Adding keel ballast

[Robertsfeet25]

Hi all, wanted some advice on adding ballast to my Roberts adventure 25 which has a fin keel. I've noticed that the boat sits very light in the water and has a lot of freeboard, which subsequently makes her a little unsteady in the water. even in relatively light wind and sailing with just a small headsail she leans quite far over making her hard to point close to the wind when beating, and just uncomfortable when reaching, I'm also not getting the speeds I'd like when reaching, (supposedly the fastest point of sailing). it also makes it hard to steer as the rudder feels less responsive. my other problem is she gets pushed around a lot by currents and wind when docking, I can only liken it to being in a dingy.

my thoughts are that if I add some lead weight to the keel I may be able to rectify some of these issues by keeping her more upright when sailing and making her less susceptible to the elements. The Roberts were more made for comfort rather than speed but still, I'd like her to be a little more seaworthy when in stronger conditions.

how much weight could I add? according to specs she's only around 2 - 2.5 ton and I'm not sure how much would be appropriate, if appropriate at all. my thoughts are to bolt two ingots to the tip of the keel and fibreglass around them to make them more hydrodynamic. Any input would be greatly appreciated.

cheers!

[Orion Jim]

Any room to add that ballast in the bilge? Essentially a proof of concept to ensure you are not going to add too much or too little before considering modifying the keel. The difference in righting moment would be slight, but improved, if the weight was lower.

[Fore and Aft]

Robertsfeet25, this will probably get me flogged but you never buy a Roberts 25 (Or any Roberts) for sailing ability. The 25 is really more like a caravan with sails. To be blunt you are better off buying another 25 footer like a Triton, Folk boat or Top Hat. Admittedly these boats wont have the 6' headroom or space of a Roberts 25. But they will still out sail your boat even with the worst skipper at the helm.
As for your ballast issue, you could coach screw some lead ingots to the side of the fin and then fair them in place. You made need to beef up the bilge for the extra weight and leverage?
Cheers

[wingssail]

Apparently these were often home built from plans. Possibly yours was not built to spec and has less ballast than designed but I would not assume that.

I would not recommend adding ballast yourself to the keel. It may not be structurally suitable to added weight down there. A better plan would be to add ballast under the cabin sole (well secured) and try it out.

But honestly, this is a light boat with minimal ballast and probably it is going to act the way you describe. You may not be able to satisfactorily turn it into a much different boat.

I'd recommend you learn to sail it to the best way you can and adapt to its characteristics. If you don't like it, get a different boat and do a test sail before you buy.

[chrisr]

before adding any weight to the keel, be very very careful of the strength of the hull / keel joint, floors, sub-frame etc. the weight you add is multiplied by the keel length and then amplified further by wave action

it's all too easy to rip the keel off if done badly. if in any doubt, get expert advice (in fact do this even if you don't have any doubt !)

that having been said, we added 250kg to the bottom of a race boat keel a few years ago and it was enormously successful. just make sure you get it RIGHT !

cheers,

[Hesti]

Is this the designer of your boat? https://www.bruceroberts.com/ If yes - why not try and get his view?

As stated already by others, the additional weight combined with the leverage from the bottom of the keel to the hull-keel joint / floors will put additional stress on the bolts, surfaces in the joint, floors, ... . Only the designer really knows the load assumptions and safety margins he used when designing. The alternative would be to recalculate all these items. Some further changes might be needed on top of just adding the ballast.

If there is any hint at the boat having been homebuilt, there is some likelyhood, that it was never built as designed. Again, the original designer would be the best to discuss with what might be wrong.

A friend once added ballast to his bilge keeler, both internal and at the bottom end of the keels. He was very happy with the result - but also had aligned his changes with the builder of the boat before implementing them. So, it may well be worth it. IIRC, the builder adapted the design (added ballast) based on the experience from this one modified boat.

[GordMay]

Greetings and welcome aboard the CF, Robertsfeet.

You’ve received some good commentary, and cautionary advice.

As noted, the ‘Adventurer 25' is a DIY Trailer-Sailer Boat, designed by Bruce Roberts.
You might ask him:
➥ https://www.bruceroberts.com/PIRATED-PLANS.htm


You might also be interested in several EXPENSIVE options, offered by MarsKeel Technology
➥ https://marskeel.com/

[thomm225]

Looks like the ballast is fine for that size boat as the Bal/Disp ratio is about
42.5 %

If this is the one you have....

https://sailboatdata.com/sailboat/roberts-25

[Robertsfeet25]

This is some really good advice, much appreciated guys. As mentioned, I was a little worried about adding too much additional weight and stressing the joints and having the keel ripped off. Testing the added weight first in the keel is a good idea, but I'm not sure it would simulate added weight to the keel. I have pushed her to the limits a couple of times in 30knot winds and 1.5 metre swell, part of me wonders if it even was made to spec as the fibreglass walls of the v-berth would flex atrociously when coming down on waves on a lean. Was seriously concerned I was going to sink on that voyage she's going to need some reinforcing I think.

I think I will resign myself to the fact that it is what it is and learn to live with her poor sailing ability, but on the flip side, she is very comfortable for such a small boat. And between us, I only paid $200 AUD for her in relatively excellent condition, so I shouldn't complain about her flaws. Thanks again everyone for your advice!!!

[Greatest Lakes]

$200 is definitely a deal. It has 4,660 lb / 2,114 kg displacement and 1,980 lb / 898 kg on the keel already, so depending on how much your lead ingots weighed, it might not make much difference. Compounding that is the shallow draft. If you were to through bolt 2 pairs of 75 lb ingots, in a manner that would sandwich the base of the keel, you'd get the best location, but arguably the same or less righting moment than having a husky friend sit on the rail.

Enjoy it for what it is. If you decide later you need more of a performer, you might find you are a better sailor from the experience.

[Pete7]

[QUOTE=Robertsfeet25;3498145 I have pushed her to the limits a couple of times in 30knot winds and 1.5 metre swell, part of me wonders if it even was made to spec as the fibreglass walls of the v-berth would flex atrociously when coming down on waves on a lean. Was seriously concerned I was going to sink on that voyage she's going to need some reinforcing I think.[/QUOTE]

I don't think you are going to get a light weight 25ft trailer sailer to do any better in those conditions.

I would leave well alone and enjoy her for what she is. You can of course make very use of her ability to be towed quickly to new cruising grounds.

Pete