how to evaluate a heavy hull

Discussion in 'Sailboats' started by gedanken, Oct 15, 2014.

  1. gedanken
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    gedanken Junior Member

    Hello! New here, hoping you all can offer some advice.

    I'm looking at an Atkin "Erin" double-ender as a part-time liveaboard. The hull is strip-planked cedar with a cold-molded overlay. She's quite heavy, 32,000lbs for a 36' (on deck) boat, 31' LWL. I've been told the cold-molding was added a few years after the initial construction, which accounts for how heavy the hull is.

    Some numbers I've run:
    D/LWL = 480
    LWL/Beam = 3.1
    Ballast/D = .27

    For sleeping in a marina, maybe this isn't so bad, but I would like to think the boat was capable of some reasonable cruising. Maybe not ocean crossing, but up and down the west coast as an ultimate goal.

    So how should I evaluate just HOW tender this boat is? I understand this type tends to hobbyhorse but don't have enough experience to judge what's normal, tolerable, or dangerous. I'll be going for a test sail this weekend. Would it help to time the periods of pitching & rolling? What other practical benchmarks might I look for?

    I have sailed small daysailers in the Puget Sound and San Francisco Bay, I just don't have any substantial cruising history.
     
  2. PAR
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    PAR Yacht Designer/Builder

    Erin is heavy because of her hull volume, not necessarily her build type. This is a pretty fat, slack bilge boat, so you can bet she'll be heavy. She carries about 8,500 pounds in ballast and knowing this is a Billy design, the ballast ratio will be fairly low, say 27%, so some simple math brings us to over 14 tons (long).

    A cold molded skin over the strip planking will not add that much weight, assuming it's done in the usual way.

    Compared to a modern sailor of similar size, she'll seem initially tender, but will firm up like a rock after some heel and her bilges "engage". This is normal for this type of hull and something you'll get use to pretty quickly, once you build confidence with her. Her motion will be relatively slow and predictable, as will her maneuverability, again compared to a modern yacht. This boat will not back down to save it's life, so learn how to back a fill or slow speed motoring maneuvers will be trying. No, this hull doesn't tend to hobby horse, if built to plan, particularly her ballast, which is spread out across 3/4" of her LWL. This a very effective pitch dampener. This coupled with her balanced WL's and she'll be well mannered, if a bit slow and needing a good bit of wind to get away from a dock. This boat is a capable ocean crosser too, well suited for trade wind work.
     
  3. gedanken
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    gedanken Junior Member

    wow, that's fantastic information, thanks. So a ballast ratio of .27 is reasonably normal for a William Atkin design?

    And I'm a little confused at how a slack-bilged boat like this would be expected to stiffen up dramatically as she heels, compared to a more hard-bilge design. I thought hard bilges created MORE stiffness.

    dead on about backing down and slow speed maneuvering. The current owner already warned me about that.

    thanks so much, this is certainly the kind of thing I wanted to hear.

    I know the upwind performance will not be up to modern standards, but what should I expect? Should she be able to make progress upwind in say 10-15 knots of wind?
     
  4. PAR
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    PAR Yacht Designer/Builder

    She will sail fine upwind and will tack through 90 degrees, but she's just what her 3/4 - 7/8's of century old hull form is, lots of wetted surface, lots of volume, lots of displacement, etc. 10 knots of wind will make windward work possible, though light air may be challenging, but more because of an expected and relatively low SA/L on a massive D/L hull form. She'll be in her element with 15 knot winds.

    There's no "normal" for ballast ratios, though I'm very familiar with Atkins design. I actually own John's last commissioned design. As an Erin type hull heels, she'll bear down on the ever flattening and ever increasing volume of her girth and bilge, so she'll firm up nicely around 12 to 15 degrees of heel. To a modern sailor, initially, she'll seems quick to flop over and heel, but (again) this is normal and should be expected for a hull shape like this. There's a huge amount of hull girth, just waiting to bear down once she heels over, which is what firms them up.

    The real questions you should ask the current owner are what's the ballast made out of (and hope it's not boiler punching and concrete), when was the last time she sank, last time the boat was hauled and lastly get her surveyed by someone the current owner doesn't know and someone that's experienced with this type of yacht. Most surveyors don't know these boats, nor what to look for, so get a wooden yacht specialist.
     
  5. bpw
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    bpw Senior Member

    Our 28' Atkins Inga is right at 50% ballast, so some of the double enders have pretty respectable ballast ratios.

    Ours flops over a bit and then hardens up as well, but I sure wish Billy had put a bit more keel on ours. Seems he was trying real hard for shoal draft and made the compromises to get there, I am sure that had something to do with the extra ballast.

