Steel Boat Building

Discussion in 'Metal Boat Building' started by alaskatrawler, Aug 17, 2005.

  1. alaskatrawler

    alaskatrawler Previous Member

    As a new member of this list I hope I can contribute my experience in building a steel boat to anyone who shares the same desire or needs info on the many steps involved in such an endeavour.

    I have for the last 3 1/2 years been building a 52 foot steel trawler. I easily have one more year of work to finish it. I have been working on it full time essentially 10 hours a day and most every day of the week. Exept for the interior woodworking phase when I hired a shipwright to do the cabinetry and during the hull plating when I hired a couple welders, I have done all the work.
    I have read most of the posts to this list regarding steel boat building and have learned from many of the posts. I can say this that I truly can understand first hand why so many of these projects never get completed. When I started this boat I had no idea how mush time it would consume and cost. It seems everything takes so much longer than you think and the costs keep mounting.

    At this time I am sandblasting the hull myself with one helper. I do not trust any of the commercial sandblast outfits in this area to do the blasting as it seems that they just don't take the time to do it right in this very critical first step toward the final paint job. After the blasting I will hire out the fairing and painting. While that is being done I will finish getting the boat operable and try to launch sometime in November or eary December. I have a website for those that may be interested in seeing the boat and some of the construction photos www.alaskatrawler.com. I have not updated the website in at least a year as I hvae been to busy but when I get her to water and can relax a bit I will post much more photos.
     
  2. JimCooper
    Joined: Feb 2005
    Posts: 81
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    Location: Varies, Aberdeen

    JimCooper Junior Member

    Hello
    Welcome

    You are a bit late to build a trawler, I just retired and I reckon we got all the fish !
    Its funny but I have seen 60 foot steel yachts launched less that 16 months from start to finish with a nice fitout to boot.
    I also have in my neighbourhood one 50 footer that he has been working on for 15 years ! big thing seems to be budgeting for some help in the time consuming areas, and perhaps not being too fussy while being functional.

    Keep the access to your hull inside the backs of cupboards and behind linings. I just pulled out too much of the Salon in my boat to treat the inside of the hull.

    All the best
    Jim
     
  3. alaskatrawler

    alaskatrawler Previous Member

    Hello Jim

    Since this is the first boat I have built I expect I have probably redone it a couple of times over. I spent alot of time on the interior doing mockups to get the spaces fitted out just right.The vessel itself is based on a seiner hull with a yacht style saloon and pilot house.
    I have also been working on an ever tightening budget so can't throw alot of hired help at it. This past week I along with a helper have been sandblasting and priming the boat and should be all done by next weekend. From there I have a painting and fairing crew lined up and ready to start putting the finish on.
    You mentioned leave lots of access behind cupboards..... I have resonably good access to most bilge area but opted to foam the entire inside of the hull so as to forever seal out moisture from the frames. To some this is controversial but I am a believer in the use of urethane foam to coat all the inside steel (except in the engine room). I went a step beyond just foam, after the foam was sprayed , I shaped it to the hull and then had it sprayed with a heavy coating of polyshield. This coating makes the foam as hard a fiberglass on top and seals any chane of water sitting directly on the foam itself.
    I have a freind who has built 6 boats and can usually finish a 60 footer with a more commercial grade interior in around 19 to 20 months. To put a high end interior in a vessel can take significantly longer. I can say the interior work on this vessel amounts to probably 4500 man hours.
    By the way when you pulled out the walls of your salon what did you have to do to treat the inside of the hull? I am curious to know. Also what type of boat do you have

    Best Regards
    Dan walsh
     
  4. JimCooper
    Joined: Feb 2005
    Posts: 81
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    Location: Varies, Aberdeen

    JimCooper Junior Member

    Hello Dan

    I could see the rust on the strakes and tank tops thru the gaps they had left and once you pull off a wee bit you can see more rust so on you go untill you decide you may as well start afresh and rip the lot out and re-build properly. What a way to spend summer ! Actually it's quite enjoyable to have a good project when you have retired.

    I recently bought a 60 foot motorsailer sturdily built by Dutchmen in a German yard 30 years ago, but fitted out too tightly. Everything seems to have something else that has to be removed before it can be removed.

    I have seen some fires from the foam you talk of and I am a little shy of the fumes these materials give off seemingly forever. But I suppose your paint covering will sort that.

