Revenger build thread!! - Page 13

Jon Fuller · 05-04-2010, 12:22 PM

As a comparison (with the slow, semi displacement Aquastar cruiser/barge) my Phantom 28 has along the centreline, an outer laminate with an overlap comprising of 8 x 600g woven rovings + associated 450g csm's in-between, then 1/2" balsa core, then another 4 wovens + csm forming the sandwich, then a 4" high x 2" wide douglas fir hog, laid on a couple of bedding csm's, and a woven over that.

motorvator · 05-04-2010, 12:31 PM

As a further comparison my SM has a similar lump of timber through the centreline. Whilst my structural engineering knowledge is housing based, I'm gonna guess it's there for good reason.

larby · 05-04-2010, 05:59 PM

Quite a difference there then! I do appreciate that the aquastar is a totally different kettle of fish, it's just the only one I knew the thickness of.

I spoke to several people locally and on here, one of whom works for a very respected powerboat builder, who told me this centre longit isn't required.
I also had a check of a big block v8 revenger 'blue dart' owned by a friend here, this didn't have one either.
The glassing now in mine is substantially thicker than it was when I bought it, not to mention that now it doesn't have layers of woven straight together to cause mass delamination.

It survived for 20 years of racing like it was, with piece-of-crap stringers that weren't even bedded in or glassed over and half the thickness of glass, so I'm happy to believe it'll continue to last as it is now.

I appreciate I may not be doing it 'perfectly', but as most have said to me, there is no right or wrong way, just different ways, but most people are passionate that their way is the only good way.
I do really appreciate all the advice people have given me, it really is vital, but I can't take all of it all the time, as most of it contrasts what another expert has told me along the line somewhere. I've just got to try to figure out what suits me best.
It's nowhere near the size of Jon's P28, with half the weight in the back, so about half the glass sounds ok to me. I assume you P28 is built heavier to 'extreme leisure' spec, made very much to last, whereas I'm building mine to race.

Should it turn out to be a steaming pile, I'll throw it away, learn a lesson and start saving. I don't personally think I need to worry though.

James

Big Dutch · 05-04-2010, 06:24 PM

Hi James
How much weight do you think you have added to the race Boat then ?
Looks like you have laid it up for the rough

Could do with some extra GGs now !

I would like to see a bit of something in the keel to cope with any deflection though its like a ridge in a roof really

Jon Fuller · 05-04-2010, 06:45 PM

I wasn't criticising your spec, more a case of pointing out that a slow tub, albeit a large expensive slow tub, undergoes somewhat different stresses and strains to a fast boat and doesn't make a very good comparison.

My P28 has exactly the same hull laminate schedule as Rogers 'Wentworth Auto & Marine' / 'Victory Inn Hamble' race boat. It's only my deck that got 'a bit more', (balsa core all over, rather than just in the king plank) as I wanted to be able to walk all over it without the classic Phantom 'soft under foot' feel in the outer foredeck. The addition of 1/4" balsa in that area sorted that requirement.

larby · 05-04-2010, 06:47 PM

Not sure to be honest. Half of me would say a race boat should be thicker to put up with the abuse, half says it should be lighter to be as fast as possible.
I guess the answer is it should be better built from better materials and to a better standard to combine the two, lighter but stronger.
I don't even know if some leisure boats even use woven?

People I spoke to about this before I started all seemed to think what's in there will be sufficient, and as I said, it's twice as thick now than it was. Not forgetting it's also got the bulkheads to keep everything in place, the fuel tank held down against it (seperated by 20mm foam) from the fwd bulkhead to the rear bulkhead, with the floors also bracing the stringers together. The rear will be all braced up by the engine cradle bolted to the stringers, transom and rear bulkhead, plus two bars and the engine bolted between the two stringers.
Given that this creates a traingle with the shape of the (rather deep) v, the strongest shape known to man, I can't see where it's gonna go!
Going back to the Phantom comparison, my v is considerably deeper, so therefore less likely to deflect compared to the flatter bottom of the Phantom.

It's getting extra GG's, so should go well enough to wipe the floor with any batboats, we'll leave that subject till she's out there and able to prove her own though eh

James

Jon Fuller · 05-04-2010, 06:53 PM

Mine has a 24 degree deadrise in the outer running surface, with a 20 degree section through the centreline.

larby · 05-04-2010, 06:54 PM

Quote:

Originally Posted by Jon Fuller

I wasn't criticising your spec, more a case of pointing out that a slow tub, albeit a large expensive slow tub, undergoes somewhat different stresses and strains to a fast boat and doesn't make a very good comparison.

My P28 has exactly the same hull laminate schedule as Rogers 'Wentworth Auto & Marine' / 'Victory Inn Hamble' race boat. It's only my deck that got 'a bit more', (balsa core all over) as I wanted to be able to walk all over it without the classic Phantom 'soft under foot' feel in the outer foredeck. The addition of 1/4" balsa in that area sorted that problem.

That's cool Jon, likewise I wasn't meaning to come across argumentative, just stating my side. As you know, I greatly respect your opinion on this build, you've been a great help, but obviously sometimes I don't need to go that far!

Out of interest, bearing in mind what I've said above about how it used to be, and that what I've added is on top of what was already left, would you say I've applied sufficient glass? It is quite a light layup in general at the end of the day.

