Question about bunks vs. chine "hook" and movement

[Sunbeam]

My 22's trailer came without any sort of side guides, so I'd like to add some. I called up and spoke to Pacific's parts department, because I like the look of their heavy duty side guides, and the parts fellow pointed out something that raised a question: He said that when deciding what size/height parts to order, to keep in mind that there is supposed to be a couple/few inches of clearance between the topsides and the guide boards, or otherwise they can chafe the boat when going down the highway. I see that and understand it. However...

My boat, when trailering, will move to one side (or the other) until the chine "hook" gets to either the port or starboard outer bunk, at which point it can go no further and stops. The distance covered is about 6" total (so in other words, when centered, there is about 3" distance between the outer edge of each outer bunk and the chine hook). The boat trailers fine this way (as there is still just enough clearance from "hard things" on the other side), but of course if I have side guides this "walking" will cause the boat to contact/rub on the side guides, as not recommended. The last thing I want is for side guides to damage the boat, vs. helping it.

I was thinking maybe this side-to-side movement was just par for the course, since I had seen where other folks had made special wedges, etc. to keep it from happening, but when I mentioned this to the fellow at Pacific, he said, "well it sounds like your trailer just needs adjustment." That got me to thinking: Maybe this isn't a given, and maybe it would be good to adjust something so it doesn't happen. So, questions:

Does anyone have a trailer wherein the bunk setup (without special "wedges," etc.) keeps the boat from moving side to side when on the road? I got to thinking that maybe the outer bunks could/should be moved outward to the point where they both contact the inside of the chine "hook," so then there wouldn't be that "walking space" available before the bunk engages the hook on one side or the other. Is there a reason this is not done? (Or maybe most people do have the trailer adjusted that way and it is no problem?)

I can see a possible problem in adjusting my particular trailer to have both of the outer bunks out at the chine hooks (so maybe that's why it wasn't done in the beginning). Not that it couldn't be overcome, but before I tackle whether/how to do so, I wanted to see if anyone does have their trailer set up that way, or if there is a reason not to.

Thanks,
Sunbeam

 

[colobear]

Most people have stern tiedown straps to prevent such side to side movement and comply with traffic laws. Either two short ones from the stern rings mounted on the transom to the trailer or one longer one going across the transom side to side and down to the trailer. Recalling the arrangement you have I don't see how you can get that tight enough to prevent movement.

 

[kennharriet]

I adjusted my bunks so they nest as the trailer raises to the hull as you suggest. The best thing I did was to bolt short wedges to the trailer cross member channel to center the boat when loading. These were made of leftover 2"x 6" Trex board. I lined the inner surface of the Trex with indoor/outdoor carpet attached with 5200 to avoid chaffing. The total cost was the four 5/16" x 2 1/2" stainless bolts to attach the Trex. The boat now centers first time, every time with no more fuss and stays centered will traveling.

 

[Chris]

I do not have side guides or any other mechanism to hold the boat centered. If the trailer is not backed too far into the water...the bunks do a fine job of centering the boat when loading. This is not the place for an interference fit. Going down the road I do get some shifting within the limits of the "chine hooks"...the nature of a flat bottom boat on a trailer...but with appropriate tie downs the boat is not going anywhere. Worked for me for something like 50,000 miles. Side guides and side boards are in the way and can cause problems. But then you know me...less is better!

 

[Sunbeam]

Most people have stern tiedown straps to prevent such side to side movement and comply with traffic laws.

I do have a heavy strap (5,000# or 10,000# rated, I forget) that goes from the trailer frame, up and over the gunwales, and back down to the other side of the trailer frame. I can get it very tight (any tighter and I think it might deform the boat). It holds the boat down really well. However (and I realize I may be missing something), I don't see any way that can (or could) keep the boat from doing what it's doing. I say that because no matter how tight it is, it's either a "square," or a parallelogram to port, or a parallelogram to starboard. And I don't see a way to triangulate it (because the boat is there). Even though I don't have the transom U-bolts, I can't visualize how two straps from where they would be, if I had them, would change that (they wouldn't be a big deal for me to install if they would help). It's possible either that I don't understand the geometry, or that I'm not explaining the movement well enough to give a picture of what I mean. I'll see if I can take and post some photos that would show it better than my words can.

...The best thing I did was to bolt short wedges to the trailer cross member channel to center the boat when loading. These were made of leftover 2"x 6" Trex board. I lined the inner surface of the Trex with indoor/outdoor carpet attached with 5200 to avoid chaffing. The total cost was the four 5/16" x 2 1/2" stainless bolts to attach the Trex. The boat now centers first time, every time with no more fuss and stays centered will traveling.

Thanks for the description. I can't quite "see" it in my mind --I'll see if maybe you have a photo in your album.

Is it the outer bunks (on the chine hook) or the inner ones (on the keel strip) that you have nesting things?

I do not have side guides or any other mechanism to hold the boat centered....Going down the road I do get some shifting within the limits of the "chine hooks"...the nature of a flat bottom boat on a trailer...but with appropriate tie downs the boat is not going anywhere.

