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Proper boat positioning on trailer?-gctid401728

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    Proper boat positioning on trailer?-gctid401728

    Long story short. According to the PO, the aluminum I beam tandem axle trailer for my 2455 was ordered and set up specifically for this boat from Classic trailers (now defunct). However although the bunks are properly positioned, I had to move the winch stop as far forward as I could physically move it in order for the transom to rest on the end of the bunks. I've always heard that this is the proper position for the boat to be in when resting on a trailer. This has resulted in two problems. First off, the bow pulpit always contacts the trailer winch when launching or retrieving the boat. This occurs no matter how deep or shallow I position the trailer in the water. I believe that our ramp angle may play a small role in this problem as it fairly steep. Secondly because the boat is now so far forward (in relation to the trailer) my tongue weight is probably in the neighborhood of 300 lbs as I can barely lift the tongue off the ground, although it still tows smoothly and is stable up to 65mph. I feel that the trailer is actually to small for the boat even the literature that came with the boat states that the trailer is suitable for 22' to 24' boats.

    I've tried out many configurations with the trailer winch mount in order to prevent the bow pulpit from hitting the winch and after adding another cross member and a keel roller to keep the bow from dropping as it disengages from the front bunks I *think* I may have hit upon a combination of winch mount modifications and extra support for the bow that might work, but I haven't had time to test them yet.

    Fast forward to this afternoon when I was talking to a sales rep at a marina that sells boat trailers about the problem. The sales rep said that I could have up to a foot of the boat hanging out past the end of the main bunks and it wouldn't hurt the hull even when stored over the winter. I told him what I've always heard about boat positioning on a trailer and he replied that all the trailers that they sold were set up this way.

    So with all that out of the way, where should the boat be positioned on the trailer for the best support?

    #2
    it's just my opinion and I have no scientific study to prove it.... The bunks should be under the transom (support it) as the transom is the strongest part and won't deform. It also carries most of the weight of the engine.

    I don't know how your bunks are attached. My (OK, a lot smaller) trailer has the bunks mounted to a full length of angle iron which then is mounted to the trailer supports.

    If my boat would need "extended bunks" I would just get longer pieces of that steel and let the bunks extend a bit further back. Replace steel with aluminum for your trailer...

    I'm sure people will tell you that you need 10% tongue weight and with the size of your boat this is most likely above 300lbs but I never understood this for a well designed trailer. I had a 3500lbs utility trailer which, fully loaded, was fine with around 60-70lbs tongue weight. Wouldn't try this with my 3000lbs boat trailer with its outdated stage coach suspension, it needs ~150lbs but that's still 5%.

    Take a bathroom scale with sufficient capacity, put a block of wood on it to just have the coupler level and let it rest on it. You got your tongue weight. Better than guessing.

    Every vehicle mainly brakes with the front axle and if you load the rear you lift the front unless you have a level control system.

    Comment


      #3
      kjs wrote:
      it's just my opinion and I have no scientific study to prove it.... The bunks should be under the transom (support it) ..... (snipped)
      +1

      rule of thumb:

      single axle - set up so 10% of the total (loaded) trailer weight as tongue weight

      tandem axle - set up so 5% of the total (loaded) trailer weight as tongue weight

      Weigh your boat at a dump, commercial scale (look for a concrete plant), or highway weigh scale.

      Remember that on most trailers, the axle (assembly) will slide up and down the trailer frame to accommodate.

      Use a tape measure to assure you're square

      Use a bathroom scale under the tongue (do this when when the Admiral is away)
      ________________
      1989 Bayliner 3270

      Comment


        #4
        My understanding is the pointy end goes toward the car. Beyond that I know little about trailering.
        Jim McNeely
        New Hope a 2004 Bayliner 305 Sunbridge Express Cruiser
        Twin 5.7s with Bravo2 drives
        Brighton, Michigan USA
        MMSI # 367393410

        Comment


          #5
          Nikko wrote:
          Use a bathroom scale under the tongue (do this when when the Admiral is away)
          I use a different method: I ask her to bring it to the trailer as safety requires that it's loaded right. Voila, no complains and even help.......

          Honey, you know, with he kids in the car I don't wanna go a risk.