    After years at sea I am retired, I have to admit the cold goes to my bones these days in the northern winter so along with the birds I head south for winter. When I'm too old to take the helm I'll have to decide where to die and I suppose a Kirk in Scotland will have to have my bones but I think I have 15 years yet. Morbid but practical ! Is your trawler a "trawler yacht " or a workboat?

    Cheers
    Jim
     
  5. alaskatrawler

    alaskatrawler Previous Member

    Hello Jim

    What are you treating the rust with? If you don't want to use foam have you ever considered ospho? It is an acid based rust killer that really does seem to work. I wouldn't use it on the outside of the hull but for treating rust on the inside of the vessel it would be my choice if I did not want to use foam. I am not too worried about the fire danger of foam, but can understand the issue throughly.
    When I started building this boat I researched the pros and cons of foam versus other insulating materials and the pros outweighed the cons. I was more concerned with moisture somehow getting in between the foam and the steel. So before spraying the steel with foam I blasted the steel to sp-6 and put on a heavy coating of epoxy paint then went over that with foam.
    It sounds like you are enjoying your project and I wish you the best. I look forward to the day when I launch my boat and can finally call and end to the project at least for awhile. By the way my boat is built on a commercial hull but is a pleasure yacht.

    Dan
     
  6. JimCooper
    Joined: Feb 2005
    Posts: 81
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    Location: Varies, Aberdeen

    JimCooper Junior Member

    Dan
    I was treating the rust by grinding and chipping and wire brushing it to bare metal then using an air drying epoxy with "Killrust" written on the tin.
    Sounds like you will have a nice snug hull.

    Have ye a decent engine yet?

    Cheers
    Jim
     
  7. alaskatrawler

    alaskatrawler Previous Member

    Hi Jim

    Wow that sounds like a lot of work....almost as much work as sandblasting. What brand is the epoxy paint that your using that kills rust? Must have rust inhibitors in it. I know interlux has some that are "rust tolerant" to a point.

    As for the engine I have installed it is a cat 3306. Produces 250 hp. have a 4:1 ZF Gear coupled to a 5 blade wheel.

    Regards
    Dan
     
  8. Paul Mooney
    Joined: Oct 2004
    Posts: 8
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    Location: Michigan

    Paul Mooney Junior Member

    sandblasting is best

    I would recommend sandblasting both inside and out as the ONLY way to prepare steel for paint. The inside can be done as pre-blasted and primed provided you are building inside or getting the job done in a reasonable time frame. I go for a 100% white blast with course silica sand for the rough profile it gives. Check out my paint spec at www.fairmetalboats.com/coatings I just surveyed a 65 schooner I launched in 1979, still has the original paint job as the base. I have never seen the acid-converters hold up any where near as long.
    Good luck and happy building
     
  9. alaskatrawler

    alaskatrawler Previous Member

    Hello Paul

    thanks for the recommendation. I did sand blast both inside and out however since I was going to use foam on the inside of the hull I blasted the lower hull portion to near white and then coated with a heavy coat of epoxy. The upper house I essentially brush blasted to clean the steel and then went over the bare steel with foam. This is done a fair bit around here with good success. The steel on my vessel was not wheel abraded so had to do it the old fashioned way. I used coal slag in a variable mix (16-30) which gave a very rough profile when first used and a lesser when used the second time around. I have been told that a real rough profile is not always the best do to the fact that grains of abrasive can become embedded in the profile and eventually loosen from the paint coating. As for acid converters I will agree with you as it is not the best way to treat rust.... blasting is the best. But if you cannot blast and have to use another method to deal with rust especially on inside framing it seems an acid type converter would be the sensible way to go

    regards
    Dan
     

  10. MikeJohns
    Joined: Aug 2004
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    Location: Australia

    MikeJohns Senior Member

    Dan

    I am not a fan of the rust converters, better to remove mechanically. For the Interior you will find that a rotary wire brushing ( angle grinder with a cup or wheel brush) wiped down with a solvent then painted with a zinc rich primer topcoated with epoxy will last well. Sanding disks also prepare the interior surface quite well. However it really depends on the type of corrosion , if it is pitted then you will need to chip or grind out all the corrosion products for an adequate prep. If you have deep pits then MIG them out. The wire brushing/sanding will only work on a uniforn surface corrosion.
     
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