom. Apparently what you meant was a 26' Sea Ray that weighs 6000+ pounds and is 9' wide? To me it makes perfect sense that a boat weighing twice the proposed 3000 lbs of the FL26 should use twice the HP for similar speed. I don't see how that validates the FL26 hull form?

    So in post #12 I stated;
    "Please show me a 26' LWL, 3000 pound, 8' beam boat that requires over 100HP to manage 15.6 knots?"

    So far no specific examples have been posted. Perhaps there aren't any examples of this configuration, or they are just not easily available. At any rate I apologize for my confusion.

    If you are comparing the FL26 to a production boat advertised as weighing 3000 lbs, that boat will only be about 20' overall. Shorter length will require more power for similar speed. If you are comparing the FL26 to a production 26' boat, the waterline will be shorter (much shorter at pre-planing speed), the beam will be greater, and weight will be far greater. And yes, every production boat actually weighs more than advertised, and the real weight is unknown. In any of these cases the reason for higher required power is obvious, increased resistance due to shorter length and greater weight. Thus (to me) your comparison is invalid. I.e., you are comparing apples and oranges.

    My postings above questioning the quoted capabilities of this design are written in hopes of avoiding a rash of inexperienced folks drowning after building flat-bottomed "offshore capable" boats. This very shallow, low sided, protected water cruiser will be in big trouble if she lost power and a wave came aboard. The cockpit is huge, and unless it is equipped with relatively huge drains, the boat is unsafe "offshore". ISO standards on cockpit drainage will require (roughly) a minimum of two 6" diameter drains for a cockpit this size. To characterize this type of boat as offshore capable is (to me) irresponsible.

    Tad
     
  8. charmc
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    charmc Senior Member

    Tad,

    I'm not a designer, and nothing I've posted should be taken as critical of your designs. If anything I said sounded like design criticism, I'm sorry, that was never my intent. I have a lot of respect for your work and for your contributions to this forum.

    But no, I haven't been so foolish as to attempt to compare 6000 lb+ boats with 3000 lb vessels, or 20' boats with 26' boats. There were slight variations in waterline length, but no beams over 8' in the tests I selected (most were center console outboards, to stay within the weight range). Unfortunately, I can't cite specific side by side models here, as what I did required a few hours of research (it is damn difficult to find boats that size that don't weigh a jillion pounds), and I won't do it again. I didn't save individual tests, but I made notes and presented some typical performance figures. Yes, that means you can criticize my method and results as imprecise and therefore limited. In fact, I said that myself.

    My point about the FL26 was simply that that particular design appears to have an edge in operating costs over others I've seen in that size/weight range. A very large edge over production boats, a smaller but measureable edge over custom designs. When I said 18 mph with 50 HP was economical, you said that no boat of that size/weight range should require more than 100 HP for that performance. I understood that to validate my position. I continue to stand by my numbers, and I believe your own numbers (I assume yours are not "wildly inaccurate" :) ) show a small efficiency edge to the FL26 compared to your Downeast 26.

    On the subject of whether it is a good design as a boat for people planning to go offshore occasionally, I have to agree with your comments above. PAR made a good point earlier, stating that such a boat is offshore capable ... in the hands of a good operator ... the Wooden Boat 199 article about the 36' Commuter supports his point. When evaluating a boat, I tend to think in terms of my own experience. The FL26 will not be dry, comfortable, or easy to handle offshore if caught in a squall, but I don't think I'd be worried. I forget, though, that inexperienced people fall in love with a dream and build a boat.

    So I find myself agreeing that characterizing the FL26 as offshore capable, without any caveats, is perhaps misleading. I don't know if I'd say irresponsible, but there should be a more detailed description of "offshore capable", maybe by adding "in the hands of an experienced skipper" or similar wording.

    I would recommend the FL26 as a good looking, economical boat for folks to run in sheltered waters. For myself, I would, in fact prefer your Downeast 26, even though I'd pay a bit more to run her.
     
    Last edited: Feb 19, 2008
  9. EStaggs
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    EStaggs Senior Member

    Interesting, as I lost track of this thread.

    In Jacques' words, he actually is very adamant in the plans information and any inquiries about the boat about her usage. He is very quick to point out that the seaworthiness of the boat rests in the operator, not in the design or inherent abilities of the boat. I would venture that he agrees with you on seaworthiness 100%.

    I would, however, like to see how your 26 compares side by side, as I was on your site the other day looking at her. I think it would be informative for those of us who are looking at maximizing efficiency while retaining a 20-28kt speed burst ability.

    As always, very informative post!

    E
     
  10. Pericles
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    Pericles Senior Member

    Eric.

