basic beginner questions about boat trailers (specifically with aluminum boats)

[jimmwaller]

hello all,

I am realizing that I need to start thinking about replacing some parts of my trailer, and I've never really thought about my trailer too much until now. So I have some basic questions, hopefully someone can get me pointed in the right direction!

1) just a general question about trailering aluminum boats. I have an old starcraft islander, and there are strakes riveted on. As i was going through the towing and trailers forum here looking for answers, I read conflicting things about whether the weight should rest on the strakes, or just on the hull. Can anyone clarify?

2) Another general boat trailering question: right now, I have keel rollers in the center, and wooden/carpet bunks on the sides. Where should the weight be resting at a complete stop, on flat ground—on the bunks, or on the center rollers? I had always figured that most of the weight should be on the center rollers with the bunks just BARELY touching for stability, but now that I'm looking at my setup closer, it seems that the weight is entirely on the bunks. The rollers help the keel move along the trailer up until the last few inches, and then the bunks are such that the boat gets pulled up and off the rollers just a little. Is this proper? I assumed everything was set up properly because the P.O. of my boat seemed to be really knowledgable and careful, but who knows.

3. My wooden bunks are falling apart. Is it best to just bolt on new ones and call it a day? It sure looks like the bunks are held on by brackets, which are attached to the trailer via square U-bolts. The U bolts and brackets are also rusty, so maybe I should just replace everything... take it down to the frame and keel rollers and start from scratch. But I'm worried about getting the right stuff. Is there some way that I can take a measurement or something to make sure I get the right bunks/brackets? Or brackets that are adjustable?


Thanks, really appreciate the insights!

 

[Scott Danforth]

never rest on strakes

weight on bunks, rollers to help guide on boat.

buy new bunk wood, brackets as needed. carpet is cheap. DO NOT USE TREATED WOOD WITH ALUMINUM BOATS. stop at your local trailer store - they can help.

 

[jimmwaller]

Hi Scott, thank you for your reply.

So just for my own clarification and peace of mind: It's totally normal for a ~22ish foot aluminum boat to be totally supported by two ~10 foot 2x4s with carpet on it? And those 2x4s should just go right under the hull and rest on a pretty wide sheet of aluminum?

(trying to figure out a way to type this without sounding like I'm coming across as saying that what you're telling me sounds stupid. For the record, this is not the first time you've helped me on this forums and I have nothing but respect for your thoughts and appreciate your input... in this case, I'm just trying to "type it as stupid as possible" just to make sure that even the "dumbest" version of what I'm understanding is acceptable! Just couldn't find a different way to type it, ha. But just wanted to clarify that I'm the idiot here )

I have been looking around west marine online and trying to find more adjustable brackets, because I'd like to set things up to be further apart to keep them away from the strakes in light of what you're saying. But I'm only really seeing fixed brackets, are adjustable ones called something special? I've just been typing "bunk brackets"....

 

[Scott Danforth]

most bunks are heavier than 2x4. my boat uses 4x6's.

my searay was 2x6 white oak

 

[jimmwaller]

hm interesting. Mine are definitely 2x4, this might explain why they're falling apart.

Guess the first step is to upgrade to some thicker bunks.... ha

 

[roscoe]

A few 2x6, carpet, glue/stales, a few of these brackets from tie down engineering.

 

[M2HB]

I agree with a boat of that size should have 4 - 2x6 bunks for the bottom of the hull.

I also recommend good 2x6 side rails.

I use Stoltz self centering keep rollers with stainless steel shafts. They will last a long time. A lot of the problem with keel rollers is the carbon steel shafts rusting inside the rollers.

 

[JimS123]

1. On a new setup I would mount the bunks just outboard of the outer strakes. That will help guide the boat on the trailer and have it end up where its supposed to be.
2. Your idea is correct. Weight on the rollers, bunks for stability. The keel is the strongest part of your hull. Stoltz rollers are the best, with the self centering ones even better.
3. Is your trailer rated for the correct weight capacity and length of your boat? If so, just replace the bunk boards in like kind. Are the brackets and U-bolts so rusty that their strength is compromised? Then replace all of the parts. If just surface rust, leave everything as is because if you try to loosen the nuts the bolts may break. Replace whatever fastener was used to attach the wood to the brackets. Use marine carpet with SS staples on the bottom. Use douglas fir or oak or any substantial wood. Don't use common SPF stud grade. Don't add EZ Slides as they don't work well on aluminum hulls.

 

[Lightwin 3]

Definitely 2 X 6 with brackets like above. You'll need new U bolts.

Also, the bunks should extend aboüt 1/2 to 1" beyond the transom.

Lot's of commercial "side guides"available. Those help greatly in centering the boat on the trailer.

 

[jimmwaller]

Hi all,
Thanks for all the good info. I'm getting somewhat conflicting information about where the weight is supposed to rest.... is the weight supposed to go on the keels on the rollers, or on the bunks?

I'll look into the products mentioned, thanks for the leads! Will definitely have more questions later, ha.

 

[roscoe]

Many trailers have no keel rollers, all the weight is on the bunks.
In my opinion, keel rollers are those things, those darned nasty things, that I have to lift the keel onto after the boat gets turned wonky while loading.

For me, there are all roller trailers,
and bunk only trailers.

 

[M2HB]

Between self centering rollers and side rails, loading the boat shouldn't be a problem.

