15 HP on Zodiac 325 fastroller?

[IseeU]

325 has declared max 10 HP and max weight of outboard 52kg.
If I was to put on Yamaha 15 2S, which weights 36kg... do you guys think that would be a huge problem?
I mean it can't be *that* much difference between 10 and 15hp in terms of speed etc..? Specially since I drive quite slow in waves, so there is no difference how much extra HP is behind. And in calm sea, I don't see problem for this boat to go a little over 20 knots?

[rik_elliott]

it would be exciting at full throttle. if you power up too suddenly you could flip it, or get bounced out. as long as you are sensible and stick to 2/3rds throttle you'll probably be ok. i doubt anyone on here will say do it, so its up to you.

your insurance will be invalidated either way though.

[IseeU]

I understand what you mean, but...I really doubt 15hp has that much more acceleration than 10, that you could flip a boat...It is actually exactly the same engine as YAM 9.9 2S, which would/should be "perfect" for this boat according to Zodiac. Perhaps they only went on "extra safe" here to claim 10hp is max. Specially because I see mostly YAM 9.9 4 strokes installed on it, which weights around 10 kilos MORE than my 15...
Even Honwave's air deck 320, which is 5cm shorter, 15(!) cm narrower and has even quite smaller tubes, while weighting exactly the same, have claimed max hp of 15hp.
Confusing it is

[jeffstevens763@g]

well if it were me and i had a 15 but the boat max was 10 i would use it and probably stick 9.9 stickers on it and just be sensible not telling you to do it but the boat will be tested to well over the 9.9 hp in any case

[Fenlander]

The Zodiac fastroller transoms are very thin... far more so than Chinese SIBs and the more expensive Zodiacs. I have experience of causing one to delaminate at the ends where it joined the tubes when using in heavy seas and with all the power of a 15hp.... the Zodiac was almost new.

Not saying don't but use caution if you do.

[IseeU]

Really? That doesn't sound good :/
I though the boat was the same as Cadet S, only bottom being inflatable.
But those were probably older FR models 310 and 340...Were your model one of those, or one of the newer ones (325, 360) ?
Will have to keep on looking and waiting for another one I guess, if that is true. Thanks for the info.

[office888]

Originally Posted by Fenlander

The Zodiac fastroller transoms are very thin... far more so than Chinese SIBs and the more expensive Zodiacs. I have experience of causing one to delaminate at the ends where it joined the tubes when using in heavy seas and with all the power of a 15hp.... the Zodiac was almost new.

Not saying don't but use caution if you do.

Zodiac only used two different transoms for welded transom boats. A narrow one, and a one wide one. The thicknesses are the same, which are constructed from aviation grade marine plywood (birch) which is sprayed with catalyzed two part polyurethane paint for rot resistance.

I have seen transoms develop a slight "bend" due to damp wood and heavy use, but the only time I've ever seen a transom break was due to severe rot (bottom ~10cm were complete mush).

Chinese transoms tend to be constructed from very bad quality plywood, but their "industry standard" is to encapsulate the transom with 6mm pieces of ABS plastic fascias instead of paint, so you'd never know...

[Fenlander]

Office888 your Zodiac experience is far greater than mine and I respect that but I still had the issues I had. The Fastroller is obviously built down for its light weight and mine suffered badly.

The Fastroller transom is far thinner than the older Zodiacs (pre 1990) I've owned, the Aerotec, the current Classic models and pretty well every Chinese SIB (where to my knowledge the construction method is not giving problems). For that reason I guess Zodiac have massively downrated the OB size advised over their thicker transom models. My 1970s Zodiac around 3.1m was rated to 20hp yet the Fastroller 325 is only rated to 10hp as the OP says.

Mine was a brand new Fastroller 360 fitted with a 2-stroke 15hp which was the correct max size OB.

After it's first week's use at sea (Scottish West Coast) both ends of the transom had started to delaminate and the high pressure keel to floor attachments were tearing.

The Zodiac dealer collected it for full refund.

Now we did give it hard use with 2 adults, 2 teens and a dog plus kit pushing it hard through some rough tidal races but it should have handled that as have every one of the other 9 SIBs we've owned.... inc ones up to 40yrs old and Chinese made models.

Not anti Zodiac just reporting facts and why I personally would not 50% overpower a Fastroller.

Images attached... remember this was a brand new boat after just 5 days use.

[office888]

Originally Posted by Fenlander

Office888 your Zodiac experience is far greater than mine and I respect that but I still had the issues I had. The Fastroller is obviously built down for its light weight and mine suffered badly.