Okay, that sounds about how mine is. I was watching some videos about launching retrieving (linked to in the launching thread where I was asking questions), and was visualizing the boat wanting to maybe blow sideways over the fender area when launching or retrieving -- but maybe it won't even be a problem. I just didn't want to find out by putting a bunch of gouges in the boat! I do know it works just fine for actual trailering down the road Maybe I'll get a chance to see your trailer/bunk setup at Powell.

Worked for me for something like 50,000 miles. Side guides and side boards are in the way and can cause problems. But then you know me...less is better!

 

[Sunbeam]

Here are some photos to show what I mean. I should have posted these in the first place to make it clearer, sorry.

Here is an overview of the trailer. Pardon the "ratty" look; this is a photo of the trailer as I first saw it, before I pretty much rebuilt it. Sad looking! (The boat was stored indoors, but the trailer was left outside to fend for itself.) However, even though it has new bunks on it now, I basically duplicated what was there.



Here is the trailer with the boat on it. You can see that on this side, now, the "chine hook" is basically hooked on the bunk. It cannot go any further to port (by the way, my world is not this bleached out - I just played with the exposure to show the bunks more clearly).



The other side, on which there is now 5-6" of space between the outer bunk and the "chine hook." The good thing is that even all the way slid over, there is no interference now. But if I added side guides, there would be.



I can see a couple of possible reasons that the bunks were not pushed outward to engage both chines. One would be that it looks like it might be a bit complicated to do, so they just didn't bother (reason being that since the trailer frame goes up, the bunk would have to go up too, and I can see that one or more bunks might go past their limit of adjustment without some modification). Two would be that there is actually a good reason not to do this, and I just don't know what it is.

Chris: Are you saying this is preferable to having the bunks fit the chines more closely? If I don't get side guides it's not really a problem as long as I know it's not wrong, if you know what I mean.

Kenn: Can you explain your modification another way?

Barry: Do the straps leading forward from the U-bolts to the trailer keep the boat from sliding sideways like I'm showing? My mental geometry is not quite up to that

Thanks,

Sunbeam

 

[nordicstallion]

I used to have a lot of side to side shifting even with straps cinched down tight to the aft corners of the trailer. I never liked the side loading guides as they only gave a general location of center & was always backing back in the water to try again. I removed, shortened , rebent & reinstalled the guide stantions on the inside of the trailer frame so that the carpet covered side boards just made contact below the waterline. Centers every time & no more side to side slip while trailering. Problem solved! Vern

 

[thataway]

Using a set of straps to the U bolts will prevent the boat from moving side to side. The large single strap will not prevent this moving.

It looks as if you have plenty of room on the trailer frame to move the outside bunks slightly further outward so that they line up with the reverse chine.

The side bunks are set about an inch off the side of the boat, so it will not chafe. I have both side bunks and tunnel bunks on my cat--as well as the U bolt straps, and the boat does not move going down the road. The C Dory just has the center bunks, plus side bunks--and a single center strap, as you describe--and the boat does move around, no matter how tight I have the single holed down strap. However, my side bunks are now, and no chafing on the gel coat.

 

[Sunbeam]

It looks as if you have plenty of room on the trailer frame to move the outside bunks slightly further outward so that they line up with the reverse chine.

I think I could probably do it, but I can also see why (assuming it's the preferable way to have them) they were not set that way to begin with. At least I *think* I see it. If you look at the adjusters (under the bunk) for the outer bunks, you can see they are nearly at the lowest setting. But, if I move them outward, the trailer frame goes up, so the bunks would go up. There is a tiny bit of downward adjustment, but I think the frame goes up more than the adjustment range. So okay, I thought, just let that bunk "rise" just as much as it has to, and then raise the center bunks as much as they need to go up to meet the boat again. But then I noticed that the center bunks were adjusted almost as high as they can go (unless I also move them outboard, which I'm not sure whether that is still good support for the boat or not - not much experience with this).

So that left me wondering whether the trailer was adjusted this way because it was "easy," or because there was a good reason. I tend to think it might be the former because of a couple of other "features" it came with (such as the spare being mounted in such a way that the welded eye for the extra bow tie was blocked...).

Although in principle it seems better to have a boat lower on the trailer, it might actually be a feature to have mine just a scoch higher. Reason I say that is the lighter duty Pacific guide ons look perfectly adequate, but because my boat is so close to the trailer frame (heightwise), I couldn't fit them above the rails, and if mounted below they would be rather short and hit the boat at an awkward point on the topsides. If the boat were a couple of inches higher on the trailer, I might be able to fit them. At any rate, I think there are enough factors that I would have to just go ahead and start adjusting, but I figured first I would find out if there was a good reason *not* to have the outer bunks tight to the chine hooks.

On the other, other hand, the trailer tows so beautifully that I'm almost loathe to mess with it (such as raising the boat).

Sunbeam

 

[Foggy]

What I'm looking for on a trailer for my boat are a set of bunks (preferably "split") so that the hull chines rest on the superior edge of each bunk: 2 port, 2 starboard. Easier with a more pronounced "V" hull than flat bottom. This, with tie downs ( 2 stern, 1 over the cockpit, 1 bow) should prevent side "waddle" en route.

