Another outboard for the v floor Waveline. . . Will it cavitate?

Lee1 · 14 April 2018, 17:31

Hade some issues with short shafts cavitating on my high transom v floor Waveline. Just mounted my new Mercury 7.5 I was hoping to use as my back up this season and the cav plate is lining up spot on but I bet it will cavitate like the previous short shafts, the long rear tubes and big planning tabs keep the Waveline stern really high I will give a try though as I like and rebuilt the merc 75 (I think this merc is maybe standard shaft not a short and a few inches longer than what we know as a short nowadays (the merc is a 1973 I believe) I will measure the merc length when I pack it all up later, be great if it doesn't cavitate I will have my backup outboard sorted!

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Lee1 · 21 June 2018, 23:48

Well the time has come to decide what to do with this high transom V floor SIB, it doesn't ride well nor right with my trio of thunderbolts: 4.5, 7.5 and 20hp (all standard shaft around 17-18inches, I no longer have the Mercury 25hp long shaft and I'm not sourcing further long shafts for my own use just for this boat) so it's either cut out a good few inches from the middle of the transom or sell the boat, I can't decide. . . (The boat will work with short/standard shafts but not if you want constant speed planning) I like the boat due to the long rear tubes and the huge planning tabs it takes the merc 200 20hp weight (45kg) like it's a two stroke 5hp on their, the boat looks good and has many years left before any reglueing etc. . Is needed, it's a rare boat which I like, the high transom is better for less water over the stern, the huge stern buoyancy means I can stand at the stern with the 45kg outboard and it still doesn't even attempt to want to flip, I like all of the above but none of that's any good if it doesn't keep on the plane in the slightest chop! The negatives for me to be happy to let it go are: Its too small for me to be honest anyway at 2.7m, I really don't like the V floor (not just on this boat but generally I don't like them)
But. . . With the right transom height and the huge buoyancy this may just be a power SIBers dream i.e. It will plane with 3 people with ease in the chop with the merc 20 where as neither the honwave nor sunsport 2.7 V can take the merc 20hp 45kg weight like this SIB can!

So what's the verdict. . . Let's have a poll!

1: Chop the transom, try it out and then if it doesn't give the desired 3 person hyper planning at least it will take a short shaft for the next owner, the only downside with this is that it's no longer original although the chop will be professional.

2: Sell and get a brand new SD290 too use with my trio of mercs.

(if I sell it my replacement will ONLY be a new red excel SD290, so no other boat recommendations please in your poll decision please! And I'm now a merc thunderbolt enthusiast so no other engine suggestions also lol)

WhiteShark · 22 June 2018, 09:15

Have you considered selling 2 or 3 of the engines and getting one 20hp with a longer shaft ?

Pikey Dave · 22 June 2018, 09:23

Quote:

Originally Posted by Lee1

.......although the chop will be professional

Will you have to send it off to get that done, or will you find someone local to do it?

beamishken · 22 June 2018, 11:08

Id say cut the transom, 95% of sibs that size will be standard shaft they dont need to be long shaft and for most owners its far easier to fit a short shaft in the average car boot. I've always found long shafts tend to be just too long to fit across a car boot

WhiteShark · 22 June 2018, 11:17

It just seems odd that it would be manufactured with such an obvious defect. Does the boat actually stipulate that it is built for short shaft ?

willk · 22 June 2018, 11:32

Quote:

Originally Posted by WhiteShark

It just seems odd that it would be manufactured with such an obvious defect. Does the boat actually stipulate that it is built for short shaft ?

To me, the SIB in the photo looks like a perfectly normal 10' tender with a bog standard short shaft egg whisk on it.

Lee uses the term "Standard" for both Short and Long shaft so unless he actually measures the bracket to antiventilation plate and the transom height, it will be difficult to call it from photos etc.

IMO he should definitely have a professional cut the transom down a few inches and report back later with a full analysis...