The Fastroller transom is far thinner than the older Zodiacs (pre 1990) I've owned, the Aerotec, the current Classic models and pretty well every Chinese SIB (where to my knowledge the construction method is not giving problems). For that reason I guess Zodiac have massively downrated the OB size advised over their thicker transom models. My 1970s Zodiac around 3.1m was rated to 20hp yet the Fastroller 325 is only rated to 10hp as the OP says.

Mine was a brand new Fastroller 360 fitted with a 2-stroke 15hp which was the correct max size OB.

After it's first week's use at sea (Scottish West Coast) both ends of the transom had started to delaminate and the high pressure keel to floor attachments were tearing.

The Zodiac dealer collected it for full refund.

Now we did give it hard use with 2 adults, 2 teens and a dog plus kit pushing it hard through some rough tidal races but it should have handled that as have every one of the other 9 SIBs we've owned.... inc ones up to 40yrs old and Chinese made models.

Not anti Zodiac just reporting facts and why I personally would not 50% overpower a Fastroller.

Images attached...

Pre-1995 Zodiacs had glued transoms, so the layup schedule was different.

Many pre-1990 Zodiac products had varnished MAHOGANY transoms, which is a dense and strong hardwood, which were able to carry the high HP ratings.

The Classic and Futura lines have heavier transoms, because they're designed as primary boats with higher HP ratings. The Cadet and Fastroller lines are designed as tenders with lower HP ratings.

Judging from your picture, it appears to be superficial cracking of the paint. Likely, the paint was overcatalyzed which led to embrittlement. As long as there is no delamination of the plies, from an industrial standpoint, it would only be considered cosmetic. Sand and repaint, problem solved. If you look closely, you can see that the cracks don't align with the plies of the plywood.

Can't comment on the tearing, I've never seen that before on an FR ACTI-V.

[Fenlander]

>>>appears to be superficial cracking of the paint

Maybe... maybe not... paint doesn't always crack in line with the underlying issue. Zodiac dealer agreed it was delamination sufficient to give a full cash refund.

Anyway broadly my point stands... Fastrollers are light so they are portable. Their HP ratings are low for that reason. Add in my experience and I would still not overpower one by 50%.

[jeffstevens763@g]

Interesting pictures David the paint coat I would say would not expand at the same rate as the ply not saying the ply hasn't split but that could be a reason too the other two pics are in my mind design faults with two semicircular cut outs giving a start point bit like a notch on a tear open bag in the second pic and the third well that's a joke never going to be man enough to last certantly see your point not to over power.

[IseeU]

Originally Posted by Fenlander

>>>appears to be superficial cracking of the paint

Maybe... maybe not... paint doesn't always crack in line with the underlying issue. Zodiac dealer agreed it was delamination sufficient to give a full cash refund.

Anyway broadly my point stands... Fastrollers are light so they are portable. Their HP ratings are low for that reason. Add in my experience and I would still not overpower one by 50%.

Yes, but how come than Honda has shorter, narrower and weighting exactly the same airdeck boat, which can officially take 15HP...Oh well I will keep on waiting for some nice FR340 I guess

[Fenlander]

>>>how come than Honda has shorter, narrower and weighting exactly the same airdeck boat, which can officially take 15HP

You are referring to the Honwave 3.2m air floor model? I guess because Honda know their transom is thicker and even if Office888 has his doubts about the sandwich construction Honda are obviously confident of its strength. Also the Honwave has a V-shaped air floor that's glued to the transom across the whole width whereas the Fastroller's air floor just touches the transom with only a couple of small plastic brackets to keep it in place while inflating.

>>> I will keep on waiting for some nice FR340

Because you see it is rated to 15hp? The FR340 & FR325 are effectively the same basic boat with shorter cones causing the length difference... the internal dimensions and transom thickness are the same or almost the same. The FR340 was allowed a 15hp maximum but in the brochure 10hp was advised so they were obviously aware 15hp was pushing it a bit then when the 325 came out decided to down grade to make the maximum the same as the previously advised hp.

[IseeU]

OK thank you for very informative answer
Than for my case perhaps Cadet 310s would be a better choice. While 340s is quite roomier, is also about 10kg heavier, and I would like to be as easy as it can be for carrying around (around 40kg would be perfect).
And since I am buying used one, I can't do much but wait for a good one.

[Fenlander]

>>>And since I am buying used one, I can't do much but wait for a good one.

Yes. We are looking for a used car for my wife at the moment... still after three weeks of looking we can't find the right combination of make, colour and condition. It can be a frustrating search.

I should say I have nothing against the Fastrollers having owned four... you just need to consider their specification and match it to your needs.