I saw a boat in the Keys on asphalt off the trailer once when someone turned a corner at an intersection with no tie downs. The boat broke loose and was off the trailer in the middle of the intersection. This was an unnatural sight and motivated me to avoid this experience.

Oh, split bunks aid a double strap pick up for launching with a double fork lift at a marina if a ramp is too steep or not available.

Aye.

 

[Chris]

Trailer looks well set up to me...wouldn't mess with the bunks. I would add some tie down eyes...probably piggy back them with the light mounts...or the cross member bolts...so that I could use a couple of cam-overs from there to the transom eyes or the aft cleats. You want to hold the boat down on the bunks. Pacific makes a few different eyes in galvanized that would work well.

 

[Sunbeam]

Maybe you're looking for something like this from the 22 "Jenny B"? I believe the split in these bunks is to facilitate sling launching. It's a Pacific brand trailer, which I think would be my choice were I ordering a new one.



I'm not sure if the outer edge of the outer bunks is tight to the chine "hooks" or whether it's more like mine; but besides the split, the bunk set up looks similar to mine overall - although my outer bunks look a bit longer. In this photo you can see the port side is reasonably tight to the chine, but I can't tell for sure if the boat is centered on the trailer or over to one side like mine in the earlier photos. If it is centered, then I think I may be tempted to try moving my outer bunks outward a bit.



Looking at the straps from the U-bolts in this photo, I am not able to tell how they would keep the boat from shifting to one side or the other; however the bunks sure would if they fit like this on both sides :thup

 

[Sunbeam]

Trailer looks well set up to me...wouldn't mess with the bunks. I would add some tie down eyes...

My trailer is connected by welds. It does have a couple of tie-down eyes welded on, but unfortunately they must simply be in a "stock" location, because if I run a strap to them it is too far aft, and so doesn't fit properly over the gunwales. So (for now at least), I tie the strap right around the trailer side frame rails. I think it holds the boat down as well as eyes would, but it doesn't feel all that elegant. I'll check Pacific's parts page, thanks.

PS: Hope to see you at Powell

 

[Chris]

The problem with the over the gunwales thing is that it introduces several feet of tie down...rope...strap..whatever...which translates to excessive stretch. That stretch will allow the boat to lift off the trailer...which will let it move around. The key to a good tie down system is to keep them as short and direct as possible. Look at the tie downs on Don's boat above (same as mine)...very short and direct.

 

[Wefings]

Just cross your tie downs . port eye to stb trailer and vice versa . It wont move .
Marc

 

[Sunbeam]

Just cross your tie downs . port eye to stb trailer and vice versa . It wont move .
Marc

I don't have the U-bolts (yet), but .... would one be able to do that and not foul the engines (or rather the engines foul the lines)? We used to do that with kayak and canoe bows and sterns to the front and rear bumpers (erm... back when cars had those).

Actually, even without interference from the engines I don't think that would work for me as my trailer frame does not extend aft past the boat.

I made a nice trailer-tie down bar for a Whitehall type rowing boat that consisted of a solid (wooden) bar that went across the boat and locked into the oarlocks port and starboard. The ends continued on and extended about 6" past the boat and that's where the tie down lines originated. It was great as it not only held the boat firmly down; but both lines went on an inward angle (so no parallelogram could happen), and neither of them even touched the topsides. Win/win. So far my ideas for something similar on the C-Dory haven't resulted in a fair lead though.

It's great to hear all of your ideas though, and even if a particular one doesn't work for me they may work for other setups.

 

[Foggy]

Maybe you're looking for something like this ..... It's a Pacific brand trailer.....



....split in these bunks is to facilitate sling launching.




......the outer edge of the outer bunks but reasonably tight to the chine......

Nice. That is what I'm talking about. Except, to my eye, another "split" in the bunks forward might be nice for the second strap if proper with the balance point aft.

Crossing stern tie downs is a good idea, if it can be done cleanly, to help prevent side-to-side wobble. Short vertical tie downs keep the craft down on the trailer.

Aye.

 

[colbysmith]

I have the bunk trailer, which I added two more bunks for a total of 4. I trailer a lot and have noticed very little boat movement. What I do notice is the boat usually centering itself if I didn't when loading. I also use a single strap over the back. I think if the trailer, axle and wheels are properly set up and balanced, you shouldn't be getting much boat movement. I also have the single posts, but do like the idea of side boards, even though I've never used them. I agree with Chris's earlier post about proper retrieval of the boat, ie position of bunk trailer in the water. I try to back it in just till where the forward tips of the bunks get wet. But I realize steepness of the ramp will effect how the aft end of the boat lays on the trailer as you pull out. Colby

 

[thataway]

Colby, you just are not driving on rough enough roads! For example the Grapevine on I 5 or I 12 thru Louisiana, and then I found some up in Wi and MI this last summer....

 

[colbysmith]

Oh, I'm on plenty enough rough roads! :-( Those are the ones that center the boat. ;-)