    Erin looks like she will be quite a bit better up wind than our boat is since she has a more defined keel. We actually added depth to our keel to create a bit more lateral surface.

    Ours is a Ferro-cement hull with wood decks and we have taken her from SF to Uraguy via Chile and the Falklands, so these boats will get you there, just slower than something more modern. We thrashed our way upwind into Falkland Island Sound in a force 8, its slow and tacks are ugly but she will go.

    These boats tolerate extra weight very well, so I doubt some extra planking thickness will do much harm to performance. I would be worried of the cold-molding had been put on to "fix" a hull that was in bad shape, inspect the inside very well to make sure the interior frames and planking aren't wasted.
     
  6. SukiSolo
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    SukiSolo Senior Member

    Totally concur, it was interesting checking out the design and 'going back in time' so to speak. Quite a lot of that type were developed in the UK, but there are some more innovative shoal draft and shorter keel boats from not far off that era, say late 30s'.

    At least she is beamy enough to not be like standing in a shower upwind at 45 degrees unlike some of the really narrow, slack bilge craft.....;)

    Gedanken, you will find that harder bilges will give more initial 'stiffness' so less heel, but when you are laid over in a squall you have 'lost' that, so takes a bit longer to recover. The slacker bilge will heel easily to start with, but then the overall beam starts to factor in and give good 'stiffness'.

    For me personally, I am less keen on the huge wetted surface area with the long keel. A very serious penalty in light air and not good for tacking in confined waterways.
     
  7. gedanken
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    gedanken Junior Member

    wonderful input everyone, thanks so much!

    ballast is lead, so no worries there. boat hauled about a year ago. surveyed about 2 years ago by the owner. will certainly be getting my own survey done, with a haulout, before finalizing any sale. Anyone can recommend a good wood boat surveyor in san francisco?

    I'll start worrying about other stuff besides an overweight hull, I guess. I understand (a bit -- very small bit compared to you guys!) the tradeoffs, I was just concerned that the design might have been compromised by the construction.

    If I was commissioning a boat from scratch, I'd probably not opt for the full keel like this, but otherwise this boat has a few good things going for it. It seemed bone dry inside and well cared for. Interior is somewhat spartan, so access to the hull is good and in my brief tour I saw nothing the least suspicious. Will take a clipboard and flashlight this weekend!

    rig is probably very underpowered. making some rough estimates, it seems to have less than 600 sq ft of sail (SA/D = 9!), rigged as a staysail schooner. There's a track on the foremast that could take a large fisherman, but he doesn't have one at present. Would it be correct to say that a fisherman would not help light, upwind performance very much? Am I crazy to imagine converting to a gaff foresail, and maybe main, somewhere in the future? She already has running backstays for the main mast.
     
  8. PAR
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    PAR Yacht Designer/Builder

    http://www.marinesurvey.org/index.php?option=com_storelocator&Itemid=303&view=map

    This link will get your several. Call each and find one that's comfortable with your yacht. Now, many will say "Oh yeah, sure, no problem", but make him qualify his reply with common things to look for and report what some of these might be here.

    It's very common on larger strip planked hulls, to have a cold molded skin over it, so no worries.

    A staysail schooner rig is the most efficient of the schooner rigs, so converting to a gaff fore will just subtract from her abilities. The boat should have a minimum of 900 sq. ft. (13.7 SA/D) which will work great in the trades, but you'll need quite a bit to get away from a dock. Ideally, for coastal cruising you'll want 1,000 (15.2 @ 15 tons) or more sq.ft., say 1,100 (16.7) or 1,150 (17.5). This will offer much better light and modest air ability, without the need to reef as often as a high SA/D will require. For light air work, you can hoist big genoes and staysails.
     
  9. SukiSolo
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    SukiSolo Senior Member

    One good feature of strip planked/cold moulded boats is that they tend to have lower internal condensation than metal and thin skin FRP/GRP boats. Much better than steel or aluminium and quieter. So more pleasant to live on in many ways. Can also help the 'life' of the boat, if she is used and aired sensibly.

    Take PAR's advice though and get a good surveyor who understands this type of construction. He/she will know all the points to look out for with this type of build.
     
  10. gedanken
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    gedanken Junior Member

    went for a sail last weekend. Had a great time! Boat sails much more easily than I expected. Maybe all the research led me to expect the right general behavior.

    She's definitely heavy, but by no means unmanageable. getting in and out of the slip is (predictably) the most daunting handling issue. Sail area, according to the owner, is a little under 700 sq ft, or SA/D of almost 11. Still, she seemed to go through the water fine. We got passed by 22 foot racers with spinnakers up. bully for them.