 

[JimS123]

Hi all,
Thanks for all the good info. I'm getting somewhat conflicting information about where the weight is supposed to rest.... is the weight supposed to go on the keels on the rollers, or on the bunks?

I'll look into the products mentioned, thanks for the leads! Will definitely have more questions later, ha.

Your trailer is designed like most all were back in the 1950's and 60's. Those were the golden years of trailer boating, when people actually read books. Back then trailers came with an instruction manual specifying how to set it up. Ideally, you want to launch a boat with merely a push with one finger, but the hull needs to be properly supported as well.

If you think you want to rest the weight on the bunks, you might as well remove the rollers. That's be cheap. However, then you might want to add a couple more bunks so you don't rest all the weight on one spot of the light tin hull. Adjusting the bunks under the strakes will solve that problem, but then launching will be a problem.

 

[Lightwin 3]

I haven't owned a trailer in years with center keel rollers. Only two or four bunks.

 

[JimS123]

I haven't owned a trailer in years with center keel rollers. Only two or four bunks.

Well, I haven't "bought" one in years....

My 1968 Gator is still the classic design, plus I have a recent Load Rite and a Karavan that were "converted" by adding Stolz self-centerers on EACH crossmember.

 

[Lightwin 3]

Funny, I was thinking of "Gator" trailers when I wrote that.

My bunk trailers have, typically, had one center roller on the back cross member. Somewhat useful for alignment but very useful for an outboard trailering support.

 

[Doh]

I bought one last year, and an Aluminum Boat sitting on it. It sits entirely on the Bunks, (not the only roller on the front.)

The Bunks should be Center of the Hull, 1/2" from the Strake (either Side) Starcrafts are famous for Rib Cracks, where the bottom ribs do not extend far enough out to the sides, so support the boat where the braces are.

Adjust the height of the Bunks so you have at least 1" clearance of fenders and cross braces.

Bunks should be 2/3rd's the OAL of the Boat. Flush to the Transom.

Slides were STD Equipment on my New Trailer for an New Aluminum Boat. 6, 6" plastic slides per side.

My 20', 3100lb Easy Loader, has 2x4 Bunks, 2x6" would be better if your brackets allow.

 

[jimmwaller]

Hi,
thank you all for all the great information so far. A couple more questions:

I found a supplier of the brackets mentioned. I am planning to put in four bunks, but:

1) is there a recommended way to "distribute" the bunks? I walked around the boat yard yesterday and saw a few trailers with two long bunks, and a few with four equally sized bunks, and a few with long bunks in the back and shorter ones in the front... etc. How can I determine which setup is right for me? I'm thinking like longer in the rear, shorter in the front, but I have no idea why I'm leaning that way. I just sort of intuitively assume that the stern is heavier...

2) The brackets (tie down engineering) are sold in sets of two... but how many do I need per bunk? I couldn't find any info on weight limits, etc. Do I need three for longer stern bunks? or just two?

3) What about bunk placement? Doh, would you mind expanding on this bit about rib cracks? I just want to clarify, you're saying that the ribs are basically where the strakes are, so I ONLY want to support this boat within... I'm guessing for a 2X6, that's probably 5.5" of wood, plus the 1/2" of clearance from the strake.... so you're saying that I should never support the boat more than 6" from the strakes? Really good to know.

Anything else I should know before I order all these supplies and put on new bunks? It seems pretty straightforward (launch boat, take off old bunks, bolt on new bunks, and probably do a good bit of adjusting right at the boat ramp), but is it really this straightforward in actual practice?

i.e. now that I'm thinking about it, how do I make sure the bunks are aligned properly without the boat being on the trailer, which it can't be without bunks?

Thanks all!

 

[Lightwin 3]

Hi,
thank you all for all the great information so far. A couple more questions:

I found a supplier of the brackets mentioned. I am planning to put in four bunks, but:

1) is there a recommended way to "distribute" the bunks? I walked around the boat yard yesterday and saw a few trailers with two long bunks, and a few with four equally sized bunks, and a few with long bunks in the back and shorter ones in the front... etc. How can I determine which setup is right for me? I'm thinking like longer in the rear, shorter in the front, but I have no idea why I'm leaning that way. I just sort of intuitively assume that the stern is heavier...

2) The brackets (tie down engineering) are sold in sets of two... but how many do I need per bunk? I couldn't find any info on weight limits, etc. Do I need three for longer stern bunks? or just two?

3) What about bunk placement? Doh, would you mind expanding on this bit about rib cracks? I just want to clarify, you're saying that the ribs are basically where the strakes are, so I ONLY want to support this boat within... I'm guessing for a 2X6, that's probably 5.5" of wood, plus the 1/2" of clearance from the strake.... so you're saying that I should never support the boat more than 6" from the strakes? Really good to know.

Anything else I should know before I order all these supplies and put on new bunks? It seems pretty straightforward (launch boat, take off old bunks, bolt on new bunks, and probably do a good bit of adjusting right at the boat ramp), but is it really this straightforward in actual practice?

i.e. now that I'm thinking about it, how do I make sure the bunks are aligned properly without the boat being on the trailer, which it can't be without bunks?

Thanks all!

1. If going 2 X 6, one long is enough.

2. How many cross members do you have. You need a set for each one.

3. Place close to the midle between the keel and chine. More toward the chine.

 

[JimS123]

Its being overthunk. If the trailer were originally designed to carry the size and weight, then why reinvent the wheel? Does your bottom have dents, rockers or hooks? If not, that old trailer has done its job all along.