Allison Grandsport Ski Pylon

[Jr in Jax]

My Grand Sport Elite's Factory ski pylon has been one of the most disappointing features of my boat. It was always almost impossible to pull out of the carrier so I long ago drilled a hole through the rope groove so I could stick a large screwdriver in and twist/pull to get it to come out. It eventually got impossible so I sent it to a friend's machine shop to be straightened/rounded and had a Type 2 Titanium insert pushed into the hollow center to strengthen it. It eventually still froze up, probably due to pulling the Parasail.

I tried to use a come-a-long to pull upward to pull it out last year before the rally and ended up lifting the boat and trailer off the ground with out it coming out. Eventually the rope groove aluminum plug tore out of the stainless tube.
I called Allison about a replacement and found out it was $780 plus having to add a centerline stringer to my hull for it to sit on. There must have been a hull stringer added to the newer GrandSports.

I went in to pull the whole carrier out to send it to a machine shop to push the pole out of the carrier and found that the bottom mounted #14 sheet metal screws were mostly missing and the rest were very loose in the thin laminate on both sides of the bottom tunnel it sits in. When I unbolted the top I found what looks like wood was rotted away.

I am going to modify the carrier and ordered a new 2" solid aluminum pylon from Dana Marine [Thanks James for the idea from long ago]. I am sure that the loose carrier was twisting under the load and allowing the hollow pylon to bend, which made it seize when it was retracted.

GrandSport owners with the Factory Pylon need to check the attachment screws at the bottom. There is no way to check for rot at the top without pulling out the entire assembly which is a real pain.

 

[RoseXB03]

I have been debating on pulling mine out and covering the hole...

 

[Jr in Jax]

I have been debating on pulling mine out and covering the hole...

Dana Marine sells a nice O-ringed plug that will seal the hole once the pylon is pulled out [if it will come out]. I ordered one from them with the new pylon to plug the hole when the pylon is out.

I finally got my whole assembly out and bought a new 20-ton hydraulic press to try and push the pylon out of the carrier. The bracket broke before the pylon moved so I used muratic acid to dissolve the inside bore between the aluminum carrier and the stainless steel pylon. I then tried the press again and got the pylon to move about 4 inches before the end of the aluminum tube shattered [under 80,000# of force].

I am going to scrap the whole assembly and am building a totally plastic carrier that will not corrode and seize up the new Dana aluminum pylon. I am also flooring the area in front of my inboard tank with Starboard for me to set my [2] 6-gallon portables on since they are wearing the laminate back there.

 

[Lotus 50]

Do you keep your 6 gallon tanks under the hatch? I have thought of doing so but worry about fumes, venting, and spark

 

[Jr in Jax]

Do you keep your 6 gallon tanks under the hatch? I have thought of doing so but worry about fumes, venting, and spark

The internal compartment is well vented due to the hump in the rear hatch and there is also a ram air effect from the side compartments into the rear. When I run above 90 MPH it blows the rear plastic cupholders out of their holes into the floor of the cockpit. The 6 gallons are a necessity due to our three Honda PWCs that are with us many times on long trips. The Hondas get 7 MPG but only have 16 gallon tanks. My Grandsport/225 Promax with ACU/Steamwheel gets only 5 MPG but has the 30 gallon tank. We made a very fast run [60-85 MPH GPS] from Crystal Cove to Silver Glenn Spring [100 miles roundtrip + 20 minutes of no-wake] 2 weeks ago on just 20 gallons of fuel.

 

[Lotus 50]

I don't know my mpg or how far I go, but I can easily go farther than my 24 gallon tank will take me. OF course it's a lot less fuel efficient when I have to trim down for rough water or putz in no wake zones. No ram air affect with the SS hatch.

 

[Jr in Jax]

I used PVC plank boards [Home Depot] to support the Starboard in the rear compartment and to support the new plastic ski pylon housing I fabricated. I am still waiting for Dana Marine to ship my 46" 2"Dia solid aluminum ski pylon to drop into it. It must be backed up at the Annodizer they use. I also had to replace my bilge pump while I was under there due to breaking the outlet fitting while removing the hardened hose from it [it is about 5 years old].

I have purchased/tried dozens of different props, but have found that my best performance/gas mileage comes from my Trophy plus props [24,26,and a new 28]. The Trophy also gives me my fastest holeshot I just bought the 28" because Jake has warned me about our long runs on the ACU Limiter at 87 MPH with the 26" since I am still using Merc's oil injection and he feels the bottom brass bushing won't take that many RPM for long periods. My top end [95 GPS] comes with either a 30" Chopper II or my 30" Triton props.