    Points surprisingly well. Easily held a course 45 degrees off the apparent wind in 10-15 knots. A little weather helm there. A lot more weather helm on a beam reach, which does surprise me. Steering became a bit of a workout with the wind going above 15 knots. Probably could have reefed the main at that point.

    Boat heeled fairly easily, but I would hesitate to call it "tender". Feels quite stable to me. Got the rail down to the water in those relatively mild conditions. I'll have to trust you all that heeling any more will take a lot more energy. No alarming rolling or pitching as far as I could tell.

    I was wrong about the ballast, the external ballast is is iron. There's 1500# of lead in the bilge.

    I don't see how to easily increase the sail area without major changes to the rig. To keep the staysail schooner arrangement but add 50% more sail, we're talking about taller masts? Just adding overlap to the staysail and headsails doesn't seem much more practical or effective than gaff sails.

    Current sails are all self-tending (except for the jib), so fit in their triangles.


    ok, off to find that surveyor...
     
  11. CT 249
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    CT 249 Senior Member

    To get an idea of the sailing qualities of an Eric, read "A World of My Own"; Robin Knox-Johnston's account of the first solo nonstop around the world voyage. His boat, Suhaili, was an Eric but the plans service was so poor that he did not promote the fact.

    The Westsail 32 is allegedly an Eric and has a PHRF rating of 222, which should give you an idea of the performance.

    Whoops, I didn't realise this was an Erin not an Eric; still if it's the bigger version of an Eric this info may be of some use.
     
  12. gedanken
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    gedanken Junior Member

    thanks for the offer to play along!

    talked to two surveyors today. Both said fairly similar things. "yes, we have experience with wood boats", naturally.

    1) will look for soft wood & cracked frames. will look at the deck construction and especially the hull-deck joint. will look at the "glass" work for delamination. mentioned a compression test. Had opinions about what boat yards around are better. price is quite high, includes a quick "sea trial" on the way to the haulout.

    2) will spike for rot, look for delamination and check the layup quality. look at through hulls, machinery. pointed out that he will only check the rig from the deck, and not do a full engine survey. less opinionated about yards. price is 80% of option (1). will do breif checks underway as well.

    engine is practically new, so that's not a big concern for me. rig is what it is -- I can't imagine anything queering the deal that can't be seen from the deck. I know I'm buying some existing issues.

    honestly, the first guy I talked to gave me such a good impression on the phone that I don't feel like continuing the exercise (and I think I'm unusually sensitive to fast talkers. Haven't met a broker yet that I didn't want to pitch overboard). writing it down now, it is humourous though how much they both seemed to gravitate to lamination issues, which seem like a relatively minor factor. OK, critical, just sorta secondary to the wood frame. Clearly, fiberglass is their bread and butter.

    no questions atm. but will entertain all comments, including mockery of my naivete. Guess I've talked myself into calling a couple more tomorrow. Going to ask the local wood boat co-op if they have a recommendation.
     
  13. bpw
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    bpw Senior Member

    So I should let you know that I am the son of Steve Wedlock, one of the local surveyors and am apprenticing to take over the business, you may have been talking to my dad...depending who you chose I could end up helping survey your boat. Obviously I am biased and think we could do a great job, but I could also recommend some other surveyors in the area who are very good if you PM me.

    With that said, I think the concern with delamination is because the boat has been cold molded over. If this was done poorly it can do a really good job of trapping water and causing lots of rot in hard to see places.

    If anyone thinks this post is advertising I am happy to remove names, just thought it fair to disclose who I am since this is pretty close to home.
     
  14. Fanie
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    Fanie Fanie

    On this forum ? NAH !!!

    I think every one is probably just relieved that you are someone's son.. :D



    Gedanken, post a few pictures will you ?
     

  15. gedanken
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    gedanken Junior Member

    hauled and surveyed today. all went very well. 12.5 tons on the scale this time. When I asked if that's short or long tons, the lift operator shrugged and said "normal".

    whatever. The boat goes when the wind blows, so the decision is made to buy her. Surveyor found no surprises. He seemed impressed by how relatively solid everything is. Lots of little things that could use attention, but the only major item really was the propane installation is not going to fly, but I already knew that. I guess I know what my list starts with!

    one item I could use more input on. The surveyor noted that there are two forward bulkheads, just aft of the vberth, fore and aft of the head and a locker opposite it. The forward of the two is fastened with a few screws to one of the deck beams, and the aft isn't attached to the deck at all, merely captured by some lightweight strips of wood. There is no deck beam at that location to attach to. See the last photo attached. Surveyor recommended attaching the bulkheads to the deck with a strong epoxy joint for stiffness and strength, but the current arrangement seems so intentional that I wonder if it's designed for the deck to flex. Any thoughts?
     

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