I've only ever had the pleasue of seeing your Phantom once, briefly, and on dry land, but it really was stunning. No doubt one day I'll see it properly on the water, and if I'm really lucky manage a quick ride!

I know what you mean about the soft Phantom decks!

James

larby · 05-04-2010, 06:57 PM

Not sure what mine is exactly, I just roughly measured a friend's P25 in comparison to mine, and I had about half the 'v' again of his. I'll have to measure the deadrise of both properly some time. IIRC, my 'v' was about 10" deeper.
That said though, the P28 could be completely different for all I know!

Jon Fuller · 05-04-2010, 07:07 PM

Quote:

Originally Posted by larby

IIRC, my 'v' was about 10" deeper.

Bear in mind, a P25 has a 5' chine beam, yours is probably closer to 6', so measuring the height will give a false comparison. You need to measure the actual degrees.

Vertical dimension from chine to keel, would, if the boat were 8' wide, be much larger.

Having said all that, the Phantoms are relatively shallow.

Big Dutch · 05-04-2010, 07:16 PM

My Boat(race one) is built up on a hog of 48mm x 67mm
It has stringers and frames and has just had a very simple repair done to the wing-it took me 23hrs to do it but its puurfekt now

Sorry no build thread as I had to get things done !

larby · 05-04-2010, 07:55 PM

Well yeah, but then it is wooden, so a touch different!

Jon, chine beam was within a couple of inches, though overall beam on mine is more due to the sloping sides. The reverse chine of mine makes the actual v about the same. I'll measure the angle next time I'm up there out of interest

jw. · 06-04-2010, 12:03 AM

James I'm not a racer and I'm not criticizing your hull structure but it strikes me as rather light. I'll pass this by you; if your landings were all nice and square and you were boating where there are no waves to beat you from the side then your notion of the V being strong and adequate might be right but you wont be. You're bound to be landing with the hull on its side and also landing across waves where the water support is not even. You are then needing the flat hull side to resist bending in on the landing side and out on the less loaded side. Given also that you are putting in rigid bulkheads across the hull, if there is flexing you're asking for cracking at the bulkheads. I bet there will be substantial flexing when at the extremes of load the hull will need to endure. If it was me, I'd be doing something to make the running surface more rigid. I realize there would be a weight penalty but better that than a cracking penalty after all your hard work. Also, I'd be prepared to bet a rigid boat will be faster and better handling than a flexi one, accepting that all boats are going to flex to some degree. IMHO of course.

Jon Fuller · 06-04-2010, 08:12 AM

Quote:

Originally Posted by larby

Jon, chine beam was within a couple of inches, though overall beam on mine is more due to the sloping sides. The reverse chine of mine makes the actual v about the same. I'll measure the angle next time I'm up there out of interest

Well, the revengers aren't wide, but you can get a pair of small blocks side by side in the SC version, which you'd never do in P25, so there must be a fair difference.

Anyway, good luck and don't lose momentum. it'll be wet before you know it.

Jon Holmes · 06-04-2010, 11:38 AM

keep up the good work Larby and its nice to see advice being offered to assist you in this build.

Jon. In sunny Northern Cyprus.

PayCheck · 09-04-2010, 01:56 AM

Nice work Larby - it's great to see the improvements you are building into the hull.

BTW-Checkmates don't carry the extra keel timber either.

glen76 · 11-04-2010, 07:35 PM

Quote:

Originally Posted by Jon Fuller

As a comparison (with the slow, semi displacement Aquastar cruiser/barge) my Phantom 28 has along the centreline, an outer laminate with an overlap comprising of 8 x 600g woven rovings + associated 450g csm's in-between, then 1/2" balsa core, then another 4 wovens + csm forming the sandwich, then a 4" high x 2" wide douglas fir hog, laid on a couple of bedding csm's, and a woven over that.

JF is your balsa core across the entire running surface? Have you got any thru hull fittings?? If so dod you not fit core there? Same with deck, is there any balsa core where your cleats etc are??

Thanks

Jon Fuller · 11-04-2010, 08:02 PM

Depends where it is (the skin fitting) and what type.

The stainless thru hull water pickups have an internal flange that bolts through the running surface, so in the area they are the balsa has fillets (tapered edge) with a relief leaving an area about 4"x4" where the inner & outer laminate come together. Obviously a bolted flange would crush the balsa otherwise. On mine, there's a 3rd area done the same way for the depth sounder transducer to fire thru, as the solf balsa would have insulated the pulses.

For the plastic skin fittings such as bilge pump outlet etc, in the topsides, they're fine, as long as the raw balsa edge is well sealed after drilling the hole (dig out a bit of balsa around hole and fill space with sikkaflex) and before installing the fitting

Big V · 11-04-2010, 08:42 PM

Quote:

Originally Posted by larby

should go well enough to wipe the floor with any batboats

James

What's the weather like today in that dream world that you are living in!

larby · 09-05-2010, 08:54 PM

Well I had to tak a bit of a break from the build to get the first local race sorted, back on track now though!

I'd worked out the supercharger was gonna stick out of the the engine bay by a good foot, so i wanted to make a hatch that was level with the top of the boat to reduce the amount of scoop required.
It took me a weekend to make and was a complete waste of time! Turns out the angles on the back are all different from one side to the other, and I'm not about to try making a wonky hatch to fit.
Here's some pics of hatch 1, it looks ok in the pics but there were small variations in gaps etc that really bugged me, so i started again.