Collective wisdom of hive mind please. And be kind please! Remember 'we don't know what we don't know!' 😁
Arwen is on her new trailer and I have to decide what to do with
these bunk supports to get her to sit correctly and safely. The entire boat
weight during trailering will be all on the keel rollers.
So I'm guessing these bunks just help stop the boat tipping one
way or the other? Should they also be arranged to stop lateral movement of the
hull when on the trailer as well (even though she will be tied on securely
midships and at bow)? 😕
With no engineering nous whatsoever, how should I best orientate
these bunk supports?
1. as they are, running length ways or turning them 90 degrees so
that they run width ways across the hull bottom? And a) if width ways...with the
post lean in towards the skeg or outwards towards next plank chine? And b) the
actual bunk beam with its pivot bolt head
facing forward or facing the stern?
2. keeping them running along length of hull but moving them either
inwards or outwards? And again, if so, a) leaning inwards..or leaning outwards?
And b) the bunk pivot bolt head facing inwards or outwards?
3. moving the entire bunk position so that it is clamped to the outer
part of the trailer 'A' frame near the mudguard and so that it runs lengthways
along the hull and goes under the next plank up, just past the chine join with
the hull bottom boards?
4. Are they correct length if they aren't bearing much weight?
5. Are there any other options with the configuration I have missed?
Similarly, with the keel rollers, I need to move the one with the
side rollers as well - back to its original position at the very rear of the
trailer - because thats where it belongs. But, do I need to (A) put an extra roller
under the wider centre case area to support the centreboard when travelling -
or if I have winched up the centreboard tightly into its case and secured it - (B) do I need to support it beneath at all?
As always, having only ever owned one boat trailer before, I
clearly have no idea!
Any help and guidance much appreciated. The trailer manufacturers
were very helpful but they did warn me that some fiddling around would be
needed to get Arwen secure on the trailer given her bottom configuration.
Sail trimming and trailer setting up - dark arts - dark arts
indeed 😕😁
UPDATE:
After asking for advice on two dinghy cruising Facebook forums, I gained the following useful advice
1. move the bunk supports outwards and also forwards so that they go under the bulkhead at the rear of the centreboard case
2. if possible angle them so that they go up to the next plank up and face slightly inwards - this way they will act as lateral supports
3. leave a 2mm gap between each support and the hull side
4. if possible get longer supports - 750mm and two extra vertical supports and then set up as above
5. try to turn down or tape the ends so that they don't dig into the hull as the boat comes onto the trailer
6. wrap them in foam and also some carpet off cuts
One or two people suggested rotating them 90 degrees and placing them under a bulkhead area in the boat. this was a minority suggestion. The overwhelming view was to lengthen them and add additional uprights forward.
UPDATE 2:
Well when we pushed Arwen along her rollers - the hull hit the mudguards as we expected. A phone call to Admiral trailers and plenty of after sale care reassurance. They always expect issues with every boat trailer outside of a specific class design. They were expecting that there might be an issue but weren't sure.
Two solutions were proffered with a favoured one.
A) spacer bars under each of the keel rollers
B) make up a three layer, 40mm thick, galvanised spacer bar to rest across the top of the axle. The whole trailer frame sits on the axle top - so it and the boat would be raised up by 40mm.
B is the favoured method. Fortunately a neighbour may be able to help. He restores old minis and VW campers and has axle props, trolley jacks and a very impressive tool chest of all sorts of sockets and tools. All being well, if I can persuade him to help, we lift up the main trailer frame with the boat still on it and put it on axles prop stands. We then drop the axle, slide in the spacers and with new U clamps and bolts, clamp it all back together again. The idea is the frame will sit 40mm higher on the axle, giving sufficient clearance over the mudguards.
Watch this space! 😄😟😀
I would strongly recommend a roller under the after portion of the centerboard case. This will let you lower the centerboard down onto it after pulling the boat onto the trailer, DRAMATICALLY reducing the forces on the centerboard, the pivot pin and the uphaul.
ReplyDeleteAs far as the bunks, you probably want those to land on or near the bottom panel / garboard joint. Remember, two curved pieces of plywood meeting at an angle are MUCH stiffer than a single panel (a major benefit of laps and chines).
Otherwise, it looks good! Not losing a wheel going down the road is a bit of a plus...
Putting them under a bulkhead is a great idea. I think either the bulkhead at the aft end of the centercase or the one in the middle of the centercase would work. Either way, I would make sure they are aligned with or outboard of the seat fronts.
ReplyDeleteIn short, you want them under a spot where multiple pieces of plywood intersect, as those are the strongest parts when dealing with point loads.
Best of luck!
Good tips Wayne - thanks. I was heading your way and also advice from various forums said the same thing. a bigger issue has now arisen which is we are not sure that when we push her back - she will clear he mudguards anyway. Ho hum. This buyng new trailer stuff is hard work!
ReplyDeleteI have noticed that the stern easily floats off before the bow comes off the roller. You may need to dunk the trailer a little further, but it may be less of an issue than you fear.
ReplyDeleteIf necessary, you can raise the rollers a bit.
Best of luck!
We were just looking at putting spaces under the rollers actually - we have had to do something similar with the motorhome tow bar so that a bike rack locking handle would engage properly and we suddenly though....oow.....turn the idea 90 degrees and it might work on boat rollers!