          Comment


            #6
            Wingnutt wrote:
            Long story short. According to the PO, the aluminum I beam tandem axle trailer for my 2455 was ordered and set up specifically for this boat from Classic trailers (now defunct). However although the bunks are properly positioned, I had to move the winch stop as far forward as I could physically move it in order for the transom to rest on the end of the bunks. I've always heard that this is the proper position for the boat to be in when resting on a trailer. This has resulted in two problems. First off, the bow pulpit always contacts the trailer winch when launching or retrieving the boat. This occurs no matter how deep or shallow I position the trailer in the water. I believe that our ramp angle may play a small role in this problem as it fairly steep. Secondly because the boat is now so far forward (in relation to the trailer) my tongue weight is probably in the neighborhood of 300 lbs as I can barely lift the tongue off the ground, although it still tows smoothly and is stable up to 65mph. I feel that the trailer is actually to small for the boat even the literature that came with the boat states that the trailer is suitable for 22' to 24' boats.
            First, I also believe that the bunks should go to the transom.

            Regarding the pulpit, the winch may need to be lowered on the winch post, or you need to back in farther. You also need to realize knowing how far to back the trailer in for each ramp is 95% of the game.

            You NEED tongue weight for everything to tow properly. If you were under 300 lbs tongue weight, you were NOT loaded properly before. You need to ensure the boat is sufficiently forward on the trailer, and move the axles if necessary and adjustable. With low, neutral or even negative tongue weight, the boat and trailer ends up pushing the rear end of the tow vehicle around which is VERY bad in an emergency (hit brakes and you can easily jack-knife), and this will easily contribute to a poor towing experience and excessive stress on everything. At the 5% rule with fuel, you should have about 430 lbs of tongue weight minimum... at 10% you're closer to 700 lbs or more of tongue weight.

            I believe that a modern 24' max trailer would likely be small for an 80s Bayliner, but it should still work. Remember when the boat was built they did not include swim platforms or bow pulpits in the length, which they now do... so a 24' boat from 1988 is larger than a 24' boat from 2008, just as published horsepower figures have changed over the years.


            I've tried out many configurations with the trailer winch mount in order to prevent the bow pulpit from hitting the winch and after adding another cross member and a keel roller to keep the bow from dropping as it disengages from the front bunks I *think* I may have hit upon a combination of winch mount modifications and extra support for the bow that might work, but I haven't had time to test them yet.

            Fast forward to this afternoon when I was talking to a sales rep at a marina that sells boat trailers about the problem. The sales rep said that I could have up to a foot of the boat hanging out past the end of the main bunks and it wouldn't hurt the hull even when stored over the winter. I told him what I've always heard about boat positioning on a trailer and he replied that all the trailers that they sold were set up this way.

            So with all that out of the way, where should the boat be positioned on the trailer for the best support?
            Are the bunks adjustable or fixed? Are the fenders adjustable? (I assume so, since an aluminum trailer.)

            If the bunks alone provide adequate support to the bottom of the boat, I would start by moving the winch post all the way forward. Load the boat on the trailer so that the transom is at the end of the bunks. Bring the boat up on land with the winch line on the bow eye for safety, but the winch post/bow rest not necessarily touching the bow. The weight of the boat should sit level on the bunks, so that the full bunk length is fully supporting the hull. The winch post does not need to support the weight of the boat at rest.

            Once you are on level land, move the winch post and adjust the winch so that you can secure the bow eye and that when you winch, the winch line is somewhat level to the bow eye. If the winch is higher than the bow eye, you may pull the boats bow "up" which will position it too far forward on the trailer, and the boat may rest crooked so that the aft end is on the bunks, but the front end is "floating" and resting on the bow eye.

            If it's too low, it will pull the bow down, which will make loading difficult.

            Steep ramps may require you to back farther in to the water to clear the winch post. The boat should not be completely floating, but you should also not use the winch to drag the heavy boat up the bunks. It's backing in the right amount for each ramp incline which is 95% of the task IMO.