    A more "like for like" comparison would be between Jacques' DE 25 and Tad's lovely DE 26, which I have admired since the plans were published. Probably the long cockpit version DE 25 is the nearest match.

    http://www.bateau.com/studyplans/DE25Cockpit_study.htm?prod=DE25Cockpit

    On balance, I believe the wide chine flats that the DE 26 possesses will encourage it to plane earlier, by one knot, probably!

    http://www.tadroberts.ca/services/small-boats/down-east26.php

    Tom Lathrop incorporated wide flat chines into his Bluejacket boats with remarkable results.

    http://www.bluejacketboats.com/designing_liz.htm

    In the end, it has to be about good seamanship and making the right choices whilst at sea. :D :D

    They are all great vessels, each of which is a credit to their designer!

    Pericles
     
  11. EStaggs
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    EStaggs Senior Member

    Im seriously considering doing a modified DE23 of Mertens design with an open aft section of cabin such as the 26 of Mr Robers, but after seeing that the 26 utilizes the SAME engine as the 23, and the same fuel burn rate, with similar performance numbers (only slightly slower), Im considering it.

    Obviously its a more complex build as I dont think Tad's boat has true conic sections allowing plywood to be used for all panels (I believe it requires some cold mold/strip type work on the bow), but the extra few feet make an IMMENSE difference as far as interior layout is concerned, and a much more usable aft deck.

    I am also curious if it is bracketable, as any boat this size will be used for mothershipping our sea kayaks in the San Juans/Puget Sound/Gulf Islands.

    E
     
  12. Tad
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    Tad Boat Designer

    Oh boy...a bunch of posts in row here....

    First....I don't want to get into a "my boat's better than yours" type of argument. It isn’t. I believe all boats, given reasonable design and construction, have their place....except for those three story white ones with the black windows....you know...

    Second....I am embarrassed about the Downeast 26 name, I had no idea of the existence of Mr. Mertens DE25 or I would have done something different. Actually I have changed the name to the Berry Point 26, but that hasn’t made it onto the website yet...and it may be too late.

    Third....Seaworthiness is a huge subject but we (designers) cannot say it all rests with the operator, that's a copout. Part of being a designer is sending folks out in peril of their lives, as a designer you had better take that seriously. Home builders are often neophytes at the boating business and are perhaps more apt to get into trouble. I believe one has to think about this, a sunny day on a small lake is very different than a cold night offshore. Where is trouble more likely to crop up?

    Fourth....E...given the same beam and depth, the longer boat will be faster (or use less power for the same speed) even though it weighs more.
     
  13. EStaggs
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    EStaggs Senior Member

    Tad, is your boat capable of using a bracket for the outboard?

    Is there a place I can find more info than on your website (study plans more descriptive than the .dwf files)? Im finding this boat to be very interesting.

    E
     
  14. Pericles
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    Pericles Senior Member

    Eric,

    Jacques' DE 25 is the stretched version of the DE 23. I purchased plans for both the LB 26 and the DE 25 Long Cabin version as I like to hedge my bets.:p Nesting the marine ply would be the greatest difficulty in stretching the DE 25 any further and could put costs up significantly

    It would also have implications in the UK with compliance to the RCD as the finished vessel would not be as the designer calculated. It can be done but, the documentation would cost more.

    http://www.icomia.com/technical-info/document.asp?TI_ID=11

    Tad's Berry Point 26 has more of the look of a Down East lobster boat, see page 52. NIKI.

    http://www.woodenboat-digital.com/woodenboat/20070910/

    The nearest Jacques gets to that look is the Novi 23.

    http://www.bateau.com/studyplans/NV23_study.htm?prod=NV23

    Its the three window look of the DE 25 that ticks my box, as it is with the Tolman Skiff, although the wide variety of cabins styles on a Tolman leave a builder with many choices.

    http://www.fishyfish.com/tolmanskiff.html

    As mentioned in an earlier post, they are all great boats. We are spoiled for choice.

    Pericles
     
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  15. EStaggs
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    EStaggs Senior Member

    P, I have no interest in stretching the designs. I would build the 23 as it sits, or Tad's 26 as it sits. Stretching that would be a hassle, and the 25 is really quite similar in length to the 26 if that were the case. The problem being the 25 requires more power for the same speed (Id guess Tad's lifting strakes are probably the efficiency-builders here).

    I have that issue (been a subscriber for years) and liked NIKI, but she wouldn't be too friendly in the strait of Georgia or Juan de Fuca on a wind-against-tide day. I need a bit more freeboard. This same freeboard issue is what keeps me from getting FL26 plans. My current project (Mertens LB22 NINA) has the same low freeboard, so it will get very limited use outside of the lake we live on.

    Freeboard is uber-necessary because I like to salmon and halibut fish on occasion, both of which take place in areas that need a boat with freeboard. The outside of San Juan island takes the brunt of the Juan de Fuca waves, and the trolling route causes the boat to take the majority of waves directly to the side of the boat. Nauseating roll ensues, etc etc. Ive had a few too many spray-over-the-rail events to have a shallow boat out there.

    Im rather fond of the Berry Point (hoping to learn more about it), and Id love to see the pilothouse fit out, to get an idea of accomodation. This is probably a year out (rowing shell and Tom Hill's Long Point skiff are due up first), but something that Ive been putting a ton of thought into.

    E
     
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