ReplyDeleteAppreciate the help - if you have any more ideas keep them coming. Thank you so much for the help.
Looking closer at your video, you probably want the aft roller under the skeg. Would it work to move Arwen aft by about 30-40 cm to put the rear roller about 10cm forward of where the skeg curves up?
ReplyDeleteThis would move Arwen aft, potentially helping with the fender/hull interference. One thing to watch with moving either the boat or the axle is it will impact how much weight the trailer applies to the hitch ball (tongue weight). If moving Arwen aft makes the hitch end of the trailer too light, try moving the axle aft to clean up the balance.
You can also look at moving the roller just aft of the axle forward to about 15cm forward of the aft end of the centercase. This should let you lower the 'toe' of the centerboard onto that roller for travel. Just remember to re-tension the centerboard hoist before launching...
It looks like a very nice trailer. The good news is that it is highly adjustable. The bad news is it needs adjusting...
I look forward to more videos of Arwen in the future. You have a beautiful boat and find beautiful places to sail.
Thanks Wayne. The issue is the length of the drive we have to put Arwen on - its 5.9m and steeply sloping. hence her position on the trailer - if we overhang her more - the whole length doesn't fit and the hitch etc is out over the public pavement. also she is already overhanging and with the OB bracket that is 50cm. The legal limit overhang here is 60cm. The only way I'll get the skeg to sit on the rear most roller is to raise the rollers from the front so she slopes slightly. Hence the adjustable height roller at the front. But then I will need to put spaces under the next rollers to get it sorted again.
ReplyDeleteI am going to move the one roller as you suggest to the other side of the axle. Thats a good idea and I added an extra roller just for that purpose. I moved the axle slightly forward to get the entire boat length to fit onto the drive and to create the correct distance at the front to allow the bowsprit to be kept on permanently.
I is highly adjustable and I'm fine with having to do it - I was expecting it. I suspect we will need to put spacers under the rollers to lift them all so that the boat clears the mudguards although I accept completely your point about the boat lifting when she floats off. And as you previously mentioned, lengthening the support bunks and moving them further outwards would be a good move as well.
Thank you for all your help I really do appreciate it
Steve:
ReplyDeleteMoving the bunks outboard is less critical than exactly where they land. As drawn, the Navigator has a piece of (mostly) flat 9mm plywood as the bottom panel. By itself, this is not terribly strong. The best places to land the bunks is underneath where a vertical piece of plywood intersects the bottom panel.
If you think of a large cardboard box, you can bend or break the cardboard pretty easily in the middle of a side. If you press at a corner, it is massively stronger. Plywood functions in much the same way.
I can think of a number of places that would be adequately strong to handle the bunk loads:
- Underneath one of the bulkheads
- Underneath one of the seat fronts
- Underneath the intersection between a bulkhead, the garboard plank and the bottom panel
- Even better, underneath the intersection between a bulkhead and seat front
The key is to find a part of the boat that has something ABOVE that 9mm plywood to take the loads...
The primary purpose of the bunks is to keep Arwen from tipping to one side or the other. If they can keep her from sliding sideways, that is also helpful, but the tie-downs do a pretty good job of restraining her from sliding.
I would try launching Arwen before deciding to install spacers under the rollers. In general, the lower she sits on the trailer the better she will do on the road.
Based on your constraints, I wouldn't even try to get the boat to rest on the last roller. I would put a roller forward of that to land reasonably close to the aft end of the skeg, but letting the last roller just be there for loading should be fine.
It sounds like you have a pretty good idea of what you are needing to do. Best of luck getting her properly settled onto her new wheels.!
Thanks Wayne.
ReplyDeleteI have a dumb question ...do you think the issue is that the axle unit is not wide enough for the boat? Would a wider axle unit extend the mudguards further out?
Steve:
ReplyDeleteA wider axle would certainly allow the mudguards to be further out. The bigger question is do you need a wider axle? Did Arwen run into the mudguards when you were pulling her onto the trailer? How much narrower are the mudguards than Arwen's widest point at that elevation?
If you are floating her off, her stern will float up as she comes off (imagine lifting her stern off the trailer and leaving her bow as it is). This may give you all the clearance you need.
Problem solved. The company were expecting a slight issue and they will resolve it. They think either spacers under the keel rollers or, their favoured option at the moment, is to make a three layered galvanised spacer bar to lie across the top of the axle which will raise the entire boat trailer frame resting on it up by 40mm. This will then allow the boat to clear the mudguards with no problem. It isn't the first time they have encountered such issues with different types of boats and they have used this solution to great effect and success before.
ReplyDeleteAnd yes, she ran into the mudguards - we tested it this morning. It is literally a cm or so difference which is the issue. As soon as the owner saw the photos he was clear that he didnt want me running the boat and trailer up to him because he was worried a bump in the road would cause the mudguards to hit the plank sides and damage them.
Good customer service and after care.
I really appreciate your help and wisdom Wayne - thanks for all your help and reassurance - deeply appreciated :)
Be sure the trailer is hitched to a vehicle before jacking it (the vehicle keeps it safely anchored at the front).
ReplyDeleteSounds like you found a quality outfit!
Good tip. Thank you
ReplyDelete