            Comment


              #7
              Your thoughts are correct, transom at the end of the bunks. For boat trailers, tongue weight should be 7-10 % of total boat and trailer weight. Your trailer might be a bit short, but a steep ramp angle will ALWAYS cause the problem you are having. Finally, that salesman is full of $chitt...
              Jeff & Tara (And Ginger too)
              Lake Havasu City, AZ
              |
              Current: 2008 Playcraft 2400 MCM 350 Mag B3
              2000 Bayliner 3388 Cummins 4bta 250s (SOLD 2020)
              2000 Bayliner 2858 MCM 7.4 MPI B3 (SOLD 2018)
              2007 Bayliner 305 MCM twin 350 Mag B3s (SOLD 2012)
              2008 Bayliner 289 MCM 350 Mag Sea Core B3 (SOLD 2009)
              And 12 others...
              In memory of Shadow, the best boat dog ever. Rest in peace, girl. 7-2-10

              Comment


                #8
                We just went through this ourselves - transom needs to be supported within a couple of inches of the stern.

                You need bunks back there at the transom and those bunks need to be supported as well - not 12 inches away but near the transom.

                Is the trailer rated for sufficient weight for this load?

                Hope this helps
                Northport NY

                Comment


                  #9
                  I never thought about this but it's related I guess.

                  My trailer just has rollers (ez loader). Where should the farthest aft rollers be in relation to the transom? After reading this thread, can I assume they should probably be pretty close to under the transom?
                  Aquatic Muse
                  Mount Vernon, WA
                  MMSI: 367498870
                  '79 Bayliner Santiago w/ Mercruiser 470 power and drive

                  Comment


                    #10
                    Mileskb wrote:
                    I never thought about this but it's related I guess.

                    My trailer just has rollers (ez loader). Where should the farthest aft rollers be in relation to the transom? After reading this thread, can I assume they should probably be pretty close to under the transom?
                    ideally the center of the rearmost roller should be under the transom. If you look at your transom from the inside there's fiberglass going further forward (butt filling). It should sit in this range. If you draw a force diagram you will see that a bit further forward can still handle a bunch of load so you don't have to get religious about it. Depending on boat size up to 2" won't kill your bottom.

                    Comment


                      #11
                      Mileskb wrote:
                      I never thought about this but it's related I guess.

                      My trailer just has rollers (ez loader). Where should the farthest aft rollers be in relation to the transom? After reading this thread, can I assume they should probably be pretty close to under the transom?
                      Yep. And for rollers it's even more important as they provide "point loading" vs the "distributed loading" a bunk will provide.

                      EDIT: Probably should have added one more thing to this...if the rollers or bunks lie directly under the boat's stringers when the boat's loaded on the trailer, it's not as vital to have them also positioned to support the transom directly. It's not bad to do this - but the boat load will be handled by the stringers (assuming they're in good shape) and transferred to the transom (assuming a structural bond between stringer and transom).

                      I had a small 14' runabout a while back that was stored incorrectly on a trailer for years with the rollers (and then bunks) stopping short of the transom buy about a foot. It developed one heck of a hook in the hull that showed itself as some really spooky handling - never could get that hook out, so I sold the boat.
                      ________________
                      1989 Bayliner 3270

                      Comment


                        #12
                        Nikko wrote:
                        Yep. And for rollers it's even more important as they provide "point loading" vs the "distributed loading" a bunk will provide.
                        Thanks Nikko. I actually created another thread in the tech area, then went out and moved the winch tower about 13" forward. Mind you the rear rollers have been about 12" from the transom edge for 30+ years now, but thankfully in checking with a straight edge, all seems fine. The rollers now sit about an inch in from the edge. Until I actually do a recovery I didn't want to cut it too close as the rear of the roller of course is past the edge of the transom. I think it helped that although the rollers were pretty far forward for so long, that put the rear set of rollers on that assembly under the engine mount and the forward rollers of that assembly under the gas tank. I don't think that was planned by the previous owner, but it worked out I guess. It certainly looks more proper now and it's obvious the weight is distributed better. I guess being an older boat with a wood core saved the bacon a little. The transom itself is 2" thick and of course as you mentioned, the edge is even thicker so the rollers now are right in the middle of it.

                        I'm so glad I ran across this thread. All the people that worked on this boat, not to mention the previous two owners... no one noticed this. FWIW it's a '79 Santiago.
                        Aquatic Muse
                        Mount Vernon, WA
                        MMSI: 367498870
                        '79 Bayliner Santiago w/ Mercruiser 470 power and drive

                        Comment


                          #13
                          jeffw wrote:
                          For boat trailers, tongue weight should be 7-10 % of total boat and trailer weight.
                          This is a rule of thumb to make the worst designed and build trailer handle OK or in other words to put lipstick on a pig. It also depends on the type of vehicle you want to tow with. With the typical truck it is good as they usually don't have sufficient weight on the rear axle and are designed for a good load. It also applies to the older style SUV's build on truck frames.