 

[whipper]

I could never get my pylon out either so i grease it and it works good now. Its to short for my cowl so i use my 46 inch Dana pylon for water sports and only use the factory one as a hole filler and support for my rod holder. Trphys have also been my quickest props. My beat 25 is super quick. the best all round fuel economy and performance has been a 28 drag3 for 4 years now. Its on par with the 25 out of the hole has better top end and great fuel economy. The 25 is a little quicker in the mid range thats about it though. Stock 28 drag3 is worth a try JR there awesome!! a buddy uses one now also with his 225 GS and had tip cup put on his. He likes it both ways. Hes at 96 mph also with a 28 without trying to hard. They cruise nice at 80 for long distances.

 

[Jr in Jax]

James,
I think Mark is using a Yamaha copy on his Promax 225 Grandsport and it runs pretty good. I just like a little faster holeshot due to the huge loads I carry [42 Gallons of fuel, rafts, coolers, underwater scooters,,,ect...].

 

[whipper]

JR you need a rack for your GS to strap a couple of kayaks on there also and search lights.. Yours sounds like mine turned into a SUVGS also these days. haha

 

[procomp]

whipper, get yourself a 26 drag 3, even better. Worth the extra fuel............

 

[whipper]

Yes I like 25-28 pitch props the best 3 or 4 blades. i think your right about the 26 drag3. i know I really really love my 28 drag3 stock form. I can imagine i would love a 26 also for the extra acceleration and load carrying ability.

 

[smiley88]

Dana Marine sells a nice O-ringed plug that will seal the hole once the pylon is pulled out [if it will come out]. I ordered one from them with the new pylon to plug the hole when the pylon is out.

I finally got my whole assembly out and bought a new 20-ton hydraulic press to try and push the pylon out of the carrier. The bracket broke before the pylon moved so I used muratic acid to dissolve the inside bore between the aluminum carrier and the stainless steel pylon. I then tried the press again and got the pylon to move about 4 inches before the end of the aluminum tube shattered [under 80,000# of force].

I am going to scrap the whole assembly and am building a totally plastic carrier that will not corrode and seize up the new Dana aluminum pylon. I am also flooring the area in front of my inboard tank with Starboard for me to set my [2] 6-gallon portables on since they are wearing the laminate back there.

I know ski pylon is always brought up but I am trying to find the base that goes attached to the bottom of the boat to put the ski pylon in. I have a Grand Sport. looking for a little info on where to order one or if anybody around has an extra one thank you for your time and please point me in the right direction

 

[Jr in Jax]

When I called Allison about a new base and pylon, they told me that the new Grandsports have a center stringer that the new pylons saddle onto. Mine has a T shaped bracket that spanned the open center and attached with screws into the side of the tunnel. I did not want to modify my hull with the new stringer plus $800 so I built my own that can not corrode.

By the way, I ordered a new aluminum pylon from Dana Marine well over a month ago. Each week when it does not arrive, I call and they give me a different excuse and a promise it is ready to ship. I am starting to wonder if they are a viable business.....

Update: Since I posted this, I received a UPS shipping notice from Dana Marine; let you know when it arrives.....

 

[ROBERT CROSS]

Ski-pylon? .....so thats what that is. I use WD40 'dry lube' and can raise my seat quite easily.
The lower mount does saddle the center stringer on our '04.

Bob

 

[whipper]

Robert ever since i saw this pic of your seat on yours ive done this also! That is such a great Idea the seat fits perfect in there! When im anchored and casting of the back deck i some times sit and cast of the pylon.

 

[FloridaGS]

Bob,
What seat do I ask Bill for, how much was it....
And it looks like it went right on the existing pylon or did you modify another one.
Thanks for the info, I need that setup...

 

[ROBERT CROSS]

I just lift the passenger seat out and set it on the pylon, the seat post fits like it was made for it, no mods needed at all.

 

[FloridaGS]

Wow...if that was planned...I am IMPRESSED! You got to love these boats. Thanks for the quick reply.

 

[whipper]

it took me a week to remember the center seat flips out. haha the nice thing about the passenger seat is you can turn it right around for the spotter when skiing or tubing. Thats actually were I sit when floating with it turned around you can rest your feet on the back bench.