Lee1 · 22 June 2018, 19:45

No I use the term for stand shaft for the older engines like thunderbolts sea horses etc that are now referred to a short shaft there are around 17/18 inches the later actual short shafts are 15/17 inches long shafts are generally referred to around 22 inch and extra long 23 plus so where does that leave the 17/18? . . . . Standard shafts!

willk · 22 June 2018, 20:58

Quote:

Originally Posted by Lee1

No I use the term for stand shaft for the older engines like thunderbolts sea horses etc that are now referred to a short shaft there are around 17/18 inches the later actual short shafts are 15/17 inches long shafts are generally referred to around 22 inch and extra long 23 plus so where does that leave the 17/18? . . . . Standard shafts!

You are deeply confused. I'd suggest you swat up on the subject a bit. All IMHO naturally.

Tell me a thingy - those "long shaft" motors on your thundercat thread... were they REALLY long shaft or had a professional with 25 years experience in small boats simply misidentified short shaft engines? It's a really basic spot and you totally missed it. You've carefully avoided admitting it since, but IMO it's the mark of man if he can admit his mistakes - God knows I make plenty myself.

Lee1 · 22 June 2018, 22:11

No that wasn't any of my thunderbolts that was a Mercury long 25hp but as were no talking about another subject that was in another thread then yes the thundercats don't have the cav plate in line the transom bottom do they

Lee1 · 22 June 2018, 22:53

Decion made. . . It's going! I much preferred the excel sd290 of all the inflatables I've had and I can't get on with the v floor boats including this one so I'm going to get a new model one in red

beamishken · 23 June 2018, 09:13

Quote:

Originally Posted by Lee1

No I use the term for stand shaft for the older engines like thunderbolts sea horses etc that are now referred to a short shaft there are around 17/18 inches the later actual short shafts are 15/17 inches long shafts are generally referred to around 22 inch and extra long 23 plus so where does that leave the 17/18? . . . . Standard shafts!

Seems to be a difference of opinion on shaft lengths
The accepted standards are:-
Short or standard 15"
Long 20"
Extra long 25"
Extra extra long 30"
Only exceptions being odd engines from certain ranges can vary a little from these specs and the rnli commissioned some mid length 18" mariner engines

Lee1 · 23 June 2018, 22:08

So wher does that leave 17-18 then?

Anyway back to the chop or not chop, this is interesting, first Plastimo V floor I've seen! and notice how the transom is stepped down. . . . Interesting

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Poly · 24 June 2018, 15:39

Quote:

Originally Posted by Lee1

So wher does that leave 17-18 then?

it leaves them as the special edition for the RNLI, a dodgy ruler or someone measuring the wrong distance!

Quote:

Anyway back to the chop or not chop, this is interesting, first Plastimo V floor I've seen! and notice how the transom is stepped down. . . . Interesting

There are many boats around with such styles, it’s almost like they want the centre of the transom to fit an industry standard height and the outside edges to be the best design for the tubes.

Lee1 · 24 June 2018, 22:34

I prefer a high transom with the middle cut to short shaft size, this gives less wash over the transom.

Lee1 · 26 June 2018, 20:31

Well it sold today via gumtree the guy knew what he was buying regarding the bigger than other v floor tabs, he also wasn't leaving without the 7.5hp (after I repainted it only yesterday!) i guess I don't really need 3 outboards for my personal SIBing, a big hp for main and a lightweight back up. It's a shame I couldn't get on with the 2.7m size of the boat and that I did not like the V floor like many do, oh well happy days his happy I'm happy, I guess it's time to order up the brand new excel SD in red, I do really like them Ive had a few used old ones and prefer them to all other similar sib makes in that size bracket, last one I had was a sd290 and that was roomy enough but I'm thinking tonight shall I get the SD330 not the SD290? Both come with 2 seats.

Had a look on eBay and gumtree for something else high end used that might need a bit of reglueing that would steer me away from the SD Volante but theirs nothing on right now and I'm sibless so new volante it is

No videos out there for the SD290. . .

The new model SD330:

https://m.youtube.com/watch?v=V8tgo5S66oA