                          If you go to the newer unibody SUV's and even worse for cross-overs (like I have) with front wheel drive you do not want weight in the rear. You will need a well designed trailer where the axle is perfectly square to the tongue (impossible with a sliding leaf stage coach axle or the equalizing tandems as they will move back and forth under load changes) and the longest feasible tongue. I was lucky with my trailer that the leaf springs are attached on both sides which makes them wander only a tiny and acceptable bit. Saved me the money importing a rubber torsion axle from Europe as the ones sold here with 6" of torsion arm are crap (side note: even a large EU manufacturer sells the right ones in Europe, 8-10" and 6" crap here).

                          Surprisingly the axle was only off by 1/8" from square which I was able to correct with the axle mounting plates. Originally the boat was set into a position where I had 220lbs tongue weight (~7% of the ~3000lbs total) and my vehicle handled pretty poorly with everything/everyone in the trunk and seats. After the axle work was done I lowered tongue weight to 100lbs (3%) and it handled just as it should.To have the transom still sit on the bunks I increased it to 145lbs (~4.8%) but I'm not sure that I leave it there as the thing handled better at the lower load. When I replace the bunks with plastic lumber made 2" longer I'm sure I will move the boat a tad back again to get ~4% or 120lbs.

                          When you try this at home make sure you have the tank of the boat full as you don't want to go to low and when you throw stuff into the boat try to load it over the axle or distribute it equally on both sides.

                          Comment


                            #14
                            kjs wrote:
                            This is a rule of thumb to make the worst designed and build trailer handle OK or in other words to put lipstick on a pig. It also depends on the type of vehicle you want to tow with. With the typical truck it is good as they usually don't have sufficient weight on the rear axle and are designed for a good load. It also applies to the older style SUV's build on truck frames.

                            If you go to the newer unibody SUV's and even worse for cross-overs (like I have) with front wheel drive you do not want weight in the rear. You will need a well designed trailer where the axle is perfectly square to the tongue (impossible with a sliding leaf stage coach axle or the equalizing tandems as they will move back and forth under load changes) and the longest feasible tongue. I was lucky with my trailer that the leaf springs are attached on both sides which makes them wander only a tiny and acceptable bit. Saved me the money importing a rubber torsion axle from Europe as the ones sold here with 6" of torsion arm are crap (side note: even a large EU manufacturer sells the right ones in Europe, 8-10" and 6" crap here).

                            Surprisingly the axle was only off by 1/8" from square which I was able to correct with the axle mounting plates. Originally the boat was set into a position where I had 220lbs tongue weight (~7% of the ~3000lbs total) and my vehicle handled pretty poorly with everything/everyone in the trunk and seats. After the axle work was done I lowered tongue weight to 100lbs (3%) and it handled just as it should.To have the transom still sit on the bunks I increased it to 145lbs (~4.8%) but I'm not sure that I leave it there as the thing handled better at the lower load. When I replace the bunks with plastic lumber made 2" longer I'm sure I will move the boat a tad back again to get ~4% or 120lbs.

                            When you try this at home make sure you have the tank of the boat full as you don't want to go to low and when you throw stuff into the boat try to load it over the axle or distribute it equally on both sides.
                            Not sure I agree with going quite this lightly loaded on the tongue - but if it works for you...

                            Just for giggles I popped onto the EZlLoader site to see if they had any words of whit. Scroll down to the top left of page 14: http://"http://www.ezloader.com/Manu...s%20Manual.pdf

                            Also found some good info on the Shoreland'r site: http://"http://www.shorelandr.com/pa...pf_trstep3.htm
                            ________________
                            1989 Bayliner 3270

                            Comment


                              #15
                              well, then go to any European site and look there. The difference is that there the loads are mandatory for minimum and the max tongue load of the VEHICLE is specified and you get a ticket if you exceed it. Normal vehicle max load is 50kg or 110lbs, 75kg are only a few and the highest rated 100kg are very rare and exotic. The difference is that the trailers also have to be type approved and they check how well they are designed (trust me, I know. My uncle had a trailer manufacturing business there).

                              I'm fully aware of the recommendations here and as I said: lipstick on a pig.

                              Comment

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